Is chitting potatoes actually worth it?

Chitting is starting seed potatoes into growth before they go in the ground. It is one of those garden traditions that is somewhere between useful and ritual, and it is worth knowing which parts of it actually do something, because a bad chit is worse than no chit at all.

Step by step

1. Set the tubers out as soon as you get them, in late winter.Stand them in egg boxes, seed trays or the box they came in, with the end carrying the most eyes uppermost. That is the rose end — usually the blunter end, opposite the scar where it joined the plant.
2. Put them somewhere cool, frost-free and light.A porch, a spare bedroom windowsill, an unheated conservatory or a light shed all work. Around 8–12°C is ideal. Light is what makes the difference between a good chit and a bad one.
3. Give it four to six weeks.You are aiming for sprouts about 2cm long, thick, stubby and dark green or purple. That is a shoot that will grow away immediately when planted.
4. Reject long white sprouts.Pale, thin, brittle sprouts mean the tubers were kept in the dark and too warm. They snap off during planting and the tuber has spent energy for nothing. Rub them off, move the tubers into the light and start again if there is time.
5. Rub off surplus sprouts if you want size over number.Leaving three or four strong sprouts gives fewer, larger tubers. Leaving them all gives more, smaller ones. For earlies eaten as new potatoes, leaving them all is usually what you want.
6. Handle them carefully at planting.Chitted sprouts snap easily. Carry them in the tray to the row and lower each tuber in sprouts uppermost rather than tipping a bag into a trench.
7. Do not chit if you are planting straight away.If the weather has already warmed and the soil is ready, planting unchitted seed loses you very little. Chitting is a way of using the waiting time, not a requirement.

Tips

• Chitting is most valuable where the season is short — a northern garden, a cold exposed site, or a container crop you want to eat as early as possible.
• It also lets you spot a bad tuber before it goes in the ground: anything soft, weeping or covered in rot goes in the bin, not the row.
• Do not chit in a heated greenhouse or an airing cupboard. Warmth without light produces exactly the weak sprouts you are trying to avoid.
• If tubers arrive already sprouting long and white from the supplier, rub them off and re-chit in the light — the tuber has plenty more eyes.

Common mistakes

• Chitting in a dark cupboard — Darkness produces long, pale, fragile sprouts that break off during planting. The tuber has used stored energy to grow something it then loses.
• Chitting somewhere that freezes — Frost damages the tuber and the sprout. A cool room is right; an uninsulated shed in a cold snap is not.
• Treating chitting as compulsory — It buys earliness rather than yield. If you have not got round to it, plant anyway — an unchitted tuber in warm soil catches up quickly.

Questions people ask