Thursday, 9 October 2014

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!