The Seasons of the Garden column shares seasonal gardening information and tips with MOTHER EARTH NEWS readers.
Seasonal Gardening: A Greenhouse Hot Compost Pile
A fresh compost pile in a home greenhouse can provide heat and CO2 , increasing both the yield and vigor of indoor plants. And maintaining a hot heap doesn't have to be a grueling chore.
Bob Kornegay worked out the secrets of greenhousing with compost in two winters of gardening in the multipurpose green-house/bioshelter at MOTHER'S Eco-Village. In Bob's design, compost bins were built directly under his plant beds, so that the pile's heat would warm soil instead of air. That way the plants kept growing well even on the coldest winter days.
The carbon dioxide given off by the pile removed a common limitation on greenhouse plant growth—lack of atmospheric carbon for photosynthesis. (An unvented greenhouse can use up all available CO2 , by mid-morning.) The end result: Bob's crops produced more prolifically than ever and were so healthy they had no pest problems. If you've ever raised crops in a greenhouse yourself, you'll appreciate what an achievement a no bug greenhouse is!
Having to start a new compost pile every time an old one cools down is a big chore. But Bob soon learned that if he mixed fresh manure or calcium nitrate into a cooling pile, the extra nitrogen would boost bacterial activity. The pile would "kickstart" itself and give off lots of heat for a couple more weeks.
Bob solved another problem: ammonia. When a pile first heats up, it releases ammonia gas, which can wipe out crops in a closed-in greenhouse. Bob's answer was to build only one new compost pile every winter (his kickstart technique was the key to that), and to construct it before the weather got cold so he could vent the greenhouse thoroughly during the ammonia stage. With those problems licked, Bob found indoor composting to be a key to indoor growing success.— PS.
Seasonal Gardening Research Briefs
Treat roots right. A Third World horticultural worker used an innovative technique to transport over 300 bare-root fruit trees from the U.S. to Africa with no losses. He dipped the roots in water to remove dirt, sprayed them with a 1:1 mix of hydrogen peroxide and water, and covered the roots (not the tops) with plastic bags for shipping. The peroxide apparently released oxygen for root use and might help increase the survival rate of any bare-root transplants.
The BT gene? Scientists at Plant Genetic Systems in Belgium report that they have successfully incorporated a gene from the biological bacterial control Bacillus thuringiensis into tobacco plants. Caterpillars that ate leaves of plants with the BT gene became paralyzed within 48 hours and died within three days.
Ionize your tomatoes! Greenhouse trials have shown that a high density of negatively charged ions in air (generated by high-voltage ion emitters) can result in faster growing, earlier-maturing, and higher-yielding tomato plants. The ion-exposed tomatoes generally had higher concentrations of vitamin C and minerals . . . and were judged better-tasting, to boot.
Good crabs. Ornamental crab apples can make excellent low-maintenance landscape plants, but only a few varieties show significant disease and pest resistance. According to recent trials, Donald Wyman, Ormiston Roy, and Snowdrift resist scab, cedar-apple rust, powdery mildew, and plum curculio damage. The first two varieties resist fire blight, as well.
Oak away potato beetles. Researchers at the University of Rhode Island have found that alcohol extracts of white oak leaves and bark (particularly the bark) inhibit feeding by Colorado potato beetles. Apparently, the tannin in the oak parts completely stops beetle feeding even when it's applied in very small amounts.
Save lawn water. Some Kentucky bluegrass varieties use 50% more water than others. Test results from the University of Nebraska indicate that Enoble, A-20, Adelphi, Newport, and Baron bluegrass need a lot less water to prosper than South Dakota, Bristol, Bonnieblue, Nugget, Majestic, Birka, Sydsport, and Merion.
EDITOR'S NOTE: Greg and Pat Williams raise most of their own food on a small farm and publish HortIdeas, a fine newsletter on gardening research and products (available for $10 a year from G. & P. Williams, Gravel Switch, KY).