Carrots are a staple of British allotments — easy to grow, nutritious, and rewarding to harvest. With the right soil preparation and timing, you can enjoy crisp, sweet roots from early summer through to autumn. This guide explains everything you need to know about growing carrots successfully, from seed to storage.
Quick Facts
| Metric | Details |
|---|---|
| When to Sow | March to June |
| Germination Time | 10–20 days |
| Time to Harvest | 12–16 weeks |
| Ideal Soil | Light, sandy, well-drained soil |
| Position | Full sun |
| Spacing | 10cm apart, 30cm between rows |
Preparing the Soil
Carrots thrive in light, stone-free soil. Heavy or clay soils can cause roots to fork or split.
Before sowing, dig the bed thoroughly and remove stones and debris. Avoid adding fresh manure — it encourages leafy growth and misshapen roots.
If your soil is compacted, create a raised bed or use deep containers filled with free-draining compost and sand.
Sowing the Seeds
Sow carrot seeds thinly in shallow drills about 1cm deep, spacing rows roughly 30cm apart. Water the soil lightly before sowing.
You can stagger sowings every three weeks from March through June to enjoy a continuous harvest. Cover with fine soil and keep moist until germination.
Watering and Feeding
Carrots prefer consistent moisture but not waterlogging.
Water deeply once or twice a week during dry spells. Avoid overwatering once roots begin forming, as this can cause splitting.
They don’t require much feeding — too much nitrogen encourages excessive foliage rather than roots.
Thinning and Maintenance
When seedlings reach 2–3cm tall, thin them to 10cm apart to allow room for growth.
To prevent carrot fly, thin plants on a calm evening (the scent attracts the pest) and immediately cover with fine mesh or fleece.
Keep beds weed-free by hand-weeding carefully around the roots.
Harvesting and Storage
Harvest carrots when they reach your preferred size — baby carrots are tender, while mature ones have deeper flavour.
Loosen the soil gently with a fork before pulling.
Cut off the foliage and store roots in boxes of sand or dry compost in a cool shed over winter.
Common Problems and Solutions
| Problem | Cause | Solution |
|---|---|---|
| Carrot fly | Attracted to carrot scent during thinning | Use mesh covers or companion planting (onions, chives) |
| Forked roots | Stony or recently manured soil | Use fine soil, avoid fresh manure |
| Poor germination | Soil too cold or dry | Wait until soil warms in spring and keep moist |
Companion Planting Tips
Carrots grow particularly well alongside onions, leeks, and chives — their scent helps deter carrot fly.
Avoid planting near dill or parsnips, which can attract similar pests.
Using the Allotment Planner Tool
You can visualise your carrot beds using the Allotment Planner tool.
Simply drag and drop carrot rows onto your digital plot to check spacing, rotation, and companion placement — perfect for planning a productive and well-balanced allotment.
FAQs
When should I plant carrots?
From March onwards once the soil temperature is above 7°C. Early sowings benefit from a fleece cover.
How long do carrots take to grow?
Most varieties mature in 12–16 weeks, depending on the variety and weather.
Can I grow carrots in containers?
Yes — choose a deep pot (at least 25cm) and a fine, sandy compost mix.
How often should I water carrots?
Water deeply once or twice a week during dry periods rather than frequent shallow watering.
What’s the best variety for beginners?
‘Autumn King’ and ‘Nantes 2’ are reliable, flavoursome choices for most allotments.