UNIVERSITY PARK, Pa. -- When Jack threw three magic beans into soil, a beanstalk reaching the heavens grew overnight. While beans aren't quite that easy to grow, a vegetable expert in Penn State's College of Agricultural Sciences says even first-timers who don't know beans about gardening can raise a top bean crop.
"If you can prepare soil with a hoe and read a seed packet, you can grow beans," says Pete Ferretti, professor of vegetable crops. "Bean plants are nearly impossible to transplant, so gardeners have to raise plants by direct seeding in the garden's soil."
Ferretti says beans should not be planted before soil temperatures reach 65 to 75 degrees Fahrenheit during the day. Also, temperatures should not fall below 60 degrees at night. "In most years in Pennsylvania, that means you'll be planting in mid- or late May," he explains.
Two exceptions to the May planting rule are lima beans and fara beans. Limas should be planted in early June and fara (English broadbeans) as early as St. Patrick's Day.
Bean plants can be overtaken easily by weeds, so Ferretti suggests heavily mulching the garden, then clearing a 6-inch swath to sow the seeds. The soil should be thoroughly cultivated and seeds should be sown about 1 1/2 inches deep into the soil.
"Turn the hoe upside down and use the handle end to trace a furrow into the soil to attain the perfect planting depth," Ferretti says.
Seeds should be placed about 2 inches apart during planting. When the plants have started growing, Ferretti recommends removing less successful plants, so each plant has about 4 inches of space on each side.
Ferretti says most gardeners prefer growing two types of snap beans:
--Climbing or pole beans. These varieties require a trellis, a teepee-style pole structure or nylon netting so the bean plant will grow upward. "These varieties are for more experienced gardeners," Ferretti says. "Pole beans let you use garden space more effectively, but it's more work to grow them."
--Bush Beans. "Weekend gardeners should choose these varieties," Ferretti says. "They're easy to handle, you can harvest them four or five times, and then you can pull them out and put in a late crop, such as cabbage, cauliflower, endive or sweet corn."
Pennsylvania's heavy, clay-rich soil can prevent bean plants from sprouting if the soil becomes crusted over. Ferretti suggests lightly tapping the soil using the back of the rake as a tamper, then adding some vermiculite or sand in the indentations to keep the soil loose.
To prevent soil compaction further during seeding, gardeners also can adapt 1-by-12 scrap lumber to walk or kneel on when working in the garden.
Bean plants don't require much fertilization. Ferretti says any fertilizer should be added at planting (following recommendations from a garden soil test or using about 1 1/2 pounds of 5-10-10 fertilizer per 100 square feet), then raking it into the planting furrow.
Some of the diseases affecting beans include blue mold, downy mildew, mosaic virus and anthracnose. Ferretti says most seed catalogues carry bean varieties that are resistant to one or more of these diseases. "Don't plant beans or other legumes such as peas in the same spot every year," Ferretti says. "That can encourage more disease problems."
Ferretti says beans, depending on the variety, grow to maturity after 45 to 72 days. Most bush bean varieties can be picked after 55 to 60 days. "Don't pick beans when it's wet or dewy in the morning," he says. "You can spread viruses and bacterial diseases by breaking tiny, moist leaf hairs and touching other plants."
Judging when fresh beans are ripe is a snap -- literally. Ferretti says a ripe fresh bean will make a sharp snapping sound when broken. "If the beans are too small, they'll be very pliable like a rubber band," he explains. "If too old, they'll be very firm and waxy, showing distinct seed bulges within the pod."
Ferretti says gardeners can find bean varieties in colors other than green or yellow. Some heirloom or imported varieties can be pink, speckled, jet black, red-and-white, white or purple.
"They look great in salads or other recipes," he says.
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EDITORS: Contact Pete Ferretti at 814-863-2313 or pferretti@psu.edu.
Contact: Jeff Mulhollem jjm29@psu.edu 814-863-2719 814-865-1068 fax #176