Saturday, 30 January 2010

Oca versus Frost

I always like to have a nice photo to illustrate a post, but this time, viewers of a nervous disposition should look away.
The photo shows Oca tubers slightly, partially, and completely damaged by the recent period of sub-zero conditions. It seems that the frost has penetrated 50 to 70 mm below the soil surface, causing quite a few casualties - around 20% of tubers had to be discarded. Affected tuber flesh looses its colour and crisp texture, taking on the appearance of clammy rubbery white maggot flesh. Within a day or two a characteristic smell of decay appears, and the maggots are on the way to becoming biological soup.   Some might attempt to turn this into a delicacy, but not me.

According to Lost Crops of the Incas... " Farmers mound dirt over the base of the plants to encourage stolon formation". But stolons aplenty appear without earthing-up, so maybe a more important reason is to protect tubers from frost once the stems have died back.

Hard or prolonged frost is unusual here in West London, and I consider this year's cold snap a rare event, so do not plan to routinely earth-up Oca crops in the future. Quite apart from the extra work involved, it would be awkward in most bi-crop situations, and it goes against my preference for minimum-tillage cultivation.

Anyhow, plenty of tubers escaped damage...

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