Oh! You pretty things

Winter has arrived also for the Andean crops in my garden, so it's high time for some updates. 2015 was my first year growing oca (oxalis tuberosa), a major root crop in many Andean countries and probably one of the better-known unusual tubers from that region. In total I planted 14 known varieties and 7 varieties that I tested for the Guild of Oca Breeders (GOB). Due to a bit of self-induced force majeure however, the former got thoroughly mixed up, so from now on they're all going through life completely anonymous (at least in my garden). I'm not one to judge a tuber by its name, and at a very practical level it really doesn't matter.

The oca patch in the middle of October

Ideally, the oca growing manual clarifies, one keeps her/his plants alive until the beginning of December if one is to benefit from a fully matured crop. This is because oca plants get slightly confused in the long-daylight hours outside of their native Andean range and respond by refusing to produce tubers until after the autumn equinox. Here on the west coast of Skåne, which you could think of as the California of Sweden, we usually have the first frost sometime in November, or even, as in 2014, the beginning of December, which is pretty good in oca-growing terms. Not so this year though, when a forecasted 4°C one night at the end of October turned into an ominous -0.6°C and caught me completely off guard, therefore pretty much decimating the oca patch. Highly unfortunate considering the 3 weeks of mild and frost-free autumn weather that followed... The GOB plants got completely killed, while the other plants got frosted about 3/4 of the way, probably because they were spaced closer together and had much more foliage. Again according to prevailing oca-growing dictates, one is supposed to leave the tubers in the ground for some two weeks after the plants are killed by frost, since the tubers continue to bulk up quite a bit during this time. Which I duly did, albeit impatiently so.

White variety, 540g

I can testify that, because of its colorful nature, oca is a highly satisfying crop to harvest. I would say it's a bit like gathering easter eggs. Except of course that oca is so much more exciting than easter eggs! I mean, aren't they incredibly pretty? So euhm... yes, I dug everything up, bagged all the tubers per plant, washed them, weighed them, and then selected the ones I want to continue with next year. Considering the earlier-than-ideal harvest, I was pretty happy with the results (but then again, I have never grown these before so I have nothing to compare to and probably would have been happy with nearly anything). Most plants produced somewhere around 200-300g of small to medium-sized tubers, with the best one being a completely white variety that yielded 540g. According to the information over at Cultivariable, oca can yield up to 1kg per plant. Clearly, I'm pretty far away from that, but it's a pretty decent start nonetheless. I'm saving all but the poorest performing varieties for next year, since I want to ensure that I continue to have the diversity required to produce seed. Oca is namely a bit picky when it comes to pollinating partners.

Oh! You pretty things! These are the discards,
the tubers from plants that yielded less than 200g

GOB14178 - This from two plants

Seed!

Speaking of seed, quite a few of my oca flowered, and some produced seed in late summer and early autumn. With some 25 seeds in total, this can hardly be called a gigantic harvest, but it's enough to do a little bit of excited experimenting next year. For the more substantial work of breeding that elusive daylength-neutral oca variety, I'll be relying on the likes of the GOB. Sadly though, this year's GOB varieties didn't do well at all in my garden. The only one that produced something worth mentioning was GOB14178. While the yield of seed-grown oca is bound to be very variable, the main reasons for the substantial difference between the GOB and non-GOB varieties in my garden are probably environmental. I planted the GOB varieties in a new plot of land, that I acquired just this year, and which turned out to have very low soil fertility and a pretty severe wireworm infestation. Basically, the GOB plants never looked happy and remained stunted throughout the season. In other words, I'm blaming mismanagement by the previous owner. Objective #1 for next year: Nurture the soil, and provide better conditions for GOB trials.

Other oca objectives for 2016: Regrow all but the worst of this year's varieties, keep them alive longer than this year, and produce more seed. Oh, and grow out this year's seeds. Ultimately, as I source more varieties, I also want to start selecting for taste and texture. So far I've only tasted a few varieties, but all have been very good, and some were outstanding. The texture seems to range from quite watery to potato-ish, and the taste from quite sour to starchy, to fairly sweet. Very interesting tastes, actually. I think I would like to select for varieties with a higher dry matter, and for less oxalic acid (i.e. a more neutral or slightly sweet tasting).

Oca's here to stay!

Ipomoea batatas vs the Swedish weather: 1 - 0

Buds and more buds, but no seeds

Time for results! On 3 October I decided that summer was irrevocably over hence that it was time to find out what the sweet potatoes had been up to this paltry summer. Let's start with the bad news. Despite some pretty eager hand pollinating from my side and profuse flowering in at least 8 sweet potato varieties by the beginning of September, my plants failed to set a single seed. Not one seed. I'm not quite sure why this is, though I have some ideas. Sweet potatoes are self-incompatible, but with 8 quite genetically distinct parents that should not have been an issue. Lack of pollinators is a possible factor, and I did indeed see very little insect activity around the flowers at the time, even though bumblebees are generally quite abundant in my garden. Perhaps I have a species of bumblebee with a very finicky taste in pollen, or perhaps there were simply more exciting flowers around at the time. The most likely saboteurs in the grand sweet potato breeding scheme though, are environmental conditions. I need to look into this in more detail, but given the failure of hand pollinations it seems possible that succesful seed set was inhibited by low temperatures (something we've had plenty of this summer) and/or inadvantagous daylength. Just today I was reading Ottawa Gardener's post on how she managed to get a few seed from Georgia Jet and a purple variety in her Canadian garden, so I'm convinced that it should be possible to produce seed here in Sweden as well, provided I can create the right conditions for it. I'll be putting some more thought and effort in this for next year, perhaps growing a few particularly floriferous varieties on clear plastic to expose them to higher temperatures. Last year at least I had some plants flowering as early as July, which seems like it might be a more sensible time to produce seeds here.

