How does it work?
You may have had the experience of potatoes you have bought to eat sprouting in their bag - if they are in the dark these will have been long white stems coming out of the 'eyes' of the potatoes.
Deliberately chitting them is a similar process, but is done in the cool and light so that the streets are short, green and raring to grow once you plant them.
How do you do it?
Start chitting your potatoes about 7 to 9 weeks before the last frost in your area. Here in Stirlingshire the last frost is the middle of May, so I begin chitting potatoes in the first half of March. This allows for 4 weeks chitting and then 4 weeks growing up through the ground (before the leaves become vulnerable to frost).
Take your potatoes and stand them on end in a shallow box. Try and put the end with the most 'eyes' facing upwards An egg box is perfect for this but you can also use a seed tray or similarly shaped box and make dividers from folded newspaper.
Put the potatoes somewhere cool and light - it is very important that they don't get frosted but equally you don't want them to grow fast or dry out. 5-10 degrees is ideal, a frost free greenhouse, an unheated bedroom, porch or by a shed window may all work.
When you plant the potatoes - 4-5 weeks before your last frost day - rub off all but 4 of the shoots with your fingers. This will give you a better crop than leaving them all on.
Plant with the shoots facing upwards.