How homemade compost prevents fungal disease in gardens, as well as bleaching summer seeds, pest biocontrol, and lengthening the storage life of okra.
For several years, West German agronomists have been using liquid extracts made from compost as preventive fungicides for garden crops. Plants treated with compost extracts have shown enhanced resistance to various fungi that cause blights and mildews. Indeed, the extracts have successfully prevented late blight of tomatoes and potatoes; anthracnose and powdery mildew on grapes; botrytis blight of beans; and more. (The extracts won't cure infected plants—they are a preventive only.)
To make a batch of the extract, simply mix one part well-rotted compost (that contains a mixture of plant matter and animal manure) with six parts water. Stir well. Let the mixture stand for about a week, then filter it through cheesecloth. Spray the liquid (undiluted) on plants, or use it to soak seeds overnight.
The German researchers say that compost extracts cause surface concentrations of phenols (chemicals that are toxic to fungi) to increase considerably. This results in induced resistance to fungal infections. Extracts from compost containing (any kind of) animal manure result in much better resistance than ones from only plant material.
Plant resistance typically declines about seven to 10 days after treatment, so for best results, repeat applications every five to seven days.
Bleach summer seeds for better germination. To get good lettuce germination at high (85°–95°F) temperatures, first bleach the seeds. So say British researchers who soaked the seeds for a couple of hours in a 50°F solution with about 10% available chlorine. The result? Seeds that normally had a germination rate of under 10% (at 95°) had a 50% sprouting rate, and 40% germinators jumped to almost 100%. Apparently, bleaching slightly weakens the seed coat. Indications are that the technique should work on some other crops as well.
Roses: don't mess when stressed. North Carolinian Noel Lykins raises prize roses that are totally dependent on rainfall for moisture. He's found that during prolonged droughts, stopping all normal cultural practices (including fertilizing, pest control, pruning and even cutting flowers) results in best plant survival. When the roses show signs of recovery, he resumes regular care.
Pest control without insecticides: biocontrol's centennial. Does the idea of importing "good" insects to control "bad" ones still sound a little too novel or untried? Actually, the practice of biological control turns 100 this year. In 1889, cottony-cushion scale insects threatened to destroy California's fledgling citrus industry. USDA scientists imported 129 Australian vedalia beetles, which spread and completely wiped out the threat. Biocontrol was a standard method for pest—and even weed—control until the 1940s, when DDT and other insecticides entered the scene. Now, with rising concern for the chemicals' side effects (and diminished effectiveness), biocontrol is back.
Okra in the bag. According to Louisiana Agricultural Experiment Station researchers, storing okra pods in polyethylene bags does much more to lengthen storage life than quickly cooling them. To keep your okra fresh longest, store it in a plastic bag in the refrigerator.
Growers in the Pacific Northwest have had great success using shiny red and silver Mylar tape to keep birds away from ripening fruits. The 7/16-inch-wide tape is pulled out from the center of the roll so it spirals, then is staked around strawberry rows or hung on individual fruit trees. The tape is sold in 290-foot rolls. . . . A good source for such hard-to-find seed-saving supplies as silica gel, vials and desiccants is the Southern Exposure Seed Exchange (catalog available as a free PDF download) . . . . The video Beautiful Gardens With Less Water (Sunset Films and Television) includes tips on home landscape design for low water use, selection of irrigation equipment, and mulching techniques . . . . Many British growers have used translucent tubes called Treeshelters to promote the growth of seedling trees while also protecting them from wildlife. Now they're available in the U.S.
Greg and Pat Williams raise most of their food on a small farm and publish HortIdeas OnLine, an e-newsletter on gardening research and products.