How do I harvest and store sweet potatoes? 

Harvest sweet potatoes immediately before or after a vine-killing frost. When harvesting sweet potatoes, dig carefully to avoid cutting or bruising the roots. After harvest, cure the sweet potatoes for 1 week at 80 to 85 F and relative humidity of 90 to 95 percent.  Curing promotes healing of minor cuts and bruises, prolonging the storage life of the sweet potatoes. Curing also improves the flavor of sweet potatoes as starches are converted to sugars during the curing process. After curing, store sweet potatoes at 55 to 60 F and relative humidity of 85 to 90 percent. Storage temperatures above 60 F may stimulate sprouting.  Sweet potatoes may develop an off-flavor and the flesh may become discolored when stored at temperatures below 55 F. If properly cured and stored, sweet potatoes can be stored for four to six months. 

I planted some lima beans this spring, but the plants produced only a few pods. Why? 

In the Midwest, yield is largely determined by weather conditions. Lima beans grow best when temperatures are between 70 and 80 F. They also require 1 inch of water per week (either from rain or irrigation) during blossoming and pod development. Hot, dry conditions during blossoming may cause many of the flowers to drop off without setting pods. Excessive nitrogen fertilization promotes lush growth, but also may inhibit pod formation. 

While both bush and pole lima beans are available, bush-type varieties usually perform better than pole varieties in Iowa. Suggested bush-type varieties for Iowa include Fordhook 242 (large greenish white seeds, heat tolerant) and Henderson Bush (small white seeds, early maturing). 

What is the proper care for amaryllis bulbs in fall? 

Plants that are outdoors should be brought indoors in mid-September. In order to bloom, amaryllis bulbs must be exposed to temperatures of 50 to 55 F for a minimum of 8 to 10 weeks.  This can be accomplished by inducing the plants to go dormant and then storing the dormant bulbs at a temperature of 50 to 55 F. To induce dormancy, place the plants in a cool, semi-dark location in late September and withhold water. Cut off the foliage when the leaves turn brown. Then place the dormant bulbs in a 50 to 55 F location for at least 8 to 10 weeks. After the cool requirement has been met, start the growth cycle again by watering the bulbs and placing them in a well-lighted, 70 to 75 F location. Keep the potting soil moist, but not wet, until growth appears. The other option is to place the plants in a well-lighted, 50 to 55 F location in fall.  Maintain the amaryllises as green plants from fall to early to mid-winter. After the cool requirement has been met, move the plants to a warmer (70 to 75 F) location. 

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