Growing Carrots in Scotland: The Complete Guide

Daucus carota

Everything you need to grow carrots in Scotland, including the honest answer about onions and carrot fly. We have done the research so you don't have to.

Carrots are undemanding once they are up: they barely need watering, they rarely need feeding, and they will sit in the ground through winter waiting for you. Two things decide whether you get a good crop, and neither is about care. One is your soil, which determines whether the roots grow straight or fork. The other is carrot fly, which is the reason most people give up on them.

Why Scotland may be kinder to carrots than you expect

The standard advice for carrot fly, ours included further down this page, is to cover the whole crop with mesh all season.

Before you buy mesh for the whole plot, though, it is worth knowing that carrot fly is patchy across Scotland. Some areas carry damaging populations; others are still effectively fly-free, and precautions are not always needed.

Ask at a nearby allotment or a neighbour who grows vegetables. Finding out whether the fly is actually present where you are is ten minutes of conversation that can save you a season of unnecessary work. Where it is established, sow late with a quick-bulking variety and cover the crop.

Varieties

Every variety here carries the RHS Award of Garden Merit, a UK-wide award rather than a Scottish one. The pick below is our judgement, reasoning shown.

Also worth considering

Do not overlook the shape question when choosing. On stony or heavy ground, a short round-rooted variety will give you a better crop than a long-rooted one struggling through obstructions, whatever the awards say.

Soil and site

More carrot disappointment comes from the ground than from anything you do afterwards. Roots need to drive straight down, and anything in the way makes them fork, twist or split around it. Stones, clods and compacted ground all do it, and so does freshly manured soil.

Prepare the bed by weeding thoroughly, forking it over to break up lumps, picking out stones, and raking to a fine crumbly texture. Carrots want deep, light, sandy or sandy-loam soil, which is what produces straight roots and clean skins.

If your ground is stony, shallow or heavy clay, you have a choice that is worth making deliberately: either invest real effort in preparing a bed, or grow short, round-rooted varieties instead, which are far less prone to becoming misshapen. On a lot of Scottish ground the second option is the sane one, and it is a genuine solution rather than a compromise.

Sowing

Sow early varieties from February to March under cover, and main-season varieties from April to July outdoors. Sow directly where the plants are to grow, because carrots resent root disturbance and do not transplant.

Sow about 1cm (½in) deep, in rows 15 to 30cm apart. Sow in small batches every three or four weeks rather than everything at once, and you get a steady supply instead of a glut.

Be patient after sowing. Carrot seed germinates slowly, and it is easy to conclude nothing has happened and dig the row over.

Thinning

Thin seedlings to 5cm to 7.5cm apart. Overcrowded carrots compete and come out distorted, so this is not an optional tidy-up.

Thin in the evening, and take the thinnings away with you. Bruised carrot foliage releases the smell that draws carrot fly in from a distance, and a row of crushed seedlings left lying on the soil is an advertisement. Water the row afterwards to settle the disturbed soil back down.

Watering and weeding

Carrots are drought-resistant and seldom need watering once established. What they do want is consistency: a long dry spell followed by heavy rain or watering makes roots split. Containers are the exception and dry out quickly, so they need regular attention.

Hoe between the rows and hand-weed close to the plants. Try not to brush the foliage as you go, for the same reason as thinning: the smell of bruised carrot leaves attracts the fly.

Carrot fly, and what actually works

Carrot fly larvae tunnel into the roots, leaving rusty brown channels that make them inedible. You will not see the damage until you lift the crop, which is what makes it so demoralising.

The most effective prevention is covering the crop entirely with insect-proof mesh. These are low-flying insects, so a barrier works well as long as it is complete, with the edges sealed to the ground rather than merely draped over.

There are two timing levers that work alongside it:

• Sow after mid-May and you miss the first generation.
• Harvest before late August and you miss the second.

Also rotate: do not sow carrots where carrots grew last year.

Harvesting and storing

Carrots are ready about 12 to 16 weeks after sowing, and baby carrots much sooner. Lift them when they are big enough to use; younger roots taste better than older ones, so there is no advantage in waiting for size.

Lift carefully with a fork rather than pulling, particularly on heavy soil, or you will snap the roots and leave the ends behind.

For winter, the simplest storage is to leave them where they are: cut off the leaves and cover the row with straw or cardboard against frost, then lift as you need them. The exception matters in Scotland. If the ground gets waterlogged, lift and store them instead, somewhere cool and dry, because roots sitting in saturated winter soil will rot.

Common problems

• Carrot fly is the main one, covered above. Rusty brown tunnels through the root, invisible until you lift it.
• Forked or twisted roots come from stones, lumps, compaction or fresh manure. A preparation problem, not a growing one.
• Split roots follow a dry spell broken by heavy rain. More about consistency than quantity of water.
• Green tops on the shoulders are simply sunlight reaching the crown. Harmless, and easily prevented by drawing a little soil over the row.
• Nothing coming up is usually impatience. Carrot seed is genuinely slow, so give it longer than feels reasonable before resowing.

Common questions

Sources