How to Grow Carrots and Radishes Together

Plant carrot and radish seeds just before the last spring frost. Both crops demonstrate good frost hardiness and do best with starts at 50 to 55 degrees Fahrenheit. Carrot and radish seeds fail in hot or dry soil.

Plant carrots and radishes in areas with quick drainage and four to six hours of full sun every day. Root crops drown and rot in standing water. Plant the seeds among taller crops for space efficiency.

Dig into the top 8 to 10 inches of soil. Remove rocks, weeds and old roots. Compacted or rocky soil stunts and retards carrot and radish growth. Turn 4 to 5 inches of bagged garden loam, sand, or organic compost into the tilled soil for a loose, crumbly foundation. Carrots and radishes need a loose consistency and good moisture for growth. Add 5-10-10 fertilizer per manufacturer directions.

Plant radish seeds at every inch in the row, with 12 to 24 inches between rows. Plant carrot seeds every 1/4 inch in the row, with 12 to 24 inches between rows. Plant every 10 days until mid spring for a continued harvest.

Water with 2 inches of water every week to keep soil moist. Dry conditions stunt carrot and radish growth. Lay 2 inches of organic mulch over the soil around the plantings to maintain soil moisture and protect your harvest.

Thin carrot seedlings to every 2 inches in the row after three to four weeks, to give them more room to grow.

Harvest radishes when they reach 1 inch in size, and carrots starting when they reach finger size. Leave carrots in the ground indefinitely into the summer, and harvest at need.