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.
Quick Tips
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.
Tools and Resources
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.