Unfortuntately, vine growth is not a good indicator for
tuber formation

On to the good news then. As my pitchfork and me made their way through the first sweet potato row that sunny Saturday at the beginning of October, I became increasingly jubilant. I won't be winning any yield contests anytime soon, but my expectations, admittedly quite low, have certainly been exceeded. As could be expected, the majority of varieties failed to produce any roots at all. Sadly, this includes some particularly promising, and tasty, varieties like Orphan and Mukekuru tarya bibiri, both of which produced very vigourous vines but had roots that were no thicker than a pencil. Nothing worth saving there. The Euro/American varieties overall did quite ok, though Georgia Jet was, again, a disappointment. This is a mystery to me, though I only had two plants and both came from cuttings that I was forced to keep alive throughout the winter, so they might not have gotten the best of starts. I'll be looking for a new source of Georgia Jet next year, ideas and donations are warmly welcomed.

As last year, Nordic Purple produced very long but fairly thin roots that are hardly worth eating, but since it is the most prolificly flowering variety I have I will hold on to it. Burgundy produced some good-size tubers, as did Bonita, Nordic White and (somewhat less so) Nordic Orange, so I will be saving some of those for next year, particularly since all of them flowered as well. By far the best variety was T65. This is the variety I had expected most of and it didn't disappoint, generally producing two or three supermarket-standard tubers per plant. Sadly enough, it doesn't seem to produce flowers, not in my garden during the last two years, and not in Frank Van Keirsbilck's for quite a bit longer. T65 is a Taiwanese variety that came out of a breeding project there, so perhaps any fellow sweet potato devotee knows of an interesting, flower-producing sibling out there?



Though the success rate amongst the African varieties was considerably lower, there were some pleasant surprises as well. Burundi and Bunduguza both bulked up enough to make me slightly excited. Bunduguza gave a fair amount of smallish roots, while the three Burundi plants actually produced roots that nearly rivalled those of Euro/American varieties like Nordic White. Others that I thought were worth saving for the moment were Kitekyeru, Alira, Kwezi Kume, Mushemeza, Kipapari and Rwabafurugi. By any standards, these are still very small sweet potatoes, but I think there might be something here to work with. With their high dry matter content, the African varieties are very different from the ones you would normally find in Europe, so it seems worth hanging on to as many of them as possible.



Since the objective this year was to find the most suitable varieties for my climate rather than to maximize yield, I'm judging the harvest by the thickness of the roots rather than overall productivity. This criteria roughly gives the following classification, from thickest (about 3 fingers wide) to thinnest (somewhat wider than a thumb):

And the winner is...

1. T65
2. Nordic White
3. Burgundy
4. Bonita
5. Nordic Orange
6. Burundi
7. Bunduguza
8. Kipapari
9. Alira
10. Mushemeza
11. Nordic Purple
12. Kitekyeru
13. Rwabafurugi
14. Asian Yam 2
15. Kwezi Kume

15 varieties is considerably more than I have place to continue working with, so I will probably make a further selection later. A lot of the tubers are damaged by wireworm, which might provide problems with storage and cause additional casualties later in winter. For the moment, though, I'm very happy with this year's results. With an average mean temperature of 15.86 °C we had a fairly cold summer this year, particularly during June and July, which make me optimistic that this year's results can be replicated under most summers here. For anyone looking to grow sweet potatoes under similar climatic conditions, I'm convinced it's possible to get fairly respectable yields, consistently, provided one grows a variety like T65. I also grew the plants on ridges, which might have had a positive influence on soil temperatures as well. You could certainly increase your chances by using a plastic mulch, as advocated by Ken Allan, which is bound to boost yields considerably. Personally, I'm going to continue searching for varieties that do well also without plastic ground cover, though I might cheat a bit in order to induce early flowering and seed production. Yes, I'm just that stubborn.


You might be able to guess what I would like for christmas this year: Some more T65-class, early maturing and cold tolerant sweet potato tubers, and why not some seeds to top it off. Please?

Temperature data for Malmö, June through September 2015

2015 winter squash harvest

C. maxima - Green Hokkaido

Harvest time! All of the C. maxima plants have succumbed to end-of-season downy mildew by now, stems on the fruits have corked up nicely, and skins have hardened and faded in colour, so last week it was time to bring in the majority of this year's winter squash. Most people will leave their winter squash out in the field as long as possible, but maxima squashes actually don't mind being harvested just a tad early, about 40-45 days after flowering. Since I've had some problems with theft in my allotment, I choose to err on the side of caution and bring in the winter squash when I feel they've matured. They're currently spread all over my living room so they can cure a bit, after which they're going to the (unheated) attic for long-term storage. Having them heaped together like that is always a very satisfying sight. Name me one other food that looks as beautiful!

