Plant Doctor Archive

 I LIVE in Whangarei and plant my potatoes about early Oct. I have been disappointed with the crop I have got of the plants so far. This year I used a seed potato ‘Ilam Hardy’ with plenty of sheep manure and blood & bone. My soil is mainly volcanic. Can you please make any ideas for a better crop? Or is the wettish weather a factor?

 IT sounds like you are doing everything basically right. However, I do wonder if you are waiting long enough to get a decent crop. ‘Ilam Hardy’ is usually harvested in late summer rather than in December. If you want potatoes for Christmas (certainly a reasonable desire in my book), then I suggest choosing a different, earlier cultivar. Usually with potatoes, it is best to wait until the foliage has died down to get the best yield. Chances are that if the foliage is growing vigorously, it is doing so to feed the tubers below ground.

Potatoes are very sensitive to soil moisture levels. The wet weather should have kept things moist, but did they dry out at all? Lack of water during a dry spell can reduce the size and number of tubers you get.

You could also try an occasional foliar application of an appropriate fertiliser.

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