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What are seed potatoes

01:00 Thu 24th Jan 2002 |

A.� Seed potatoes are specially grown tubers saved from last season's crop. Like seeds they are sown to produce this year's crop.

Q.� What is to stop you just saving some of your own crop and using them the following year

A.� It can be done, but certified seed potatoes have been grown in areas where aphids that spread potato diseases are less of a problem and are much, much more reliable.

Seed potatoes are, or should be, smaller than your average potato because larger potatoes produce too many shoots to produce a good crop. They're not that expensive either.

Q.� There are lots of different varieties grouped together under headings like First Earlies and Main Crop. What is that all about

A.� It just refers to when they mature. First and Second Early varieties are usually ready to dig up and eat between June and July whereas Mains mature later and are generally ready between September and October.

Q.� Garden centres and nurseries are selling them already. Surely it is too early to plant them

A.� It is, but you don't just whack seed potatoes straight into the ground. First you need to 'chit' them. Planting takes place between March and April, depending on where you are and the variety.

Q.� What is chitting and how do you do it

A.� Chitting is a process whereby you get the seed potatoes off to a start before you actually plant them. This is particularly important for early varieties as they have a relatively short growing period but you can it is also done with Main variety tubers in areas of the country where they need to be planted as late as possible to avoid frost.

A month before planting, place the tubers 'rose' end - that is broad end - up in a light airy room. You can stand them in a box, seed tray or even egg boxes.

The buds on the tuber will sprout and are ready to put in the ground when they are about an inch long. If you have lots of sprouts, nip off the weaker ones to leave four of five of the strongest.

Q. How should you prepare the soil for potatoes

A.� One of the reasons they are so widely grown is their ability to grow in pretty much any soil and that they will grow in 'dirty land', where other things won't, given enough manuring.

The ideal is a free-draining, deep soil with lots of organic matter mixed in, but don't worry too much if your soil doesn't quite fit the description. Don't add lime as they prefer a nominally acid soil.

What you do need is a fine tilth, as after the shoots emerge you need to earth them up, that is create a ridge of soil about six inches high over them.

Particularly if you have a heavy soil, start digging over the ground, allowing the frost to break up big clumps and regularly fork it over and rake to get a crumbly, fine topsoil.

If you forgot to add manure or compost to the soil in autumn don't despair. Add some well-rotted organic matter to the bottom of the planting trenches (about six inches deep). It will get them off to a good start and help retain moisture.

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By Tom Gard

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