How Much Sunlight Is Needed to Grow a Carrot?

While the edible orange root of a carrot plant (Daucus carota) stretches into the dark soil as it grows, the plant itself requires sunlight to fuel that growth and create sugars to form a sweet carrot. Sow carrot seed in your home garden as soon as the soil can be worked in the spring.

Carrots are most successful in sunny sites, though they can tolerate light shade, according to Cornell University's website, while University of Arkansas Extension bumps that up to partial shade. Full sun is defined at unimpeded sunlight all day or for at least eight hours. Light shade means the area has two to three hours of shade during the time the sun is at its most intense -- from 10 a.m. to 6 p.m. -- or a pattern of dappled or shifting light shade all day. Partial shade, on the other hand, allows for up to five hours without direct sun from 10 a.m. to 6 p.m., or an equal pattern of shifting sun and shade all day. The hotter your climate is in general, the more shade your carrots will tolerate.

Aside from the proper amount of sun, soil is the most important consideration in growing carrots. Carrots prefer a loose, sandy soil for the longest, most well-formed roots. Gardeners with clay soil should work in plenty of compost to improve the soil's texture and drainage, as the root vegetables are prone to rot when the soil stays moist. Cultivars that produce shorter, more rounded roots are available for gardeners who want to grow carrots in clay.

Tiny carrots seed can be sown as soon as soil can be worked in the early spring or in the late summer for a crop that overwinters, depending on the cultivar you plant. Carrot seed is slow to germinate and radish seeds, which are larger and quick to grow, are often planted with carrots to mark the row and break up the soil for the carrots. The radishes will be harvested long before the carrots grow large enough to be affected by the radishes. Most carrots take 65 to 70 days to reach harvest, though some, like Baby Sweets, are mature in as little as 49 days and overwintering varieties, like Healthmaster, aren't ready for 130 to 150 days after planting.

Despite the carrot plant's need for sun, its rays can damage the developing root. As the root develops, its rounded top tends to emerge from the soil. The exposed portion of the carrot can turn dark green and bitter tasting. A little mid-season maintenance work can prevent this "sunburning." As carrots emerge, recover your carrot row with just enough soil to protect the exposed tops.