Seed potatoes are placed in the ground after the soil will reach about 10 Celsius degrees (50 F). To speed up the process you can chit your seed potatoes. Chitting is a technique of preparing potatoes for planting by placing them in trays or in egg cartons, in a light and cool place but protected from frost, for several weeks, to induce sprouting. A night covering of straw or newspaper strips will offer frost protection. Sprouts can be green or purple, depending on your seed potatoes type.
This technique, also called greensprouting, can reduce the time from planting to harvest by 10 to 14 days, giving your crop a head start and helping you to take full advantage of the cooler days of spring and early summer, similar to germinating your seeds under protection before planting them out.
Potatoes are not hardy and are prone to blight. Chitting your seed potatoes you are giving them a good chance of survival once they are planted. This technique also gives you a chance to remove any diseased tubers and to reduce the number of sprouts on each tuber to encourage larger potatoes. Start the chitting process about four to six weeks before you expect to plant them out. When the sprouts are about 2.5 cm long and the soil is warm enough, the seed potatoes can planted out in the ground by spacing them about 5-8 cm deep and 30-45 cm apart.
After chitting your seed potatoes you should get more than one sprout per potato. To maximise the size of the potatoes in your crop, you should remove all except the two or three strongest sprouts per seed. Large seed potatoes, with more than 4 sprouts can be cut in half, with two sprouts left on each half, so you can choose to plant whole potatoes or you can cut each seed piece into two making sure each piece contains at least two eyes.