How to Grow Carrots: The Ultimate Beginner’s Guide
Updated: Sep 28
You can grow carrots (Daucus carota) by sowing seed directly into loose, stone-free soil from March to July, 1 cm deep, then thinning the seedlings to 5 to 8 cm apart. Early varieties are ready in 10 to 12 weeks and maincrop carrots in 16 to 20 weeks. The two things that matter most are fine, deep soil and protection from carrot fly.
Carrots are one of the most rewarding root vegetables to grow in Ireland and the UK. Home-grown roots are sweeter and crunchier than shop-bought, and there are dozens of shapes and colours to try. This guide covers choosing a variety, preparing the soil, sowing, thinning, beating carrot fly, and harvesting and storing your crop.
Carrot Quick Facts
Latin name: Daucus carota subsp. sativus
Sow outdoors: mid-March to early July (early varieties under cover from late February)
Sowing depth: 1 cm
Spacing: thin to 5 cm (early) or 8 cm (maincrop); rows 15 to 30 cm apart
Germination: 14 to 21 days, slower in cold soil
Time to harvest: 10 to 12 weeks (early), 16 to 20 weeks (maincrop)
Soil: deep, loose, stone-free, pH 6.0 to 7.0
Position: full sun or light shade
Main pest: carrot fly
Harvest: June to November, with maincrops stored through winter
Step 1: Choose the Right Carrot Variety
Carrots are grouped by when they are sown and how long they take to mature. Choosing the right type for your soil and season makes a big difference.
Early (Nantes and Amsterdam types): fast, sweet and slender. Sow from late February under cover and harvest from June. Examples: Early Nantes, Amsterdam Forcing.
Maincrop: larger roots that store well through winter. Sow April to June. Examples: Autumn King, Chantenay Red Cored.
Short and round types: best for heavy, shallow or stony soil and containers. Examples: Paris Market, Chantenay.
Carrot fly resistant: varieties such as Flyaway and Resistafly suffer less damage, though they are not immune.
Coloured carrots: purple, yellow and white varieties grow the same way and add colour to the plate.
Step 2: Prepare the Soil
Carrots fork, split and twist in stony, compacted or freshly manured soil. Good preparation is the difference between long, straight roots and a tangle of stumps.
Loosen the soil to at least 30 cm deep and remove stones and clods.
Avoid fresh manure, which causes forked roots. Grow carrots where the ground was manured for a previous crop, or dig in well-rotted compost the autumn before.
Rake the surface to a fine, crumbly tilth before sowing.
On heavy clay, use a raised bed, a deep container or a short variety.
Aim for a pH of 6.0 to 7.0. Carrots rarely need extra fertiliser in reasonable soil.
For more on building soil that carrots love, see our guide to composting.
Step 3: Sow Carrot Seeds
Carrots grow best sown directly where they will mature, as they dislike having their roots disturbed. Sow once the soil has warmed to about 7°C, usually from mid-March in Ireland and the UK, and repeat every 3 to 4 weeks until early July for a steady supply. Early varieties can go in under cloches or fleece from late February.
Make a shallow drill 1 cm deep and water the drill before sowing.
Sow thinly, about one seed every centimetre. Mixing the fine seed with dry sand makes this easier.
Cover lightly with soil and firm gently with the back of a rake.
Space rows 15 cm apart for early carrots and up to 30 cm for maincrop.
Keep the surface moist until the seedlings appear in 2 to 3 weeks. A few radish seeds sown in the same row come up fast and mark where the carrots are.
Step 4: Thin, Water and Weed
Thinning: once seedlings are about 5 cm tall, thin them to 5 cm apart for early carrots or 8 cm for maincrop. Do it on a still evening, snip or pinch the unwanted seedlings rather than pulling them, and remove the thinnings. The smell of crushed carrot leaves attracts carrot fly.
Watering: carrots need steady moisture. A sudden soaking after a dry spell causes roots to split, so in dry weather water thoroughly every 10 to 14 days rather than little and often.
Weeding: carrot seedlings are slow and easily smothered, so hand weed regularly for the first few weeks. Once plants are established, a light mulch between rows keeps weeds down and holds moisture.
Feeding: avoid high-nitrogen feeds, which produce lush leaves and hairy, forked roots. Soil prepared with compost the previous year is usually enough.
Step 5: Protect Against Carrot Fly and Other Problems
Carrot fly (Psila rosae) is the most common carrot pest in Ireland and the UK. Its larvae tunnel into the roots, leaving rusty brown channels. The adult flies stay low to the ground and find carrots by smell.
Cover the crop with fine insect mesh or fleece from sowing to harvest. This is the most reliable protection.
Alternatively, surround the bed with a barrier of mesh or fleece at least 60 cm high.
Grow a resistant variety, and sow in early June to miss the first generation of flies.
Plant strongly scented crops such as chives, onions or garlic nearby. The evidence for companion planting is mixed, so use it alongside mesh rather than instead of it.
Other common problems:
Forked or twisted roots: stones, compacted soil or fresh manure.
Split roots: irregular watering.
Green shoulders: roots exposed to light. Draw soil up over the tops.
Missing seedlings: slugs and dry soil. Keep the surface moist and check for slugs after rain.
Step 6: Harvest and Store Carrots
Early carrots are ready 10 to 12 weeks after sowing, once they are about finger-thick. Maincrop carrots take 16 to 20 weeks and are harvested from September to November. Loosen the soil with a fork before lifting, and water the day before if the ground is dry.
Short term: twist off the leaves, leave the soil on and keep them in the fridge for 2 to 4 weeks.
Winter storage: layer unwashed, undamaged roots in boxes of damp sand and keep them in a cool, frost-free shed or garage.
In the ground: in milder areas, maincrops can stay in the soil under a thick straw mulch until Christmas, though slugs and carrot fly larvae may damage some roots.
FAQ: Growing Carrots
When should I sow carrots in Ireland?
Sow carrots outdoors from mid-March to early July, once the soil reaches about 7°C. Early varieties can be sown under cloches or fleece from late February, and sowing every 3 to 4 weeks gives a continuous harvest.
How long do carrots take to grow?
Early carrots take 10 to 12 weeks from sowing to harvest. Maincrop varieties take 16 to 20 weeks and are ready from September to November.
Why are my carrots forked or twisted?
Forked and twisted carrots are usually caused by stones, compacted soil or fresh manure. Loosen the soil to 30 cm, remove stones, and only grow carrots in ground that was manured for a previous crop.
Can you transplant carrot seedlings?
Carrots are best sown directly where they will grow. Transplanting damages the taproot and usually leads to stunted or forked roots.
Can I grow carrots in pots?
Yes. Use a container at least 30 cm deep filled with light, stone-free compost, and choose a short or round variety such as Paris Market or Chantenay. Keep the compost evenly moist.
Looking for a Perennial Alternative to Carrots?
Carrots need resowing every year. If you would like a root crop that comes back on its own, a few perennials fill a similar role in the garden or food forest.
Skirret (Sium sisarum) is the closest perennial match. It produces clusters of sweet, pale roots with a flavour somewhere between carrot and parsnip, was a staple in medieval kitchen gardens, and comes back every year from the same crown. Lift a few roots in autumn and winter and replant a piece of crown to keep it going. It thrives in moist soil, so it suits damp Irish gardens far better than carrots do.
Black salsify (Scorzonera hispanica) is another good option if you prefer to start from seed: sow it in spring like carrots for long, nutty-flavoured roots. For something different, yacon produces crisp, sweet tubers (store the crowns frost-free over winter), and horseradish is a tough, hardy perennial root for the edge of a bed or food forest.
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