Carrots need space to develop fully so, once germinated, go over your rows of carrots and pick out the weakest-looking vegetable seedlings to leave a 2-4cm space around remaining seedlings. If you’re very careful in extracting the seedling from the row, you could try transplanting it into a new row and watering it in well to help it establish itself again. Repeat the thinning in three to four weeks. Carrot root fly is always a threat to your carrots, and never more so at thinning out time, so be ready to cover them with horticultural fleece to prevent the fly from laying eggs on your crop.
You Will Need
Water carrot seedlings well before thinning. This will allow you to pull them out without breaking the roots, the smell of which attracts carrot root fly. Simply grip the seedling to be removed between thumb and forefinger and pull. Aim to leave seedlings at 2cm – 4cm spacings. Cover with horticultural fleece to ward off carrot root fly.
After three to four weeks, repeat the thinning procedure to leave the seedling at a spacing of 4cm – 8cm apart. This second thinning usually produces tiny carrots that can be trimmed for use in salads or as a garnish.
If you don’t mind small carrots, make just one thinning to leave seedlings 4cm apart.