C. maxima - Sweet Mama

Anyway, before I launch off into another winter squash rant, here is what this year's crop looks like. The first number is the amount of squash per variety, the number in brackets is the number of plants there were of each:

15 [8] Sweet Mama
3 [1] Burgess Buttercup
4 [4] Sweet Meat Oregon Homestead
2+1? [5] Marina di Chioggia
1 [1] Galeux d'Eysines
1 [1] Blue Ballet
1 [1] Green Hokkaido

C. maxima - Sweet Meat Oregon Homestead

That's 27 squash from 21 plants, which is ok but it could definitely be better. Even though I increased spacing from last year, I think the plants were still too close together, which tends to affect yields negatively. Especially against the fence, where the Marina di Chioggia were planted, the vines were just layered on top of each other. Next year I'll be increasing my spacing further to 2mx1m, hopefully this will make for healthier plants longer into autumn as well. Sweet Mama is a semi-bush variety that needs relatively little space, so it is no surprise that it did so well compared to the others. The +1? for Marina marks a squash that is still growing and that I'm not sure will mature in time. Of the other two Marina's, one somehow got detached from the vine before it was fully grown, so I baked it the other day. While it completely lacked the typical sweetness of a ripe Marina, the taste was surprisingly good. It was starchy yet flavourful, a bit nutty and at times tasted exactly like mashed potatoes with spinach (which is a fond childhood memory of mine, in case that analogy seemed a bit random). I had one more piece right out the fridge a few hours later and that reminded me of cheesecake, which I suppose was mostly due to the texture. Surprisingly good for an immature squash!

C. moschata - Longue de Nice

As I eat my way through the rest over the coming months, I'll be saving seed from the very best for next year. I'm already looking forward to growing them out... The C. moschata are still in the garden, they need somewhat longer to mature and in contrast to C. maxima should actually stay on the vine as long as possible. There's two Longue de Nice fruits that I believe are nearly mature, and then there are a bunch of Waltham Butternut and Long Island Cheese that only started flowering very late, so it's yet to be seen if I'll get a fully mature squash off either of those. The Longue de Nice was aborting a lot of fruit in the beginning of the season. Fruits would first grow very long (some grew to 40 cms) but the head (where the seed forms, to the left in the picture) would fail to bulk up, and then it would start rotting from the top down. I believe this was due to poor pollination (there were no male moschata flowers at that time), which might mean that the moschata didn't cross with the pepo after all (or they crossed but then aborted anyway). I'll save seed from any mature (and tasty) moschata that I get and trial it next year. If it's contaminated with C. pepo genes I'll drop it, otherwise I'll try to develop a C. moschata landrace as well.

I leave you with the biggest and most alien squash coming out of the garden this year:

C. maxima - Galeux d'Eysines

Batata anxiety

Mushemeza (left) and Sula 1 (right)

With just a few weeks left of sufficiently high soil temperatures, sweet potato anxiety is setting in. Harvest or no harvest, that's basically the question at the moment, I'm under no illusions that I will have a respectable yield at this point. May, June and July have been unseasonally cool here, but the weather did pick up a bit in August, so there has been quite a lot of top-growth over the past weeks. Nothing like last year though, when vines were all over the place. The slips that were planted at the end of May still seem to have an advantage over the others, even though temperatures were suboptimal at that time, so I might try to push the growing season a bit more next year. A plastic mulch would definitely have helped a lot with this kind of weather, but I've got excuses for not going down that path... I'm trying to evaluate possible cold-tolerance, plus I feel no desire to provide another feast for the resident vole population. In other words, I'll just have to suck it up and hope that some plants will at least provide me with some seedstock for next year.

Bunduguza (top) and Kwezi Kume (bottom)

As a gardener, of course, there's always additional reasons for anxiety, and I found some in the recent potato harvest. To accommodate for ever-expanding garden experiments I've taken on a second allotment this year, which had been lying fallow for a while and was pretty much covered with grass when I first dug it last autumn. I've planted both the potatoes and the sweet potatoes (as well as all the mauka, some mashua and all of the GOB oca) on this plot, only to discover recently that it's infested with wireworms. Wireworms are the larval stage of a number of beetles, which burry into all kinds of roots and make them susceptible to rot. They prefer the roots of various grasses and are therefore quite common in newly-dug gardens, but they usually hang around for a few years after the grasses have departed and in the absence of their favourite food they will devour just about any root they find. All of this year's potatoes have had some degree of wireworm damage, some being more hole than tuber. Since potatoes are a definite dietary improvement over grass roots, I can't really blame them, but the idea that wireworms might at this very moment be burrowing their way through an already scarce sweet potato crop, therefore diminishing its storability, fills me with insecticidal cravings. There's no wireworm problems in my first allotment, so my crop placement choices this year have been highly unfortunate to say the least.

