Carrots are an annual cool-season crop, half-hardy to frost and light freezes. They develop quite normally under a variety of temperature conditions, except very warm temperatures. It is often said that frost, or cold weather will make them even sweeter.
Carrots grow quickly at first, sending down a tiny orange root that expands and develops more quickly toward the end of its growing period. As with all root crops, rapid, steady development produces the best results. Keep the row weed free with light shallow cultivation or heavy mulching. The seedlings must have steady moisture to develop well, with less moisture as the roots mature. Too much moisture at the end of maturing will cause the roots to crack. To prevent greening the shoulders, hill up dirt around the greens.
When to Plant
Carrots are hardy, and can be planted as soon as the ground can be worked. For a continual crop, sections of the row can be planted every 2 weeks to late May. For a fall crop, more sowings can be started in late July.
How to Plant
Since carrot seed germinates slowly, it can be mixed with radish or leaf lettuce, which germinate quickly and mark the row. The pulling of radish and leaf lettuce plants will also provide some natural thinning. Carrots do not transplant well, so start them outdoors once the soil is at least 45 degrees F.
Sow seeds evenly in a very shallow furrow, about 1/4 inch deep, and keep seeds moist so they will germinate.
Space rows about 12" apart and when the first leaves emerge, thin to 1" apart; when true leaves emerge, thin to 3" apart.
If you delay final thinning a bit, you can use the removed roots as baby carrots.
How to Harvest
Mature carrots will be ready in about 2 months, although some gardeners find them more succulent when they are pulled earlier than this. A tiny head or crown of orange will appear at the soil line when the carrots are maturing. The diameter of the carrot is a good indication of its maturity level. If the diameter is about what you would expect, the length probably is also. The only way to really know is to pull a few up. Pull only those carrots needed since they remain fresh in the ground for some time. The late summer crop can be harvested in winter if mulched, a light frost is said to sweeten the carrot's flavor. The darkest and greenest tops indicate the largest carrots. Carrots store very well in the fridge when covered in water.