BECAUSE there’s so much that can go wrong with maincrop carrots and because they are not usually expensive in the shops, I know a lot of gardeners don’t bother growing them.

They’re definitely worth a try, though — the superior taste and crunch of a home-grown carrot is really something special. So, if you’ve been having trouble growing big, juicy carrots, here are some of the things you might have been doing wrong.

First of all, don’t sow them yet. The seed packets suggest that they can be sown in spring, which they no doubt can under ideal conditions, but I’ve learned over the years not to start mine until May or June. Carrots germinate very poorly in cold, damp soil.

The seedlings also suffer if the soil doesn’t yet have a fine enough tilth. If the surface of the ground is hard and heavy rather than light and open, the crop may germinate but then struggle to push through into the light. Too much overhead watering, from a can or hose, can also cause a crust to form on the bed. If you sow a row that comes up only in patches, that may well be what’s happened.

On the other hand, a row that doesn’t appear at all — or else comes up and then vanishes — has probably been eaten by slugs or snails. A soil surface that is warm, fairly dry, finely textured and free of weeds will at least inhibit mollusc attacks.

Carrot seed has neither the shortest nor the longest shelf life. Experiments suggest it’ll remain viable in its packet for around three years. If possible, though, I would recommend buying a fresh packet every year or at least every other year.

Carrot root fly is the most troublesome carrot pest in this country. When you dig up your carrots at the end of the season and find they are full of tunnels, the larvae of the root fly is almost certainly responsible.

There’s no cure, but all sorts of preventatives are commonly suggested. I’ve tried most of them at one time or another and I’m convinced that the only one which will definitely work is covering the entire carrot bed, from sowing until harvest, with a tunnel made of horticultural fleece. If the adult fly is physically unable to get at the carrots to lay her eggs, then there can’t possibly be any maggots to tunnel into the roots.

Except that there can, if overwintering pupae, already in the soil from last year’s generation, emerge within your tunnel. The way to avoid that is to practise crop rotation if you can. Make sure you don’t grow your carrots in the same part of the plot where you put them last year.

“Forked” carrots — those which, at harvest, have two or more lengths of root instead of one long, straight one — are usually caused by stones in the soil. There’s nothing wrong with the carrots. They look a bit comical but taste just the same.

You can support Mat Coward’s new book, Eat Your Front Garden, through its crowd-funding campaign at mstar.link/mc-front-garden