It's not all misery and desperation though. So far I've counted 8 sweet potato varieties producing flowers. These are Murasaki, Georgia Jet, Bonita, Asian Yam, Kalebe, Burgundy, Nordic White and Nordic Purple. That comes down to 7 European/commercial varieties and 1 African variety, which is in line with what could be expected. Heirloom varieties seldom flower (at least outside of the tropics) because of a long history of vegetative propagation, while commercial varieties tend to descend from flowering plants simply because breeders need seeds to work with and thus select for florescence. That there's one African variety (Kalebe) flowering is quite exciting, so I'll try to pollinate it or at least keep it alive over winter if I don't get any roots. Possibly more varieties will follow as the days shorten (some sweet potatoes are daylight sensitive for flower induction). I'm seeing very few pollinators around the flowers, so of course there's no guarantee that there'll be seed. In fact, I've yet to see a seed pod forming, but I've marked some buds that didn't fall off immediately.. where there's ribbon there is hope! I might as well increase the hand pollinations too, I've had less time for that than I would have wished so far.

Kalebe flower

On a final note, I've recently been reading Ken Allan's excellent book 'Sweet Potatoes for the Home Garden; with Special Techniques for Northern Growers', which summarizes his experiences with growing sweet potatoes in Canada. Apart from repeatedly stressing the importance of using a plastic mulch to warm the soil (meh!), Ken recommends Georgia Jet as the variety of choice in colder climates. This was interesting to me because Georgia Jet by no means performed exceptionally well here last year. I got no roots at all and had to keep it alive as a cutting over winter, though admittedly I did plant it somewhat late. This year, Georgia Jet has been one of the least vigorous of all the varieties I planted. I don't know if this is because of the quality of the cutting, or because I maybe have a diseased specimen, but the two plants I have don't amount to more than a few spindly vines. It does, however, flower profusely. I've received my Georgia Jet from Frank van Keirsbilck, who has also been having some problems with it, so I was kind of bemused to read the lavish descriptions of Georgia Jet in Ken's book. Maybe I need to locate another source of it, just to give it another go.

I wouldn't mind that Indian summer now...

Ode to a (lot of) cucurbit

Let's do a little quiz. What food is highly nutritious, productive, easy to grow, stores for months at room temperature, and tastes fantastic? And what food is highly underrated, wasted in copious amounts during the holiday season, and often reduced to its decorative qualities? I guess this really isn't much of a challenge for most of you... It's the winter squash of course!

Before I go any further, I should probably declare my bias and confess to a rather serious obsession with growing winter squash. In fact, this blog might equally well have been titled 'the cucurbita gardener'. Winter squash is one of the first vegetables I started growing and I consistently dedicate a quarter of my allotment to it. Last year I had the ambition to grow one squash for every week of the year and very nearly made it. Needless to say I was in over my ears with squash and as the winter progressed my skin was taking on an orange hue from all the beta-carotene I was consuming (a harmless condition known as carotenosis - I can recommend it as a healthy alternative to sunbeds, for the few of you concerned with your winter tan). Why this overt squash fetishism, you might wonder? Because it's such a fantastic food of course! A great winter squash is a rich, sweet and filling food that makes a very satisfying dish all on its own, as well as being an excellent addition to stews, stir-fries and a basis for all kinds of odd baking experiments. Furthermore, I aim to eat out of my garden as much as possible and in that respect squash is one of the more grateful crops to grow. It is fairly pest and disease-free here in Europe (apart from powdery mildew, which tends to occur only towards the end of the seasons and therefore does not really hamper fruit production), it's a storage champion, it's easy to save seed from, and it's a fascinating and beautiful plant to hang around with in the garden. What's not to like? It's a real mystery to me why winter squash is not utilized more. I suppose one reason is that a lot of the varieties out there are really not worth eating. I've had my share of bland, watery, and stringy squash, and it's easy to see how such experience could make anyone into a lifelong squash-skeptic. But there's really no comparison between the latter and a great winter squash at optimal ripeness, so please don't dismiss the whole squash family on the basis of a few of its inferior offspring! I guess you get the point, as far as I'm concerned, the neglect of the winter squash as a staple vegetable is a culinary tragedy waiting to be corrected.

The squash patch. It's seriously overcrowded, which I think is harming my yield.
Lessons learned for next year.

Any-way.. This year I'm deepening my winter squash commitment and I'm choosing quality over quantity. I've been reading up on so-called 'landrace gardening' in the past months and I've become convinced that this is the way I want to go, first and foremost for the winter squash, and then, hopefully, for a lot of the other vegetables I'm growing as well. If the concept is as new to you as it was to me, let me attempt a very basic summary... Most people (including myself) tend to buy their vegetable seeds from seed companies or, if they do save their own seed, aim to preserve existing varieties. If you do this, then essentially this means that you are working with the plant characteristics that others have selected for you. This in turn means that the seeds you buy and/or save are from plants that might be adapted to growing conditions very different from your own, including different soils and soil fertility, different (micro-)climates, different disease and pest pressures, etc. This is a perfectly good way to garden, but if you think about it a bit, it could probably be improved upon. Species evolve and environments change (not in the least, unfortunately, the climate...), so it actually makes perfect sense to try and work with these evolutionary pressures rather than against them. This is what landrace gardening (in the scientific literature it seems to be called 'evolutionary plant breeding') tries to do. The idea is that you grow out as many different varieties as possible (to maximize genetic diversity), let all of these varieties cross freely, grow out large amounts of the resulting seed, and then continuously select for the most vigourous plants that fit your personal preferences. The result, after many generations, should be your very own locally-adapted (and evolving) variety with high genetic diversity, and in possession of any of the traits that you have chosen to prioritize. Sounds great, right? I thought so too, so I'm set on testing this out on my winter squash.

