Potatoes – Chitting and Forcing

My seed potatoes finally arrived last week about a month later than I would have liked. I ordered Sarpo Mira for my main crop potatoes and Pentland Javelin for a first early crop which I was hoping to be able to harvest in May – probably a bit late for that now unless I try forcing – more on that method later…Maybe next year I’ll try pick up the varieties available in local garden centres rather than being too picky and relying on mail order!

Anyhow I wanted to get my potatoes off to an early start by chitting them.

What does chitting potatoes mean?

Chitting potatoes is a method used to give your seed potatoes their best possible start and is supposed to give a larger, healthier and longer crop of potatoes. Rather than immediately planting your bare seed potatoes; place them in a cool but frost free sunny place, such as an unheated bedroom, enclosed porch or windowsill. If you are only planning on planting a few potatoes you can prop them up singly in egg boxes with the blunter end containing the most “eyes” facing upwards as these “eyes” will develop the desired shoots; otherwise if you are planting lots of potatoes simply spread them out in a shallow box – the shoots will form anyway. After a few days you will notice tiny green protrusions emerging from the eyes – over the next couple of weeks these will develop into chunky green shoots. Once the shoots are an inch long your potatoes are chitted and ready for planting out.

Top Tip

Before planting your chitted potatoes, break off all but three or four of the green shoots – if you leave too many shoots on each potato the increased competition for space and nutrients will result in smaller lower quality potatoes.

Forcing Potatoes

Since my first early Pentland Javelin seed potatoes arrived late, in order to force them to crop in May I’m going to have to ensure they are in a warmer growing environment than is normal. To achieve this I will use compost bags turned inside out so that the black interior is now on the outside and ready to absorb as much heat as possible.

I will roll the bags down to half their height and fill them to a height of 12 inches with a mix of compost and regular soil. Once I have planted the potatoes I will add an additional 6 inches or so of compost. Within a couple of weeks shoots should have started to appear and once these shoots are 5 or six inches tall I will roll up the sides of the bag and fill with more compost until they are covered. I will continue to do this until the shoots reach almost to the top of the sack when I will leave them to flower. They should flower in May if I follow this method correctly and my potatoes will then be ready for harvesting.

This method has an additional advantage that the potatoes can be harvested as needed – a few at a time – whilst leaving the haulms to grow more potatoes for next time. Simply cut a small hole in the sack and pull out your potatoes as and when required without uprooting the whole plant!

Top Tip

Pierce a few holes for drainage in the bottom of the sack and keep the soil moist but not soaking. Try to keep the potatoes growing in a warm greenhouse to make the process as quick as possible


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