Garden Talk: July 19, 2007
From NGA Editors
Organic Farming Can Feed the World
One widely held criticism about large-scale organic farming is that if all farmers grew crops organically they could not produce enough food to feed the world. Researchers at the University of Michigan set out to see if this belief is actually true.
Researchers compared yields of organic versus nonorganic production from a global database of 293 farms and estimated the average yield ratio (organic:nonorganic) of different food categories grown in the developed and the developing world. For most food categories, organic production yields were projected slightly lower than nonorganic yields in the developed world, but up to three times higher in the developing world. Models predict organic agriculture can produce enough food on a global per capita basis to sustain the current population and even a slightly larger one, without increasing the amount of land farmed.
The study also calculated the amount of nitrogen fertilizer that cover crops could supply compared to synthetic fertilizers. Researchers found leguminous cover crops could fix enough nitrogen to replace the amount of synthetic fertilizer currently in use. Not only can organic agriculture produce enough fertilizer and yields to feed people, the benefits of this farming system include less soil erosion, less habitat disruption, less groundwater pollution, and reduced greenhouse gas emissions.
For more information about this research go to: University of Michigan.
Clematis are well loved for their early spring and summer flowers, however there are varieties that not only start the season, they also end the summer with another flush of blooms. One of the best of these repeat bloomers is 'Veronica?s Choice'.
This beauty features huge, fully double, mauve flowers with lavender streaks. The flowers can reach 9 inches in diameter, and the vines climb to 6 to 8 feet tall. 'Veronica's Choice' blooms in late spring on old wood and again in late summer on new growth. The late-summer flowers sometimes emerge as single blooms. In fall, the fluffy seed heads offer interest as cut flowers for indoor arrangements.
?Veronica?s Choice? is hardy in USDA zones 3 to 9 and grows best in part sun on well-drained, moist soil. Prune for shape in spring before spring growth emerges.
For more information on ?Veronica?s Choice? clematis, go to:Wayside Gardens.
New Organic Fertilizer
Midsummer is a good time to give your vegetables and flowers a boost of fertilizer to get them through the rest of the growing season. Foliar fertilizers are good to use at this time of year because they?re quick acting, and a new, non-smelly formulation derived exclusively from catfish promises to be popular with organic gardeners.
MultiBloom organic fertilizer -- with a nutrient analysis of 2-3-1 -- is a by-product of the commercial catfish farming industry in Mississippi. Unlike synthetic fertilizers, 40 percent of the nitrogen is readily available for plant use now, and 50 percent will be available over the next 15 weeks. Even though it?s derived from catfish, MultiBloom doesn?t have a strong fish odor. It doesn?t burn plant leaves and is soluble enough to be used in drip and overhead irrigation systems.
For more information about MultiBloom fertilizer, go to: MultiBloom.
The Best Lamb's Ears
Lamb?s ears (Stachys) are popular perennials known for their soft, silver leaves and flower spikes. There are two common groups of Stachys available. The ground cover lamb?s ears, such as Stachys byzantina, feature wide, soft, fuzzy leaves and 12-inch-tall, violet-colored flower spikes. The taller species, such as Stachys monieri, are also known as betony. They feature 2-foot-tall spikes of violet-colored flowers that rise above bushy mounds of green leaves.
The Chicago Botanic Garden evaluated 22 types of lamb?s ears for ornamental traits, disease and pest resistance, adaptability, and winter hardiness. Based in USDA zone 5, the Chicago Botanic Garden conducted the trial over a six-year period. Among the fuzzy-leaved lamb?s ears, the Stachys byzantina 'Big Ears', S. byzantina 'Cotton Boll', S. byzantina 'Silver Carpet', and S. byzantina 'Wave Hill' received the highest scores. Stachys monieri 'Hummelo' received the highest rating of the betony-type lamb?s ears. It features dark green leaves and violet-colored flowers that last into August.
For more information about this trial, go to: Chicago Botanic Garden.