A short row of carrots every three weeks, from March to July

In a typical UK garden, sow carrots outdoors from late March to late July. Sow a short row every three weeks or so and you’ll be pulling carrots from early June until well into winter.

Those dates assume a last frost around 20 April, typical for lowland England and Wales. In Scotland, the north of England and frost pockets, start a couple of weeks later. In the south-west, near the coast and in cities, you can usually start earlier.

Why sow direct

Carrots are sown where they’ll grow. The seedlings make a single taproot early on, and moving them damages it, so transplanted carrots tend to come out short, stunted or forked. Modules and seed trays aren’t worth the effort.

Carrots are hardy to about -10 °C once they’re growing, but the seed needs the soil to have warmed a little to germinate. In a cold March, sowing into cold, wet soil just means the seed sits there. If the soil is still cold, cover the row with a cloche or fleece for a week or two beforehand, or wait until April.

Early and maincrop sowings

Sowing	When	Varieties	Ready
Early	late March to May	Early Nantes, Amsterdam Forcing	from early June
Maincrop	May to June	Autumn King, Flyaway	late summer into autumn
Last sowings	early to late July	quick early types again	October into December

Carrots take 60 to 90 days from sowing to pulling, so a late July sowing still gives you a crop by October. Maincrops can stay in the ground through autumn and be dug as you need them, up to about mid-December, unless the ground is very wet or slugs are a problem.

Soil

Carrots want light, stone-free soil that drains well. Heavy clay and stony ground give you twisted, forked roots. Don’t add fresh manure before sowing: it makes them fork and hairy. A bed that was manured for last year’s crop is ideal.

On heavy soil, grow short or round varieties, or use a raised bed or deep container filled with compost.

How to sow

1. Rake the soil to a fine, crumbly finish and take out any stones.
2. Make a drill about 1 cm deep. Leave 20 cm between rows.
3. Water the drill first if the soil is dry, then sow the seed thinly along it.
4. Cover lightly with soil and firm gently with the back of the rake.

Carrot seed is tiny and easy to sow too thickly. Mixing it with a pinch of dry sand helps spread it out.

Thinning

When the seedlings are a few centimetres tall, thin them to about 5 cm apart. Do it in the evening on a still day, water the row afterwards to settle the soil, and take the thinnings away rather than leaving them on the bed. Crushed carrot leaves give off a smell that draws carrot fly from some distance.

The more thinly you sow, the less thinning you have to do, and the less you attract the fly.

Carrot fly

The carrot fly’s maggots tunnel into the roots, leaving rusty brown channels. It’s the main pest of carrots in the UK. The adults fly low, close to the ground, which is the key to stopping them.

• Cover the crop with fine insect mesh from sowing, with the edges tucked in or weighted down.
• Put up a barrier of mesh or clear polythene about 60 cm high around the bed. The flies mostly stay below it.
• Sow thinly and thin carefully, as above.
• Grow a resistant variety such as Flyaway or Resistafly.
• Time your sowing. Sowings made in early June often miss the first generation of flies, which lay their eggs in late spring.

Onions, leeks and chives are often grown alongside carrots in the hope that their smell hides the crop. Mesh is far more dependable.

Common problems

• Patchy germination. Usually dry soil or seed sown too deep. Keep the drill moist until the seedlings are up.
• Split roots. Heavy watering or a downpour after a long dry spell. Water regularly in dry weather rather than in a sudden flood.
• Green shoulders. The top of the root has been in the light. Draw a little soil over any that show.

If you want to keep track of a row every three weeks without losing count, VegLog puts each sowing on your weekly to-do list.