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

Early spring musings...

My windowsills are filling up with pots and seed potatoes, seed packets are scattered all over my table and the balcony is slowly being colonized by obscure roots. It must be that time of the year again! It’s starting to look a lot like spring here, or at least it feels close enough to get carried away dreaming about the coming growing season. Here’s a brief rundown of this year’s projects:

Sweet potato galore

    I’ve collected different sweet potato varieties over the past months, including quite a few that reportedly grow at 2000+ meters. My hope is that I will stumble across a few varieties that could (potentially) produce a worthwhile crop here in Sweden or, failing that, that I can get some plants to set seed with which to breed. Sweet potatoes don’t produce seeds easily, and the key (apart from some very un-Swedish climatic conditions, needless to say), seems to be genetic diversity, which I should be able to provide. There were 40+ varieties stored in my apartment at some point but quite a few of them succumbed to dry rot while I was out of the country, probably because storage temperatures dropped lower than I had anticipated, and sweet potatoes really hate cold storage. I guess I’ll just consider this as a first evolutionary pressure selecting for cold-tolerance! It’s yet to be seen how many of them I will get sprout successfully, but so far it’s 18. Whether I can make it warm and cozy enough for them long enough is an entirely different matter of course…

Mauka take two

    Last year’s mauka crop was not much to write home about. I’m not one to give up easily, especially after seeing what Frank Van Keirsbilck’s maukas look like, so I’ll be replanting the overwintered roots as well as some of the cuttings I took in November. The roots already started sprouting so if anything I’ll struggle to keep them under control until they can go into my garden. I’ve also got my hands on some rare mauka seeds, so if all goes well I’ll soon have some new varieties to play with! To be continued.

 Invasion of the Inca crops

This year will also mark my first year growing oca, mashua, ulluco and quinoa. If you think trying this many new crops all at once is pushing my luck a bit, you are probably correct. I am most excited about oca (Oxalis tuberosa), which in the Andes is second in importance only to potatoes and which amateur growers here in Europe generally seem to lavish with praise. As with most Andean crops, oca unfortunately needs short daylight hours and at higher latitudes therefore only starts producing tubers after the autumn equinox. People like Frank van Keirsbilck and Rhizowen are trying to rectify this injustice by breeding a daylight-neutral variety and if I manage to cajole my future crop into producing seed for me I will gladly join this guild of oca growers. Mashua (Tropaeolum tuberosum) and ulluco (Ullucus tuberosus) have received slightly less ravenous reviews but I’ll judge them when I’ve tried them. Most people these days are familiar with quinoa (Chenopodium quinoa), that Andean staple food-gone-global that has become the darling of hipsters and foodies. Prices for quinoa have in recent years risen to such astronomical heights that those in the Andes who used to rely on the crop can no longer afford it, so what better thing to do than grow your own!  Quinoa is one of the few (pseudo-)grain crops that yields acceptably even on smaller scale, and I’ve collected some varieties that have been selected for northern, wet climates so as to minimize the (considerable) chances of end-of-season disappointments and depressions.

Oca in close up, it started sprouting spontaneously

Ulluco (Ullucus tuberosus) - this must be one of the most beautiful root vegetables out there

Landracing my wintersquash

In past years I’ve been on a quest to grow and sample the world’s variety of wintersquash. Honestly, this must be one of the most underappreciated crops out there. Incredibly easy to store, nutritious and delicious, it’s simply mind-boggling that the main purpose we’ve come up with for this amazing food crop is as a Halloween decoration! A staggering 95% of all pumpkins grown in the UK are used for carving and hollowing each year, amounting to enormous amounts of food waste. The humble pumpkin deserves so much more! It matters enormously which variety you grow though, and many do taste bland and uninteresting and frankly are of little culinary interest. But there's so many truly fantastic varieties that we could be growing instead.

