Radish Growth vs. Collard Growth

Early Growth

• Both radishes and collards are cool-season, annual crops that can be sown in early spring or fall. Radish seeds can be planted outdoors three to six weeks before the last frost; Collards are best planted three weeks before the last frost. Both can be planted again in midsummer for a fall crop. Radish seeds germinate in three to four days at 55 to 85 degrees Fahrenheit and mature within four weeks, making them one of the fastest growing vegetables. Collards take more time. Their seeds germinate in about seven days when soil temperatures range from 45 to 85 degrees Fahrenheit. From planting to harvest, collards need 60 to 75 days to mature, depending on the variety and growing conditions.

Height

• Radishes and collards both thrive in cool conditions, but there the similarities end. Radishes are grown for their pungent, crisp roots while collards are grown for their leaves. Radishes, with their upright, vertical growth, take almost no room in a garden. Space them 2 inches apart in rows 12 inches apart, or tuck them among other cool-season vegetables. Collards start out small but quickly mature to large plants that grow 18 inches tall. When they stand 6 inches tall, remove some of the collard plants so the remaining plants are 12 inches apart

Use

• In addition to differences in size and harvest time, collards and radishes are used differently. The roots are the edible part of the radish, and once you pull them up, the harvest is over until more grow to replace them. Collards produce large, leafy stalks. Remove the outer leaves first, and allow the inner leaves to continue growing for a repeat harvest. Radishes typically are used fresh in salads, although some people pickle them. Collards generally are steamed or roasted and can be frozen for winter use.

Growing Conditions

• In spring, radishes and collards need full-sun exposure to promote quick, vigorous growth. During summer, radishes dwindle and become woody, but collards can take a bit more heat. No matter the season, both plants grow best in fertile, loam soil and consistently moist conditions. Water their soil as often as needed to keep the soil moist 1 inch beneath the surface. Neither radishes nor collards suffer from serious pest or disease problems. Rotate the crops, and install floating row covers after planting to thwart flea beetles and root maggots.