Why are my carrots forked and stunted?

The three causes of misshapen roots — stones, fresh manure and transplanting — and the soil preparation that produces straight carrots.

Difficulty: beginner
Time: 25 min
Read: 3 min

Short answer

A carrot forks when the growing tip hits an obstruction or a pocket of rich material. Stones, fresh manure, lumpy soil and transplanting are the causes. Sow direct into deep, stone-free, unmanured soil, or grow in a container of sieved compost.

Carrots are one of the few crops where the soil does more than the gardener. A carrot that has met a stone at 40mm has already decided its shape, and nothing done afterwards changes it.

What you'll need

Fine sieved compost or stone-free soil
Deep container (optional)
Rake

Step by step

Never transplant carrots.Any disturbance to the taproot forks it. Carrots are sown direct where they are to grow, or into deep modules that go out without any root disturbance at all.
Remove stones from the seedbed.Dig, rake and remove every stone you can from the top 300mm. A stone the size of a fingernail is enough to fork a root.
Do not add fresh manure.A pocket of rich organic matter makes the root branch towards it. Grow carrots on ground manured for a previous crop, not on freshly manured ground.
Break up compaction below.A pan of compacted soil at spade depth stops the root and forces it sideways. Fork the base of the bed through without turning it.
Use a deep container if the soil is stony.A 400mm deep tub, bucket or builder's bag filled with sieved compost and sand produces excellent straight carrots on any soil.
Sow thinly and resist thinning.Thinning releases the smell that attracts carrot fly and disturbs neighbouring roots. Sowing thinly avoids the need almost entirely.
Keep the drill damp until germination.Carrots take two to three weeks and need constant moisture. A dry spell mid-germination gives patchy, uneven rows.
Choose the variety for the soil.Short, stumpy types such as Chantenay, Parisian or Paris Market cope with shallow, heavy or stony ground where long types will always fork.
Water evenly.Drought followed by heavy watering splits carrots lengthwise. Consistency prevents both forking and splitting.
Harvest before they get too large.Overgrown carrots split, go woody and are more attractive to slugs. Pull as you need them.

Tips

Fresh manure and carrots do not mix. Grow them on ground manured the previous year.
A tub of sieved compost gives perfect carrots on the stoniest ground.
Short stumpy varieties are the answer to heavy or shallow soil, not more digging.

Common mistakes

Growing carrots from module-raised transplants — Any check or bend in the taproot at the seedling stage becomes a fork in the mature root. Direct sowing is the only reliable route.
Digging in manure before sowing carrots — The root branches towards pockets of rich material. Carrots do best on ground that was manured for a previous crop.

If it doesn't work

Roots split into two or three legs

Cause: Stone, clod or manure pocket — Fix: Sieve the seedbed or grow in a deep container of fine compost.

Short stubby roots on a long variety

Cause: Compacted layer below — Fix: Fork the base of the bed through, or switch to a stumpy variety.

Roots split lengthwise

Cause: Heavy watering after drought — Fix: Water evenly and mulch.

Tunnels and rusty brown damage in the root

Cause: Carrot fly — Fix: A different problem — barrier fleece or a 600mm high mesh barrier around the bed.

Questions people ask

Why are my carrots forked?

The growing tip hit something — a stone, a clod, a compacted layer, or a pocket of fresh manure. All of them make the root branch, and it happens in the first few weeks.

Can I grow carrots in a container?

Very well. A 400mm deep tub of sieved compost with some sand mixed in gives straight roots on any soil, and it also lifts them above the worst of the carrot fly.

Do I need to thin carrots?

Ideally not. Sow thinly instead — thinning disturbs neighbouring roots and the crushed foliage smell attracts carrot fly from a considerable distance.