Sowing windows at a glance
| Type | Sow from | Sow until | Notes |
|---|
| Early, under cover | Late February | March | Fleece or cold frame. Mild regions only. |
| Maincrop outdoors | March / April | June | When soil temp exceeds 7°C. |
| Successional sowing | Every 3–4 weeks | Late June | Extends harvest into autumn. |
| Late / winter storage | June | Early July | For autumn harvest and storage. |
These windows apply to most of the UK. In Scotland and northern England, push timings back by 2–3 weeks. In Cornwall, Devon, and southern Ireland, you can start slightly earlier.
The most important factor: soil temperature
The biggest mistake most growers make is sowing too early, into cold soil. Carrot seeds germinate best when the soil is above 7°C — below that, they sit and rot.
The date on the calendar matters less than the soil temperature. A warm late March will produce better germination than a cold April. A soil thermometer is one of the most useful tools an allotment holder can own.
Quick test without a thermometer
If you're seeing weed seedlings emerging in your beds, your soil is likely warm enough for carrot germination. Weeds and carrots have similar temperature requirements.
Successional sowing — the key to a longer harvest
A single carrot sowing gives you a glut in July and nothing in September. Sow in small batches every 3–4 weeks from March through to June, and you'll have carrots ready from late June all the way through to November.
Vercro can turn this into personalised daily tasks based on what you're growing, where you are, and your crop stage — including reminders for when your next successional sowing is due.
Common problems to avoid
Forked roots
Usually caused by fresh manure in the soil or rocky ground. Prepare a deep, stone-free bed and avoid adding manure before sowing.
Poor germination
Almost always caused by cold or dry soil. Water the drill before sowing, cover with fleece if cold, and keep moist until emergence.
Carrot fly
The main pest. Sow under fine mesh or enviromesh, or use resistant varieties like Flyaway. Avoid thinning in the evening when the fly is most active.
Bolting
Caused by cold spells followed by warmth, particularly in early sowings. Use bolt-resistant varieties for very early or very late sowings.
Frequently asked questions
When should I sow carrots in the UK?
Most UK growers sow outdoors from March to July, when soil temperature is above 7°C. Early sowings can be started under cover from late February in milder regions.
Can I sow carrots in February in the UK?
In mild regions like Cornwall and South Wales, yes — under cover or fleece from late February. In colder areas, wait until March when soil temperatures are more reliable.
How do I know when my soil is warm enough for carrots?
Use a soil thermometer (above 7°C is ideal), or look for weed seedlings emerging — a reliable sign the soil is warming enough for carrot germination.
Get personalised carrot sowing reminders
Vercro tracks your crops and tells you exactly when to sow your next carrot batch — based on your location and what's already in the ground.
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