Chitting Seed Potatoes

Why chit at all

A chitted tuber goes into the soil already growing, so it emerges faster and matures sooner — the point being an earlier crop, which matters most for first and second early varieties grown for the quickest new potatoes.

It also works as quality control: six weeks on a windowsill reveals any tubers that are soft, rotting, or refusing to sprout before you've wasted garden space on them.

For maincrop varieties with a long growing season ahead of them, the head start washes out — the RHS sees no real advantage there — so chit your earlies and plant maincrops straight from the bag if you prefer.

The method

Examine each seed potato and find the end with the most eyes (the 'rose' end). Stand the tubers with the eyes uppermost in egg boxes or seed trays — the classic egg-box trick exists purely to hold them upright.

Put the boxes somewhere bright, cool, and frost-free: an unheated spare room or bright porch is ideal. Light is the key detail — in darkness potatoes throw the long, pale, fragile shoots you see in a forgotten kitchen bag, while in light they make the short, stubby, dark sprouts you want.

Wait a few weeks. Shoots are ready when they're roughly 3–5cm (about 1–2in) long, sturdy, and green-purple. Handle the tubers gently at planting so the sprouts don't snap off — plant them sprouts-up.

Timing it to your planting date

Count backwards: chitting takes roughly four to six weeks, so start about six weeks before you intend to plant. RHS guidance for the UK: begin in late January in milder areas, up to early March in colder ones, for planting from around late March as soil warms.

Outside the UK the same arithmetic applies to your local potato-planting window — start chitting about six weeks before your area's planting date, keeping the tubers frost-free throughout.

If planting is delayed, chitted potatoes hold happily in their cool bright spot — the sprouts just keep slowly thickening until the soil is ready.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• RHS — How to grow potatoes — Chitting lets seed potatoes sprout short shoots before planting for a head start; stand tubers in egg boxes or seed trays with the eyes uppermost in a bright, frost-free location until sprouts are about 5cm (2in) long within six weeks; start late January in milder areas to early March in colder spots for first and second earlies; worthwhile for early varieties, no real advantage for maincrops.
• RHS — Chit early potatoes (Grow It activity) — Arrange seed potatoes with eyes uppermost in egg boxes or seed trays in light in a cool but frost-free room; shoots appear after a few weeks and tubers can be left until the soil is warm enough for planting.

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