Essentially the squash family is made up of three commonly eaten species: Cucurbita pepo, Cucurbita maxima, and Cucurbita moschata. C. pepo includes most of the varieties that we eat in the form of summersquash as well as what are traditionally referred to as pumpkins. It is these that are usually carved up for Halloween lanterns. C. maxima includes winter squash of various colours and sizes. They usually do quite well in temperate climates and are completely underutilized here in Europe. C. Moschata includes the well-known butternut varieties and is very productive but it tends to require more warmth than C. Maxima and is therefore more difficult to grow here in the north. After three years of squash growing I’ve come to realize that I’m a C. maxima kind of guy. The best maximas are smooth, incredibly rich in flavour, nutty and sweet and in my opinion far outshine even such C. pepo favourites as 'sweet dumpling' and 'delicata squash'. This is why this year I’m abandoning my C. pepo (except the summersquash varieties) and launching an attempt to create my own C. maxima landrace variety that should bring together the best of ones I've sampled.. I will be selecting for a medium-sized, dry-fleshed variety that is nutty and rich in taste, has edible skin and stores forever. More details soon! I’ve never really tried to grow C. moschata, so that’s on this year’s list as well.

Expansion of the perennial patch

A small section of my garden is currently dedicated to perennials and this area will be expanded/filled in more densely this year. For example, I’m once again trying to pre-grow cicily (Myrrhis odorata). In past years I’ve tried seeds from three different seed companies and for some reason I haven’t gotten a single seedling yet, despite scrupulously following stratification instructions. This year’s seeds have been outside the whole winter but no signs of life yet. I’ve also started various other perennial greens and herbs, including bunias orientalis, mountain mint (Pycnanthemum pilosum) and mitsuba (Cryptotaenia japonica), and I will be planting some perennial kale (Daubenton) and some yams!

And then, of course, there’s also a host of smaller projects, such as trialing a host of new greens and testing a variety of new potatoes, but I’ll spare the details of that for now.

Mauka meets Sweden, take one

I was not actually being very correct last time when I wrote that my tuberous adventures in 2014 were entirely restricted to sweet potato cultivation. There is one other rather exotic crop that I got my hands on this year. In fact, this is probably one of the most exotic tubers out there, eclipsing the humble sweet potato by lunar magnitudes. I am speaking, of course, of mirabilis expansa aka mauka, miso or chago, an Andean root vegetable that is as deliciousy mysterious as its multiple names suggest.

Mirabilis expansa

Since my ambitions in growing Andean root vegetables far outweigh my patience in actually acquiring the plant material, I have recently gone ahead and purchased Lost Crops of the Incas, the 1989 standard work for aspiring cultivators of unusual and long-forgotten plants from the Andes. The book contains some intriguing facts about mauka. Believed to have been a staple crop of the Incas, mauka was completely unknown to scientists (a fate that many an animal and plant species would probably benefit from) until the beginning of the 1960s, when it was found being cultivated in remote parts of Ecuador, Bolivia and Peru. Growing at altitudes above 2700 meters, it is said to be particularly tolerant of harsh conditions, which of course makes it a promising plant to try in more Northern latitudes. Its alleged ability to grow to mythical proportions over the course of one or sometimes multiple seasons (it appears to be a perennial though its frost tolerance is uncertain) has inspired some people to describe it as some kind of Andean cassava. Frank Van Keirsbilck told me they tend to weigh 800g to 2kg after one growing season in his garden. As most tuber crops, mauka is believed to be very nutritious, and, more importantly perhaps, is also reported to be delicious. Descriptions on the internet place the taste somewhere in between potato, parsnip, and sweet potato. Now, these just happen to be three of my favourite foods in the world, so there was plenty of reason here to make me very excited indeed.

