At this time of year, many gardeners are digging up buried treasure. We're not talking about pieces of eight, but those delicious root vegetables that have been fattening up underground and are now ready to unearth for some delicious eating. While the harvest of carrots, beets and the like may have begun earlier in the season, fall is a time when many of the root vegetables produce their most bountiful crops. And, given the right conditions, many of these tasty roots can be stored for enjoyment later in the fall, sometimes even into the winter months.
Root crops are those vegetables that develop their primary eating part below the surface of the soil. While they all need fairly similar growing conditions, botanically speaking they are a mixed bag, representing several different plant families.
Carrots One of the most familiar of the root crops, carrots are in the Apiaceae or carrot family. They are nutritional powerhouses, full of the beta-carotene that our bodies covert to Vitamin A, a well as Vitamins K and C. Carrots are available in a range of sizes and shapes, from small, round ball types to long, slender, pointed Imperator varieties.
Beets These members of the Chenopodiaceae or goosefoot family not only deliver delicious roots but edible and nutritious greens as well. And while we may describe things as "red as a beet," these veggies are also available with golden colored flesh.
Turnips, rutabagas, and radishes All these cabbage family members provide us with tasty roots. Fast-maturing radishes and turnips are great choices for both spring and fall planting, and like beets, turnips also can be grown for their edible leaves. Earthy rutabagas take longer to mature and store well.
Here are just some of our root crops to try in your garden:
'Ruby Queen' Beet - This popular canning variety has a fine, buttery texture and uniform, dark-red interior.
'Scarlet Nantes' Carrot (68 days) - These 6-inch long, blunt-tipped carrots have a sweet taste and uniform orange interior.
'Imperator 58' Carrot (77 days) -Long, slightly tapered roots have a medium orange color.
'American Purple Top' Rutabaga (100 days) - Purple-topped, globe-shaped roots have creamy yellow flesh with a fine flavor.
'Seven Top' Turnip (40-50 days) - This variety is grown only for its dark green leaves, which are harvested when they are young and tender.
'Chinese White Winter' Radish (60 days) - With square tops and blunt tips, these 8-inch long radishes have creamy white skins and crisp, solid, snowy flesh.
'Sparkler' Radish (25 days) - Almost round, with bright scarlet skin and crisp, tender white flesh, this quick maturing radish is popular with home gardeners.
The large, tender roots of these crops that we harvest and enjoy are something of a luxury for the plant itself. If the plant is stressed by poor growing conditions, it won't be able to spare the energy needed to store excess carbohydrates in the form of edible roots. A struggling plant may survive, but its root will be skimpy and tough. So it's important to give root crops the conditions they need to keep growing rapidly and evenly if we want a good harvest.
Good soil equals good roots. Make sure the soil where your root crops grow is loose and rock-free. If you have heavy clay soil, add compost or other organic matter to lighten it or consider making raised beds. Short, rounded varieties of carrots and radishes will be more successful in compacted or stony soil than longer varieties.
Watch out for excess nitrogen. While root crops need fertile soil, excess nitrogen can be too much of a good thing. Carrots grown in soil too high in nitrogen will develop lots of little feeder roots along the main root, making them unappealingly hairy. But do make sure your soil is well supplied with phosphorus and potassium.
Don't neglect thinning. It's hard to sow tiny carrot seeds thinly, so the carrot patch just about always needs thinning so plants have adequate room to develop. When carrot seedlings are about 2 inches tall, use a small pair of scissors to cut down extra seedlings at the soil line, leaving 3-4 inches between the remaining plants. Simply yanking out the discards may damage the keepers. Beet "seeds" are actually fruit capsules with multiple seeds, so beets always need thinning as well. Use the same technique described for carrots, leaving 3-6 inches between seedlings, depending on the size at which you plan to harvest the roots. Thin turnips to 4 inches, and give heftier rutabagas 8 inches between plants.
Make sure root crops have abundant and consistent moisture. Regular watering will produce the sweetest and most tender roots. Mulch will help to retain soil moisture. It will also help keep down weeds that compete with your crops for water and nutrients.
Plant spring and fall crops. Root crops grow best when the growing weather is on the cool side. In most parts of the country you can plant in spring for an early harvest, then again later in the summer, about 8 weeks before the first fall frost date, for a late harvest. The exception is rutabagas, which are usually sown about three to four month before the fall frost date for fall harvest. With quick-maturing radishes and in mild-winter areas, you may be able to make repeat sowings of root crops into mid to late fall.
Q: I planted beets this past spring. Some of the plants just produced leaves on top, but others sent up flower stalks and the roots were tough and bitter. Why did this happen?
A: Your beets bolted, which is the term we use when plants from which we harvest leaves or flower buds begin to flower and set seed, usually with a loss in eating quality. Daylength and temperature are triggers for bolting. Beets and carrots are biennials, meaning that they grow vegetatively the first year, then flower, set seed, and die in their second season. Of course, we usually harvest them the first year, so they never get to that second season. But if beet or carrot seedlings are exposed first to cool temperatures (below 45 degrees), then to the long days of June, they "think" that they have been through a winter and that it's time to begin flowering. To avoid bolting, wait to plant these root crops until just a few weeks before your last frost date in spring.
Article published on October 24, 2011.