Carrots

Growth and cropping pattern

Baby carrots may be ready in four to six weeks, while full-sized roots generally need about three months or longer. The guide gives a broader main harvest expectation of roughly 12–16 weeks after sowing. Lift roots as soon as they are useful rather than waiting for maximum size, because flavour tends to decline as they become over-mature.

Matching roots to the soil

Long carrots grow best in deep, sandy ground. Stones, shallow soil and heavy clay can deflect long roots and produce forks or other distortions, so short or round-rooted types are more suitable in difficult soil. Misshapen carrots remain edible but can be awkward to clean and slice.

Some cultivars offer resistance to carrot fly. For wider reliability, RHS Award of Garden Merit varieties have performed well in trials. Seed is inexpensive, widely available and usually supplied generously in each packet.

No-dig beds and previous crops

In a no-dig system, mulch the surface and sow a short-growing cultivar directly into the mulch. Avoid ground recently occupied by carrots, which may still contain carrot fly eggs; rotation also helps prevent recurring pest pressure.

Do not transplant carrots into the bed. Moving young plants disturbs their taproots and is likely to create forked or distorted crops, so all sowing should be made in the final growing position.

Sowing outdoors

Draw a shallow drill about 1cm (½in) deep and water along its base. Sow the small seeds as thinly as possible, then cover them lightly. Set additional rows 15–30cm (6–12in) apart. Germination can be slow, so keep the area identifiable and remove competing weeds carefully while seedlings emerge.

Protect the bed from slugs and snails and cover it completely with insect-proof mesh to exclude carrot fly. If seedlings are crowded, thin them to a final spacing of 5–7.5cm (2–3in). Remove surplus seedlings carefully and avoid unnecessary handling of the aromatic foliage, which can attract carrot fly.

Sowing in containers

Fill containers with peat-free multi-purpose compost, sow thinly and cover the seed with about 1cm (½in) of compost before watering well. Small, round-rooted cultivars suit most pots. Long-rooted types require deep containers, although they can be lifted young as baby carrots when grown in shallower compost.

Containers are useful for limited spaces and can also provide a clean, stone-free rooting medium. Unlike open ground, however, pots dry quickly and need regular attention to moisture.

Watering

Established carrots resist drought and seldom need irrigation. During a prolonged dry spell, give the crop a thorough soaking about once every two weeks rather than frequent shallow watering. Large swings between dry and wet soil can split the roots. Water container-grown carrots regularly because their compost loses moisture much faster.

Protecting the crop

Carrot fly larvae tunnel into roots, leaving holes that can admit rot and spoil much of a crop. Sowing after mid-May avoids the pest’s first generation, while lifting before late August avoids its second generation. The guide identifies complete coverage with insect-proof mesh as the most effective physical protection against these low-flying adults.

Keep the mesh sealed around all edges and replace it immediately after tending the crop. Combine this barrier with rotation by avoiding recently used carrot ground.

Weeding

Fast-growing weeds can overwhelm fine carrot seedlings. Hoe between rows, but hand weed close to each carrot so the root shoulder is not damaged. Disturb the foliage as little as possible because its scent attracts carrot fly, and close the mesh again as soon as work is finished.

Lifting roots

Pull or lift a few carrots whenever needed rather than clearing the whole row. Main-season crops can remain in use through summer and early autumn, and sound roots may stay in the soil into winter. In heavy ground, loosen them carefully with a fork before pulling so long roots do not snap.

Prompt harvesting is more important than achieving the largest possible root. Regularly check the shoulders at soil level and lift usable carrots while their flavour and texture remain at their best.

Lifting for winter

If the plot becomes waterlogged in winter, lift the remaining carrots rather than leaving them to rot. Handle them gently and transfer sound roots to a crate or box so they remain in useful condition through late autumn and winter. Damaged roots are less suitable for storage and should be used first.