I'm growing two species this year, cucurbita moschata (6 plants) and cucurbita maxima (21 plants). There are also some reputedly good winter squash among the cucurbita pepo's (I'm yet to be convinced of this..) but I tend to prefer the maximas and anyway, a lot of my neighbours are growing summer squash (which generally is also c. pepo) and this would make open pollination a bit difficult. There's a chance that the moschatas too crossed with my summer squash (damn you promiscuous squash!), so that leaves me with the maximas to save seed from (c. maxima doesn't normally cross with c. pepo or c. moschata... in theory). I started off with 7 varieties and plan on adding more genetic diversity over the next generations. For this year I've got:

C. Maxima - Sweet Mama

Sweet Mama: a hybrid that I grew last year and that I found to taste fantastic. It's nutty, rich, sweet, medium dry, and yields pretty well. This is also a semi-bush type plant so it's quite economical space-wise. Fruits are about 1-2 kg and mature early.

Sweet Meat Oregon Homestead: I haven't grown this one before, but the reviews I read were uniformly positive so I had to include it. Bred by Carol Deppe for reliability and production, It's supposed to be a great 'homesteading' squash with thick, very dry, and very sweet flesh. They can weigh up to 10 kg. I found it to be a bit slow-going compared to the others, and it seems to have characteristically rough leaves.

C. Maxima - Marina di Chioggia

Marina di Chioggia: An Italian heirloom that I grew last year and that I loved for its taste, which again is deliciously nutty and rich. It's a very vigourous plant that will take over your garden if you let it. It yields one to two large squash (up to 10 kg) with a characteristic dark green, bumpy skin, almost like a savoy cabbage.

Burgess Buttercup: An old American classic, reputed for its taste. I grew a buttercup variety before and frankly wasn't that impressed with the taste, so I'm hoping this one is quite different. The squash are fairly small and somewhat cubical, weighing around 1 kg.

Green Hokkaido: Supposed to be the same as Blue Kuri. This is my first year growing this as well. Actually my initial plan was to just use a select few tried and tested varieties for the start of my landrace project but the lure of new and exciting squash was too much to resist... This seems to be your average kabocha-type squash (which is just to say that it has Japanese origins), which are probably my favourites so far. It's green, sweet, and supposedly fairly dry. Medium sized fruits, 1 tot 2 kg.

C. Maxima - Galeux d'Eysines

Galeux d'Eysines: First year attempt at this one as well. It grows big (up to 5 kg) orange squash with a high beta-carotene content that form peanut-like warts on the skin upon maturing. From what I can tell it's really quite a fascinating sight. I'm mostly growing it for its supposedly excellent eating quality though.

Blue Ballet: This is a smaller version of the Blue Hubbard squash. I've been growing Blue Hubbard the past two years just because it's such an intriguing squash, but I've abandonned it since they never really stored that well for me (somehow, despite its armoured appearance, the Blue Hubbard was always the first to show signs of spoilage). They also seem to deterioriate in eating quality quite quickly, plus the seed cavity on these is positively enormous, making for a fairly poor flesh to overall fruit ratio. I grew Blue Ballet last year and found it to be superious in nearly every aspect: it keeps longer, it tastes better, plus the skin is actually edible, which in my book is a big plus. It's a vigourous grower that is fairly early and weighs about 2-4 kg.

Sweet Mama with Buttercup on top

So where am I going with all this fantastic genome? As stated, I've let the bees do their happy buzzing and am eagerly awaiting the approaching harvest. Upon which I will be storing the squash for a month or so (this maximizes their sugar content) and then dutifully embark on the (very pleasant) task of tasting my way through the squash stash to find the chosen few that I will save seed from for next year. What I'm selecting for is a medium-sized squash that is as dry, nutty and richly sweet as possible, that is highly reliable under my growing conditions (this should pretty much select itself), has an edible skin and a small seed cavity, and that stores well into spring. Next year's progeny will then probably be a mixed bunch, some of which will undoubtebly be fairly bad eating, but some of which should bring together the best qualities of the above varieties and provide the basis for a true Malmö winter squash landrace. Exciting!

37 shades of sweet potato

Back in the middle of June I planted out all my sweet potato starts out in the garden. I could surely have nursed some a bit longer but they were beginning to suffer indoors and, frankly, I thought that anything I planted after that day would have very little chance of producing tubers anyway. I was also struggling a bit with the logistics of it all and was eager to have them out there rather than being dependent on my undivided attention. I'll have to devise a better system for next year, though it might already help to have less varieties to sprout and keep happy...

