Sunday, 16 January 2011

Checking and Storing Oca Seed Tubers

A typical Oca harvest is a bit like a '60s Terry Thomas film -  sure to contain the odd rotter.
Oca tubers contain natural fungicides, and have good resistance to moulds and rots, but if they have been exposed to frost there is no escaping the fact that they are doomed to smelly putrefaction (have a look), and while most of the obvious casualties will have been spotted early when the tubers were lifted and washed, there are usually a few with minor damage that sneak through.
So now, a week or two after harvest, it's time to recheck stocks for any smelly surprises before storing them away until Spring.
And yes, several tubers (those on the plate) needed to be binned. If I had been desperate, I could have sliced off the affected parts, dipped the cut surface in wood ash, and the remaining material would probably have been fine for storing and replanting, but I'm in the fortunate position of having enough tubers.

As I sorted through, I was also carefully checking for any colour mutations, and when I saw the tuber below, just for a second I thought I had the potential to propagate a piebald strain.

Superficially, it looked like the area around one of the eyes had mutated to have black skin -  similar to the black Oca I obtained in the autumn.

But then I spotted an entry-hole leading to this tunnel. I think it's probably wireworm damage. I did notice one making a swim for it when I was washing the tubers.

With all the baddies removed, It's just a matter of selecting the good sized tubers, and putting them into storage. I use egg boxes (with lids closed to reduce drying out) as it helps to keep things organised, and makes occasional inspection easy...
...but the tubers seem to remain viable no matter how badly they are stored over winter; if left uncovered in a  heated room, they will shrivel up, but they will still sprout when the time is right.
If you are fussy about maintaining the visual appearance of the tubers, then aim to reduce the rate of moisture loss, for example by wrapping in newspaper, or a paper bag, or covering with almost-dry sand or sawdust, and placing them in an unheated room, or frost-free shed.
Be aware that if you go for the shed option, mice can develop a taste for them.

I'll start checking for shoots sprouting around late March.

Thursday, 6 January 2011

2010 Oca Crop - Harvest

In agriculture there is always a 'right time' to do things, but even with hindsight it would be hard to define the best time to lift the Oca this year. Getting a balance between delaying harvest to maximise tuber development, versus lifting early to avoid damage from frost is a difficult call at the best of times, but this year it was always going to be wrong; with a very early first-frost in October, and a record-breaking cold spell in December, this was not an 'Oca-year'.
The top growth has been dead for several weeks now, but harvest has been delayed either by snow cover, sub-zero temperatures, heavy rain, or pessimism-induced lethargy. However, the snow cover has been the saviour of the crop... has insulated the ground during the really cold spell, so most tubers have escaped damage.
Tubers are generally small, and yield is well below that of previous years, but a few plants have produced a reasonable crop, while a couple have failed to make any tubers at all.
The unfavourable conditions have at least acted to highlight the productivity differences between varieties.  My planting stocks have been maintained, and there are enough extras for swapping and eating.

So a bad year, but mustn't grumble.