Harvesting mauka

I was then quite pleased last spring when I managed to acquire two cuttings of the CIP208001 variety (courtesy of Rhizowen, and actually also of Frank, who is the original source of the plant in Europe and who also sent me cuttings, though these didn’t survive the onslaught of the Belgian/Swedish postal system). Since this was probably one of the first times that mauka graced these parts of the world with its presence, I first pampered the cuttings on my balcony until they seemed strong enough to stand their own in the real world. For space reasons (read: I’m horrible at planning) they ended up in the border of my garden, where they soon took off and seemed happy enough. Nothing really seemed to disturb them very much, not even the vole invasion in the nextdoor sweet potato patch or the biblical floods in early autumn that temporarily turned my garden into an miserable wetland. Though apparently not daylight-sensitive like many other Andean crops, Mauka roots seem to bulk up fairly slowly, and it was therefore good fortune that the first frost came fairly late this year, just a few days ago in fact. The frost was very mild and killed just the top leaves, leaving much of the foliage undamaged, so I could probably have left the plants in the ground for a while longer. Impatient gardener that I however am, I didn’t want to wait any longer so I harvested the rest of the leaves for salads and ommelette-fillings (and pretty tasty they were too!) and dug up the roots. Amazingly, I already found some new growth sprouting from the top of the roots, so this certainly is a plant that wants to grow.
    

The two underwhelming tubers... on a piece of A4...

I hope this does not turn into a trend on this blog, but the harvest, dear reader, was not exactly something to write home about. The two tubers weighed about 150g each. My plan was to eat one, and save the best one to resprout next year, but at 150g that seemed somewhat premature to say the least. I’ve therefore postponed the taste test to next year and stored both of the roots on my unheated attic (for lack of a better option), where I hope it will be cold enough to keep them from sprouting too soon. I’ve previously also taken a dozen or so cuttings that are happily growing new leaves at the moment, and I have received at least one new variety (mauka blanca) to try next year. Together this should give me plenty of plant material to carry out a proper trial next year, in the absolute best spot my garden has to offer. It’s all uphill from here for mirabilis expansa!

The 2015 mauka babies

A whole lot of could’ve been…

Yesterday was the day that I could no longer contain my impatience and finally dug up my sweet potato plants. The temperature had already gotten dangerously close to freezing one night in September, and since tuber growth apparently slows down significantly below 15 degrees, I figured there was no point in delaying further. The two rows I planted (about 25 plants in total) had been in the ground for well over 4 months, which should be more than sufficient time for the roots to size up to positively monumental proportions. Indeed I would be lying if I said I was expecting anything else. As I made my way to the allotment for the first time in over a month, I was picturing the mountains of sweet potatoes that I would be excavating. Tubers the size of melons there would be!

Cleaned out pretty thoroughly...

The sorry state of some of the plants should have forewarned me of the gloomy scenes to follow. Instead, I imperviously checked on the rest of the garden, harvested some late winter squash and dug up some potatoes before directing my attention to the sweet potato patch. I shrugged off the dying foliage on the plants in the first row as end-of-season fatigue and carefully set myself to removing the plastic mulch and laying aside the vines. The first thing I found there was a vole, fat and recently deceased, presumably, I now surmise, from gluttony. Under the first plant were the leftovers of its last supper: a sorry bunch of eaten-out sweet potato skins, which, from the size of them, hinted at the once substantial tuber that must have been here. Undaunted, I quickly proceeded to the next plant, only to find the same scene repeated here. I felt a slight depression setting in as I continued to make my way through the patch. Plant after plant revealed the remnants of a feast made for kings. My awe for the voracious appetite of the resident rodent population was overshadowed only by my despondency at the sight of it all. As careful excavation made way for feverish, incredulous digging, my garden fork inadvertedly pierced some of the tubers that the beasts had neglected. O cruel, cruel world!

Not exactly a melon, but close enough!

All in all the voles devoured at least two thirds of the harvest. They seem to have taken a particular liking to the orange-fleshed varieties, of which not a single tuber survived the onslaught. I was able to rescue a few handful of the purple-fleshed and white-fleshed/purple-skinned varieties, some of which indeed sized up quite nicely. This and the size of the eaten-out skins suggests that it’s certainly possible to grow sweet potatoes in southern Sweden outside a greenhouse. While the plastic mulch undoubtebly played an important part in this, it probably didn’t do the vole activity any good, what with sheltering them from rain and predators and all. The row with the latecomers that I planted without plastic seems to have been spared. Here I found some small T65 tubers, at least enough to produce slips next year and give them a properly timed trial. I left some of these plants in the ground for now, perhaps they will bulk up a little more before it freezes.

