Long winters drive many South Dakota gardeners to pore over seed catalogs in anticipation of the warm-season garden. The weather will quickly turn from an intensely cold spring to a very hot, but short, summer. When choosing vegetables, the South Dakota Cooperative Extension recommends looking for varieties described as "heat-tolerant" or "widely adapted."
Asparagus is the first vegetable to be harvested in South Dakota in the spring, according to Joseph R. Thomasson, author of "Growing Vegetables in the Great Plains." Choose hardy varieties such as Jersey King, Viking or Martha Washington. Add more color to your garden with Purple Passion, which produces purple-tinted spears (they will turn green when they are cooked).
Asparagus releases from California such as UC 157 are not hardy enough for South Dakota. Asparagus will not do well will not do well if the soil pH is less than 6.0.
South Dakota gardeners can grow two crops of cabbage during the cool months. Choose an early-maturing variety to plant from March through May. An autumn-maturing variety can be planted from late May to early June. Look for varieties that are tolerant or resistant to head splitting, black rot, tip burn, and Fusarium wilt. Buy hot-water treated seed to avoid blackleg and black rot disease. Good varieties for the Dakotas include Danish Ballhead, Premium Late Dutch and Late Flat Head.
When you select onions to grow in South Dakota, choose day-neutral or long-day types that harvest in 80 to 100 days. If you'd like to grow onions from seed, start them in early March. Hybrid onions will produce more uniform and higher yields than standard varieties. Try growing the Sweet & Early Hybrid or the Kelsae.
The best types of lettuce to grow in South Dakota are leaf, butterhead (Bibb) and Romaine. Crisphead lettuce (like the Iceberg) is not recommended because it needs long, cool summers. Choose a slow-to-bolt or bolt-resistant variety that can stand mid-summer heat. Recommended varieties include Buttercrunch, Oak Leaf, Brown Mignonette and Red Romaine.
If you live in the cooler areas of South Dakota, look for shorter-season watermelon varieties. Most watermelons need 75 to 85 days after planting to reach maturity, but some will take as few as 65 days. Anthracnose-tolerant varieties will spare you trouble with leaf diseases. The Sweet Dakota Rose variety, which has few seeds, was developed by a North Dakota farmer specifically to withstand short seasons. Other good choices are Golden Crown, Sugar Baby and Yellow Doll.