Our gardening expert on the case for chitting spuds before planting them
It is most likely too late to debate whether to chit or not. Across the land, egg boxes are full of sprouting potatoes willing on the first good days of spring. There is something so pleasing about those little fat shoots appearing at the end of a tuber.
The idea is to develop the chits (shoots) on the seed potato before it is planted out, to speed up growth so you can harvest your crop three to four weeks early. If chitting speeds up growth at the beginning, it also hastens the end with the onset of senescence – and this can do quite the opposite to what’s desired. It can reduce yields. The trick is to keep those chits as healthy and chubby as possible.
In reality, you often don’t get to choose. Early potatoes, in particular, can’t wait to get sprouting. If you keep your tubers in a warm room, where chits will grow fast and furiously, they will be pale and easily damaged when planted out. Worse still, the shock from a cosseted warm room to the cold, hard world of outdoors can slow the plant’s growth.
So you need to keep your potatoes somewhere cool, but frost free – in the region of 10-13C will do the trick. Equally, they need good light conditions, but not direct sun, so that the chits grow fat and green, rather than pale and lanky. Ideally, they should be about 2.5cm long at the time of planting out.
If your shoots are growing too fast and your tubers start to become wizened, move them to a cooler position. Once the sprouts appear, spray them with diluted seaweed fertiliser every 10 days.
The number of sprouts on a tuber determines the size of your crop. If you rub off the side sprouts and just keep the ones on the rose end (the top end of the tuber), you will get fewer, larger tubers.
If you leave all the sprouts on and plant the tubers on their sides, you will get numerous, smaller potatoes. Consider whether you want to harvest your potatoes for salad or produce a crop for baking.
However, it’s not just chitting that brings your crop forward. The temperature of the soil at the time of planting plays a role; you can ensure it is warm enough by covering it now with black plastic, cloches or a layer of dark compost or mulch. Soil temperature needs to be above 6C for three consecutive days before the chits go into the ground.
Traditionally, planting the chits is done on Good Friday so you’ve got plenty of time to start warming up your chosen planting spot.