I counted them after planting and ended up with a total of 37 varieties. In no particular order at all these were

12 commercial European/American/Asian varieties: 

T65, Nordic Purple, Nordic White, Nordic Orange, Burgundy, Bonita, Murasaki, Georgia Jet, Asian Yam 1, Asian Yam 2, Okinawa Purple, Garnet

25 (mostly) heirloom African varieties: 

Alira, Kalebe, Silek, Kanya, Uganda Orange 1, Uganda Orange 2, Kipapari, Mukekuru Tarya Bibiri, Tangara, Kitambe, Orphan, Rwabafurugi, Kitekyere, Mpame Hegia, Nyariowera, Kwezi Kume, Sula 1, Sula 2, Burundi, Bunduguza, Mushemeza, Kidodo, NASPOT 1, Bamuhachira, Magabari

A map of the 2015 batata garden

Some of these were not particularly viable though, and in some cases I just chucked a yet-unsprouted tuber in the ground, hoping that against all odds it would still do something. The amount of plants per cultivar varied a lot; of some I got 20+ plants, of others just one. This almost exclusively had to do with how fast the different tubers sprouted. For those that were very slow-going I ended up with few (or no) plants. By now some of these have quite definitely died, so I'm probably left with under 30 varieties.

Nordic Purple (left) and T65 (right)

It's been my luck of course that, exactly in the year I'm embarking on this grand sweet potato experiment, we're experiencing one of the coldest summers in decades here in Sweden. Except for a few tropical days in the beginning of July, the last few months have felt more like early autumn, with exceptionally windy, chilly and rainy weather. Predictly the sweet potatoes haven't been all too happy with this and growth is just a fraction of what it was last year at this point (though I was growing them under plastic then, so it's hard to compare). The optimist in me sees this as the perfect selection pressure and thinks that if any of these plants yields something this summer, it will reliably do so most years. My pessimist self on the other hand is quite convinced that I will end up with absolutely no sweet potatoes whatsoever. Either way I'm hoping that August will bring some direly needed sun for these:

Sula 1

Rwabafurugi

Nordic Purple

If I would formulate my ambitions, they would consequently be quite modest (or at least I think so..). I would like to get some kind of tuber from at least 3 of these varieties, plus some seeds. If I would have to choose, then I suppose the latter would be the most important, since it would make possible the long, very, very long, process of breeding nordic-adapted varieties. For that to happen I will first need some more growth and some flowers though.. Indian summer, anyone?

Please, world, make it happen.

From Amandine to Zillifera; an Andean summer update

It's high time for a brief update on this year's experiment with the Andean family of exciting tubers. Spring has been chilly here, with temperatures not much higher than 15°C for most of May and June, and the Andeans seem to have loved it. It must be that the wind and the cold reminds them of home. So far I have managed to keep all of them in reasonably good health with few if any casualties (that I recall..). I'm not sure how that rates as an indicator of gardening success but on a personal level it feels pretty satisfying.

Oca
Prematurely bereft of their identity, my blend of oca tubers has been growing steadily. Of the 30 or so that I planted I believe only four did not come up. The four plants that I had potted up in March have sized up considerably and over the past two weeks actually started flowering. Some days ago I noticed two other varieties doing the same, so I had a first go at oca pollination. Oca has a tristylous flower morphology which basically means that not all flowers are compatible (here is a more detailed decription) and you need flowers of two different types in order for succesful pollination to occur. I've yet to see if the flowers I pollinated are setting seed... The weather has actually gotten a lot warmer the past week, and oca seems to require fairly cool temperatures in order to flower, so I will probably have to wait until later this summer for more pollination opportunities. Pest-wise, oca has been fairly troublefree for me so far, the slugs don't seem too fond of it (they have decided to decimate my root parsley seedlings instead..) and not much else does either it seems. Some of the plants have some black aphid colonies but really nothing majorly worrisome. Oh, and after planting my first batch, I've received some more varieties courtesy of Rhizowen and his newfound Guild of Oca growers. These are 'brand new' varieties so it will be exciting to see what comes of them. Reassuringly also, I've managed to get these in the ground unshaken and correctly labelled. I might have a scientific career ahead of me after all.

Ulluco
If I can conclude one thing from my first year attempt at growing ulluco so far, it must be that it is really, really, really slow-growing. I thought I would lose these to the slugs at some point, since there seemed no way they could possibly outpace this year's onslaught of Arion vulgaris. Yet with a little help of some plastic bottles and my murderous garden scissors, they seem to have pulled through and are now... well, just standing there, really. I assume their growth will speed up at some point and who knows, they might even flower, which I will be eagerly looking out for (viable ulluco seed is very rare).

Ulluco

Mashua
Mashua must be something of the polar opposite of ulluco. It is growing faster than anything else in my garden and has already filled the space that I had intended for it. In fact, I found three of the mashua plants invading the oca patch the other day, and one of them was happily strangling one of the oca's. Safe to say I seem to have significantly underestimated mashua's territorial requirements... It's also remarkably pest free, I have yet to see a slug, snail or aphid show any interest in it. The only creature that did fall for mashua's undisputable charms was a rabbit, which promply munched down half of the 'white' variety but left the 'zilifera' untouched. It must have been on to something there.. Both plants recovered swiftly. Mashua is related to the garden nasturtium (Tropaeolum majus) and seems to have equally interesting flowers, so I'm looking forward to seeing those. I will have to wait until September though, since mashua normally only flowers with short daylengths.

