QUESTION: Why are my carrots so small? Am I doing something wrong when planting them? -Joseph H.
ANSWER: Maybe they are baby carrots? Ha ha! Just kidding there. Most often, when carrots turn out small or underdeveloped it is because the soil they are growing in is not loose enough for them. You can loosen heavy soil to solve this problem by amending it with sand or broken down leaves. Carrots especially tend to struggle in clay soil. If you are gardening in an area with clay soil, you may find our article “Amending Clay Soils” helpful.
Your carrots can also turn out too small if the weather is too hot when they are planted. The ideal soil temperature for carrot seeds to germinate is between 55 and 75 degrees.
Carrots that are overcrowded also tend to turn out small, so when you are growing carrots, you must thin them out earlier than many other crops. Just a week after sowing carrot seeds, thin them out to leave an inch or two between seedlings. Then a few weeks later, thin your carrots out again to leave three or four inches between plants.
If your carrot plants don’t get enough water, your carrots can also fail to reach the usual size.
If all these causes have been ruled out, you may be dealing with root knot nematodes, which can be detected with a soil test from your local exchange. You can handle root knot nematodes by solarizing your soil (heating it up to kill the nematodes) or moving the carrots to a different part of the garden next season.