How to Grow Carrots
Carrots have a reputation for being a bit fiddly, but most of the problems come down to the same few things: difficult soil, letting the seedbed dry out, sowing too thickly and carrot fly. Get those under control and carrots are actually a lovely crop to grow.
And don’t get hung up on producing perfectly straight supermarket carrots. Some will fork, some will come out looking downright peculiar, and every now and then you’ll pull one that’s absolutely perfect. They’ll all taste like carrots.
When to Sow
You’ll often see March given as the starting point for sowing carrots, and in a mild spring that’s perfectly possible. But I tend to let the soil tell me when it’s ready rather than relying too heavily on the calendar.
If the ground is cold, sticky and clinging to your boots, carrot seed isn’t going to thank you for putting it in. Wait until the soil starts to warm and becomes easier to work. An April sowing into decent conditions will often catch up with seed sown several weeks earlier into cold ground.
Once you start, sow a short row every three or four weeks. It’s much more useful than sowing the entire packet and having everything ready together.
Early varieties are ideal for pulling young through summer. Sow maincrop varieties from April into June for larger autumn carrots, and I’ll often make one last sowing of a quick variety in July. They won’t necessarily become huge, but they make cracking little carrots later in the season.
Preparing the Ground
Good carrots start with what’s underneath the soil, so this is one job I wouldn’t rush.
Push a fork into the ground and loosen it to at least a spade’s depth, taking out any decent-sized stones as you go. You’re trying to give the root an easy run downwards. If it meets a stone or a hard lump, it simply grows around it, which is how you end up pulling carrots with two legs — or occasionally something far more entertaining.
Rake the surface down reasonably fine before sowing. It doesn’t need to be perfect, but those tiny seeds establish much better without great clods of soil sitting on top of them.
Avoid freshly manured ground. Carrots really don’t need it, and overly rich soil often gives you forked roots and a great show of foliage.
On heavy clay, I’d choose shorter varieties rather than battling to grow enormous long roots. Raised beds and deep containers are good alternatives too. Grow the carrot that suits your soil and life becomes much easier.
When the soil doesn't product good carrots then try growing them in pots.
How to Sow
Carrot seed is tiny, so the aim is to sow thinly — although I’ve yet to meet many gardeners who manage a perfectly spaced row.
Make a shallow drill about 1cm deep. If the soil is dry, water along the drill first and give it a few minutes to soak in. I much prefer this to sowing and then giving the row a soaking, which can wash the little seeds together.
Pour a few seeds into your palm, take a pinch between finger and thumb and work slowly along the row. Try for a seed every 2–3cm, but don’t worry about getting it exact. You’re growing dinner, not entering a seed-sowing competition.
Cover with a thin layer of fine soil and gently firm it with the back of your hand.
Now keep an eye on the surface. Carrots can take a couple of weeks, sometimes longer, to appear, and the top centimetre of soil can dry remarkably quickly on a sunny or windy day. A gentle watering with a fine rose is all that’s needed.
I like rows about 20–30cm apart because there’s enough room to weed between them without trampling everything.
One last thing: don’t start carrots in trays with the idea of planting them out later. Sow them where they’re staying. Disturb that young taproot and you’re asking for some very oddly shaped carrots.
Thinning and Growing On
This is where sowing thinly pays you back. If the seedlings are already nicely spaced, leave them alone. The less you disturb a row of carrots, the better.
Where they’ve come up in clumps, thin them once they’re large enough to handle. Around 3–5cm apart is fine for carrots you’ll pull young; give them nearer 5–8cm if you’re after bigger roots.
It can feel wasteful pulling healthy seedlings out, but six carrots trying to grow in the space meant for two won’t give you six decent carrots. They’ll mostly give you six pencils.
I like to thin after watering or when the ground is naturally damp. The unwanted seedlings come away more easily and there’s less disturbance to their neighbours. Don’t try moving the thinning's elsewhere — once that little root has been disturbed, a straight carrot is unlikely.
Take the thinning's away afterwards. Crushed carrot foliage has a strong smell and can help carrot fly find your crop.
From then on, keep weeds down while the carrots are young. Once the foliage fills out, there’s surprisingly little else they need from you.
Watering and Feeding
Carrots don’t want mollycoddling. Once established in the ground, they can cope with a bit of dry weather and I’d much rather give them one decent watering than wander past every evening with a watering can giving them a splash.
The important time for moisture is during germination. Those tiny seeds sit close to the surface, so don’t let the seedbed dry out completely while you’re waiting for them to appear.
Later on, water thoroughly during prolonged dry spells. Try to keep things reasonably even because very dry ground followed by a sudden drenching can cause roots to split.
Carrots in pots are different. Containers can dry out surprisingly quickly, so check them regularly in warm weather.
Feeding is something I’m cautious about with carrots. If the soil is reasonably good, they usually need nothing. Too much nitrogen produces fabulous ferny foliage and leaves you wondering where the actual carrots went. On poor ground, use a little balanced feed, but go easy.
Harvesting
There’s no great mystery to knowing when a carrot is ready. Brush the soil away from the shoulder and have a look. If it seems a useful size, pull one and see.
In fact, I’d encourage you to start harvesting before they reach their maximum size. Young carrots are sweet and tender, and pulling a few early also gives the remaining roots a little extra room.
If your soil is light, carrots often pull easily. Hold the foliage right down near the crown and lift steadily. If they resist, stop pulling. That’s the moment when the leaves usually snap off and leave the carrot smugly underground. Push a fork into the soil alongside the row, loosen it slightly and try again.
Early carrots are best pulled as you need them. Maincrop varieties can sit happily in the ground into autumn and often taste even better after some cool weather.
If your ground becomes waterlogged in winter or you have trouble with slugs, though, I’d lift the main crop rather than leaving my luck underground.
Common Problems
Carrot fly is the big one. You often don’t realise you’ve got it until harvest, when you pull what looks like a perfectly respectable carrot and discover rusty brown tunnels running through the root.
Fine insect mesh is the method I trust most. Get the crop covered early, keep the mesh over it and make sure the edges are properly secured. Carrot fly only needs one way in, and an inviting gap underneath rather defeats the object.
You’ll sometimes hear that carrot fly can only fly very close to the ground, so simply raising the crop will stop it. I wouldn’t rely on that. If carrot fly is a regular problem in your garden, use a proper physical barrier.
Sowing thinly helps too because you won’t need to disturb the plants as much. When you do thin, remove the seedlings straight away. That lovely fresh-carrot smell is exactly what you don’t want advertising around the garden.
Forked carrots usually come down to the soil. Stones, compacted ground, fresh manure or damage to the young root can all cause them. Unless the damage is severe, they’re still perfectly good to eat.
Splitting is generally a watering issue — typically dry soil followed by lots of moisture.
Patchy germination is perhaps the most frustrating problem of all. Nine times out of ten, the surface has dried while the seed was germinating. Keep the row damp and, above all, be patient. I’ve nearly resown apparently empty rows before, only for the original carrots to appear a few days later.
And remember, home-grown carrots don’t need to be straight. If you pull one shaped like a pair of trousers, take the photo, have a laugh and eat it anyway.