This is the full extent of undamaged tubers. I also scavenged some half-eaten ones.

As winter draws near I will have plenty of time to brood on a battle plan for next year. It might be that I simply need to harvest earlier, since the tubers seem to have developed properly before the voles got to them. Or it might be that I have to abandon the mulching and leave the plants to fight the Scandinavian weather on their own. While this would make root development much more uncertain, it would certainly impose selective pressure for adaptation to Swedish summers on next year’s crop. I am somewhat ambiguous about taking this step, since I don’t mind some climatic cheating if it brings closer the possibility of some day harvesting those melon-sized tubers. After all, as much as I am eager to find those temperate-climate adapted varieties, I also have the more mundane question of my dinner to think of. To mulch or not to mulch, that is next season's question. Whatever it will be, I will likely have plenty of genetic diversity to work with. I managed to obtain an additional 23 African varieties of sweet potato over the past months, all of which I hope to trial next year, provided they make it through the winter. I might have the last laugh in this yet, voles!

23 genetically distinct opportunities for next year's attempt!

A sweet Swedish summer

Different varieties of sweet potato mingling

I have recently come to terms with my obsessive (if rather uninformed) pursuits in gardening, especially with respect to growing the more unusual, the not-so-adapted and the plain impossible here in the deep south of Sweden. Since I see no imminent end to this rather newfound passion of mine I figured I might as well make an attempt to systematize my efforts and along the way share some of my endeavors with anyone out there who might, just maybe, be interested. Hence the rationale for starting this ‘weblog’, I guess it’s as good as any.

While my ambitions for next year are great, the unusual, not-so-adapted and plain impossible this year mostly consists of a second-year attempt to grow sweet potatoes. I am tracking down and trying different cultivars in the hope of finding one or more that consistently produce reliably outside a greenhouse here and that happens to be delicious as well. Last year’s attempt produced a rather meager crop with the odd massive tuber here and there, but I had a late start and a lot of other excuses as well.  

This used to be two separate rows...

This year I’m growing 7 (or maybe more - I obviously have a lot to learn when it comes to botanical bookkeeping) different varieties. I have some Georgia Jet and T65, two early-maturing varieties kindly sent to me by Frank Van Keirsbilck. These are commonly grown in more temperate climates and should be able to produce quite well here. They got off to a bit of a late start this year though, so I’m not quite expecting a bumper harvest, but as long as I get enough tubers to produce my own slips next year I’ll be one happy man indeed. The rest is a bunch of unknown varieties that I collected from tubers in different shops here and there: 1 variety with purple skin/purple flesh, 1 purple skin/white flesh, 1 white flesh/white skin, and at least 2 different orange fleshed varieties. People who know me will readily affirm that I have an uncanny fascination for ipomoea batatas, so thinking about the day not so long from now when I will finally be able to lift all these beautiful specimens and see what they have been up to the whole summer makes me very excited indeed…

  

No seeds, but very pretty!

It has been pretty amazing sweet potato weather here this summer, with record-braking 30 degree temperatures, so I feel like I’m entitled to nothing short of an amazing harvest this year (uhum…). I planted most of the plants on a ridge covered with plastic mulch, and, in a somewhat ill-controlled experiment that included me forgetting to use the same varieties for both rows, then constructed a polytunnel over half of them and used a floating row cover over the other half, which I lifted fairly late in the season (end of July-ish), once the plants started to bulge out of the space they had been allocated. The polytunnel I left in place until late August, when I started to fear that the lack of space/increased rains would create rot on the vines. I also planted some latecomers, including the T65 and the Georgia Jet, in a separate patch without any mulch (I am, after all, looking for varieties that grow without too much pampering). If the foliage is anything to go by (and I know that it’s not), then the plants are doing great so far, with plenty of healthy growth. Two of the unknown varieties started to flower in the height of summer, and while I will probably have to store away my ambition of getting any seed for now, I have at least marked them as potential seed-producing contenders in some undefined future. All of the plants that flowered are in the space that had the row cover, so now I’m wondering if that might at all have played any role in inducing flowering. If anyone has any more informed theories about this, I’m all ears.