Cutting seed potatoes is a way to increase the number of potato plants grown from one seed & is used when the seed of a particular variety is scarce or very expensive.
Large seed potatoes may be cut into several pieces, as long as each piece contains at least one eye. The ideal seed potato is the size of a hen’s egg.
The eye of the potato is a leaf scar with a depressed lateral bud. This bud will grow into the shoot, which appears above ground, and also produces the new tubers below ground. When the eye first starts to grow the new shoot is called a chit.
Kestrel Potato showing Eye
How to Divide, Cut or Split Seed Potatoes:
- divide potatoes a day or two before planting, so they have time to heal
- use a clean knife, to prevent spreading disease from one potato to another
- cut when sprouts/chits are 1/4″ long pieces should be about the size of a small egg.
- cut pieces should be block shaped, with at least one eye or sprout, but two are preferred. Thin slices of potato are no good.
- cut lengthwise, across the top, to divide the chits that usually group there.
maris bard potato chit
- part of the centre core of the potato should be in each piece.
- cover the cut potatoes with powdered limestone, to dry the cut up. Or sprinkle with flowers of sulphur, to stop any disease entering the cuts.
- let the potatoes “heal” by storing them at 65-70 degrees with fairly high humidity. The humidity is important to stop the potatoes dehydrating. The cut surface will develop a protective coat that can help prevent seed decay. Covering the box with clear plastic film will also stop dehydration.
There are pros and cons to cutting seed potatoes into several pieces before they are planted:
The advantages of splitting seed potatoes are:
- large seed potatoes are utilised to the full
- less tubers are produced per seed, so each tuber harvested is bigger
- apical dominance is broken, releasing more eyes to sprout
- expensive seed potatoes go further in the vegetable garden
- saves buying another packet, if just need one more seed to finish the row
Disadvantages of dividing seed potatoes are:
- bacteria & pathogens may be spread between the potatoes on the cutting knife.
- Large seed potatoes may be divided up into several pieces, as long as each piece contains at least one eye, to achieve the ideal seed potato size, equivalent to a hen’s egg.
Larger seed potatoes:
- have more vigour
- grow quicker
- emerge sooner
- will be ready for harvest earlier
- for more information click size of seed potatoes
Cutting seed potatoes is an old technique which has been practised by vegetable gardeners for years.