Mashua, just before it got a bit out of control

Mauka
There's so much mystery surrounding mauka that this is easily one of my favourite plants at the moment. I've got two varieties growing, one red-leaved (which is either 'roja' or a red cipotato variety) and one that I grew from seed and is in all likelihood a direct descendant of the 'blanca' variety. These seem to be the only three varieties grown outside of the Andes at the moment. My objectives with it this year are first, to be finally able to taste it, which should be possible with the two plants that are in their second year now, and second, to somehow get it to produce seed. The latter will be tricky, since mauka apparently only starts flowering long into the European winter and is therefore very unlikely to produce mature seed before the frost kills it. I am planning to overwinter two plants indoors and hopefully can pursuade it to flower that way.

Mauka is fast-growing though not nearly as much as mashua. It has attracked a lot of aphids in my garden, with the result that all the growing tips have curled up. I assume this is slowing down the plant somewhat but it's still growing strongly so I see no immediate reason to start despairing. With the warmer weather of the past week, I'm also counting on increased predator activity to bring the aphid population back under control. Bring on the ladybugs!

Mauka blanca (?)

Aphid infestation in mauka growing tips

Quinoa
Ok, yes, so this is not exactly a tuber crop. It's all the more Andean though, so I propose that its inclusion here is fully justified. I'm trialling three kinds of quinoa this year, though I've had very poor germination with one and am yet to see if I will have any viable plants from that variety. I am also yet to be convinved that I'm actually growing quinoa and not the common garden weed lambsquarters (Chenopodium album). The two are closely related and plants look similar enough that I really can't tell them apart at the moment. I direct-sowed the quinoa in a place with plenty of lambsquarters, so the only real way to tell is to wait I suppose. I would be pretty excited to be able to grow quinoa, and going by ongoing attempts to commercialize it as a alternative agricultural crop in different European countries, this should not at all be impossible.

Quinoa (Chenopodium quinoa)

Potato
For good measure, and to do justice to the humble potato's origins, I'll include an update about this year's potatoes as well. I'm currently growing 7 varieties: Minerva, Juliette, Linzer Delikatesse, Amandine, Asterix, Arran Victory, and Mandel. I'm not exactly expecting a bumper crop since I planted them on a newly-dug piece of land that I didn't have time to prepare properly, but they should last for some months at least. I've since also read up on growing potatoes from seed ('commonly' known as TPS or True Potato Seed, as opposed to potatoes grown from seed potatoes, i.e. from tubers) and became sufficiently fascinated to put this on my (ever expanding) list of garden projects for next year. The idea is that, rather than relying on (disease-prone) tubers, you save the berries that (sometimes) form on potato plants and then grow those out to create your own locally adapted potato varieties. Incidentally, when I was thinning out the beets the other day I found one potato volunteer that must have come from one of last year's 'Sallad Blue' potatoes. Any potato that sows itself is a good potato in my opinion, so I'll consider that a humble start for next year's potato project!

Oca growing and the dangers of bicycle transportation

One of the root crops I'm trialling this year is oca (Oxalis tuberosa), an Andean tuber popular with fellow tuber enthusiasts but largely unknown with the potato-consuming crowds of Europe and North America (curiously though, it does seem to have established itself as a minor crop in New Zealand). Oca is an important staple in the Andean highlands, primarily Peru, Ecuador and Bolivia, and seems to have everything going for it: it grows fairly easily in harsh environmental conditions and poor soils; produces yields (potentially) rivalling those of the potato (at least in the Andes); and according to reputable sources (i.e. wikipedia) is a high-quality dietary source of potassium, vitamin C and iron amongst others. It is supposed to have the taste and texture of a potato, but with a lemony aftertaste (because of the varying levels of oxalic acid the tubers contain), though taste, along with colour, size, and yields in oca appears to differ widely depending on the variety. I wouldn't know to be honest, because I've never tasted one, but with some luck that's all about to change this winter. May this be my annum tuberosum!

I sourced some 14 (if I remember correctly...) different varieties past autumn, one of which came directly from Peru, and chitted them in egg cartons on my windowsill for a few weeks, much like potatoes, though these sprouted much slower. The Peruvian variety had started growing already when I received it and it was looking pretty shriveled by January so I potted up the tubers and grew them out on the balcony when it wasn't freezing. This is what it looked like back in April, just before I planted it out in the garden:

Oxalis tuberosa, var. 'annelotte'

The reports I read suggested that a lot of people pot all their tubers before planting them out but I had neither the space nor the patience for this, so I decided to give all the others the potato treatment instead and plant them out directly after my last average frost date. I thus meticulously labelled my egg cartons with the names of the different varieties and then, one sunny day at the end of April, packed everything into my bicycle crate and set myself on my way to the allotment. 

The science of egg carton chitting... here, oca and ulluco

I should have anticipated the result, for, notwithstanding this place being the Valhalla of bicycling, the road to my allotment is anything but even and I have over the years upturned plenty a plant start with what appears to be my excessively enthusiastic bicycling style. Anyway, suffice it to say that by the time I arrived, the oca's had been happily bumping all over their egg cartons, making my labelling efforts completely redundant and therefore putting a premature end to my intentions to systematically keep track of, and compare, the progress of the different varieties I have in my possession. Instead of making neat little variety-specific groups in the oca bed, as I had planned, I thus had to resort to planting everything at random. Please forgive me, Carl von Linné, but I suppose that as long as they grow well, I don't care so much what all of these were originally called. And grow they do, at least for the time being! With some exceptions, most of the plants have emerged by now, and they seem to be escaping the voracious appetite of the slugs in my garden this year. I wished that could be said of my Brassica seedlings, which keep disappearing overnight...

