Is it possible to put them outside, under glass, in a light place? Bring them in at night if it looks like a frost.

They need a lot of light, but a very cool temperature!
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It sounds that you are on heavy soil, which is difficult to grow carrots on, if not impossible, because of the problems you are finding. When it rains the soil goes like concrete.

On our heavy soil we have incorporated coarse sand to make it more friable. The sand particles help to keep the clay particles apart. You need a lot of coarse sand to have any effect. You need so much that it is not really practical.

As you have discovered, adding a lot of organic matter does not solve the problem, because you need to add so much.

Carrots have always been grown on sandy soils, or sandy-loams.

One solution is growing them in a container - which you can fill with the perfect growing medium!

Keep in touch and let us know how you get on with next years carrots

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