To chit a potato means to start it into growth before planting, in order to reduce the time it takes to be ready to crop. There are several benefits:
Earlier Cropping - The benefit of an earlier crop is that you can stop buying potatoes earlier, and can probably crop over a longer period, so reducing the impact of a glut of potatoes being ready all at once. You can also generally start to chit before you could plant in the open ground, so gaining a few more weeks of time. This is also a benefit if your ground suffers from pests that strike later in the season, or if you get blight in your area.
Improved reliability - you will see which are the most viable seed tubers and can plant these as a priority. Any that are weak or rotten can be discarded before planting. You can also remove some of the growth tips to concentrate energy into just a few large potatoes rather than many small ones.
Quicker to establish - you can encourage early root development which will mean that the potatoes won't sit in wet earth and potentially rot before they can establish.
The downside of chitting is that some people say you get a reduced yield, or overall crop weight. This is hard to determine at home, as so many factors affect yield in a given season.
Chitting is most commonly used for early potatoes, where the benefits of an even shorter time to maturity are realised. Typically though, it is normal for most potato types to be chitted.
Things You Will Need
- Your selected seed potatoes (from an online / mail order supplier, garden centre etc)
- A few seed trays, shallow cardboard boxes, egg boxes or similar to stand the seed potatoes in
- newspaper (optional)
- Labels, pen / marker
- A light, frost free place, preferably with a reasonably constant temperature, and out of direct sunlight
Selecting the seed potatoes
Once you have decided on the variety for your locality and needs and depending on where you purchase them, you may be able to select your own bag or individual tubers. Late Winter or very early Spring is the time to get them. You may have to place your order in the Autumn for sought-after, rare varieties. You should look for firm, fresh looking tubers that are not wrinkled, soft or smelly. Any fungal or rot damage should be avoided. For earlies, larger tubers are likely to perform better, but something the size you would expect to get as a potato of that variety is fine. Avoid excessively large or small tubers.
Checking the tubers before chitting
As soon as possible after receipt or purchase, get the tubers out of their bag and examine them closely. This is essential if you haven't been able to select your seed potatoes yourself, as there is likely to be a short period where you can make a complaint to the supplier if you are not happy with the quality. Again, you need to be vigilant for rot, as this will contaminate the next potato to it, and you could soon end up with a pile of mushy, smelly sludge. Once you are happy with your tubers, it is time to set them in their trays to chit.
Identify which way up they should go
Start with the best looking tubers, and notice which end is the 'rose' end. The rose end should be the end with most eyes, and ideally with very small shoots starting to form. (See photo, here of Charlotte, a second early salad variety). It is sometimes hard to tell the difference between the ends of the potato, but as long as you can see some eyes starting to sprout, you are not going to go wrong. You might find that the rose end is also slightly more bulbous than the other end, which may help you identify it.
Add a dated label so you don't forget which variety it is and when you started, and place it into a light, frost free place. A windowsill in an unheated porch, or if your shed or garage has a window, would be fine, or you could use the greenhouse benching. Leave them for about 4-6 weeks, or until you have shoots about 25mm / 1 inch long. Check them from time to time to make sure there is no rot, or damage from mice. When the weather is suitable, and you have prepared your ground, you can plant them in the vegetable garden following another 'How to guide'.