The oca bed, the four plants in front are the Peruvian variety
 that got a headstart on my balcony

Of course, in being so violently thrown all over the place, some of the oca also got separated from their sprouts. In a half-hearted attempt to make up for my foolishness I potted up these sprouts as soon as I came home and to my pleasant surprise almost all of them have since rooted. Some of these sprouts were really only half a centimeter or so tall, so these truly seem to be very resilient plants. Thus far this seems to be my kind of vegetable!

The sprouts that broke off easily rooted

What next? As most of the Andean root vegetables, oca is a daylight-sensitive plant and only starts producing tubers when days are short enough, sometime after the autumn equinox. In a frost-prone climate this essentially means that in order to get any kind of yield at all it's crucial to secure growth until well in November, which is far from impossible here in the Swedish south, but it's certainly not a given either. Oca enthusiasts such as Rhizowen and Bill Whitson are attempting to breed varieties that are daylight-neutral, and these are bound to pop up at some point (after all, the common potato started off as a daylight-sensitive plant as well), but until then, I suppose I'm facing the real possibility of an early frost killing all my plants before a single tuber has formed. At the other extreme, my plants might feel comfortable enough in their new surroundings to flower and produce seeds, which would allow me to do some oca breeding myself in the future. Fingers crossed!

An old woman can't eat two

A brief update on the sweet potatoes. I've got plenty of slips [basically tuber sprouts that one pulls off and then replants] ready to be planted out, but the potatoes and me are all waiting for the weather to turn a bit more friendly. It's been 12 degrees here, rainy and windy - very much the complete opposite of sweet potato weather - and the slips I condemned to my balcony for 'hardening off' are just sitting there with wilted leafs looking miserable. Nevertheless I'm gonna have a go at it pretty soon, I will have more slips than I will be able to use anyway so planting some out a bit early seems like a good way to test their adaptive capacities..

Sprouting in progress

Meanwhile I've made a list of the varieties that I have and that seem viable. Probably the number will change (hopefully in the upward direction) but so far it's 26 different varieties. Most of the names that I got are in different local African languages, and it's really quite a pity that I don't know the translation for all of them, seeing how original some of these names are. My favourite must be 'mukekuru tarya bibiri', literally meaning 'an old woman can't eat two', a name holding out the promise of fast-maturing tubers with corpulent qualities. Another good one is 'Orphan', denoting its alleged ability to feed large families. Here's the full list (with reservations for the spelling on some of these...):

Nordic Purple - offspring from my own garden, unknown original variety, purple skin and purple flesh, produced respectable tubers last year.
Nordic Orange - offspring from my own garden, unknown original variety, red skin and cream-coloured flesh. This one also produced some respectable tubers but got pretty devestated by the voles.
Nordic White - offspring from my own garden, sourced this in the US, maybe O'Henry? This one actually didn't do very well, either the voles got all the big tubers or I only managed to get a few small ones.
T65 - only variety that produced a respectable tuber without ground mulch last year, probably one of the most promising for my climate. Red skin, pale cream-coloured flesh.
Georgia Jet - I didn't get any tubers from this last year, but I have two cuttings that seem to be hanging in there so hopefully I can give them a another try.
Orphan - white skinned, allegedly named like this because it's a prolific cropper that will feed large families
Kitekyere - white skinned, long and thin tubers
Sula - red skinned
Bamuhachira - red-purple skin, with very dark purple sprouts
NASPOT I - improved African variety, light brownish skin and very white flesh that is extremely dry. This reminded me more of cassava than sweet potato when I tried it. Supposedly a good variety for processing.
Orange-fleshed I - 
Orange-fleshed II - light brownish skin
Bunduguza - white skinned variety
Tangara - copper skin
Kwezi-Kume - light purple skin
Kipapari - light brownish skin
Kitemere - white skin
Kalebe - copper skin
Mushemeza - Highland variety, grows at or above 2000m
Rwababurugi - Highland variety, grows at or above 2000m
Mukekuru Tarya Bibiri - 'an old woman can't eat two', according to the person I received this from this one should mature in 1 month, which is hard to believe but we'll see! Also a highland variety.
'Asian Yam' - I got this from a US supermarket, no idea what it is..
Alira
Kanya
Kitambe
Mpama-Hegia

Different leaf colours and shapes on 4 sweet potato varieties

In contrast to the varieties available in the US/Europe, most African sweet potatoes have white to pale yellow flesh and a very high dry matter content. Current sweet potato breeding efforts in many African countries concentrate on producing orange-fleshed varieties because these have much higher beta-carotene levels (a dietary precursor for vitamin A) than native white/yellow-fleshed varieties. American orange-fleshed varieties are regarded poorly by African farmers because people tend to prefer potatoes with a higher starch content, and from what I've read there seems to be some kind of trade-off between beta-carotene content and dry matter composition. I will be growing some traditional US orange sweet potatoes and some of the improved orange African ones, but most of the varieties here are the traditional ones with white and yellow flesh and all kinds of different skin colours.

Meet the last of my organic aphid control crew