Got Mildew? Get Milk!
by Arzeena Hamir
Less than 3 years ago, researchers in South America discovered a new alternative to controlling powdery mildew. Wagner Bettiol, a scientist from Brazil, found that weekly sprays of milk controlled powdery mildew in zucchini just as effectively as synthetic fungicides such as fenarimol or benomyl. Not only was milk found to be effective at controlling the disease, it also acted as a foliar fertilizer, boosting the plant’s immune system.
Powdery mildew in the cucurbit family is caused by the organism Sphaerotheca fuliginea. It is a serious disease that
occurs worldwide. For decades, organic gardeners had
to rely on making a spray from baking soda to control
the disease. Now, instead of measuring out the baking soda and combining it with a surfactant (a “sticking” substance) of either oil or soap, gardeners need only head for their refrigerators.
In his experiments with zucchini plants, Bettiol found that a weekly spray of milk at a concentration of at least 10% (1 part milk to 9 parts water) significantly reduced the severity of powdery mildew infection on the plants by 90%. While some gardeners may be tempted to increase the concentration of milk for more control, Bettiol found that once concentrations rose above 30%, an innocuous fungus began to grow on the plants.
How does milk control powdery mildew?
The scientist isn’t 100% sure how milk works to control this disease. It seems that milk is a natural germicide. In addition, it contains several naturally occurring salts and amino acids that are taken up by the plant. From previous experiments using sodium bicarbonate, potassium phosphate, and other salts, researchers have found that the disease is sensitive to these salts. It is possible then, that milk boosts the plant’s immune system to prevent the disease.
Milk used around the world
The benefits of using milk to control powdery mildew haven’t been isolated to Brazil. Melon growers in New Zealand are saving thousands of dollars every year by spraying their crops with milk instead of synthetic fungicides. The melon growers in New Zealand have been so successful that the wine industry is taking notice and beginning experiments using milk to control powdery mildew in grapes.
What kind of milk should be used?
In Bettiol’s original experiment, fresh milk was used, straight from the cow. However, this is obviously not feasible to most home gardeners. The research work in New Zealand actually found that using skim milk was just as effective. Not only was it cheaper, but the fact that the milk had no fat content meant that there was less chance of any odors.
Wagner Bettiol’s original article was published in the journal Crop Science (Vol.
18, 1999, pp. 489-92). It can be found on-line at:
Arzeena Hamir is an agronomist and President of Terra Viva
Organics. When she’s not planting peas or picking zucchini,
she answers questions about organic gardening at: [email protected]
The Green, Green Grass of Home
by Don Trotter
Hello fellow Earthlings, and welcome to the front yard.
This time our discussion will focus a bit on that lovely
chunk of green, manicured monoculture called Lawn. So
let’s take a stroll onto that green carpet and think a
bit about toxic runoff and the health of our families.
A lush, verdant green
lawn is part of American culture. We spend hours trimming
and mowing so that our green carpet is better looking
than anyone else’s is. Advertising bombards us where
a couple of neighborhood gorillas make fun of the poor
sap with the brown lawn area. So he goes down to the
garden center and picks up five hundred dollars worth
of super chemicals to make his lawn perfect. Just like
the stuff Bubba uses.
The Natural Lawn
The natural lawn can really
be the envy of the entire neighborhood. The techniques
used to grow nutritious vegetables, succulent fruit,
and stunning ornamentals easily translates to turf care.
When we focus on promoting biological diversity in the
soil beneath our turf grasses instead on annihilating
everything alive within a square mile our lawns can
be better, cheaper to maintain, and at least as green
A natural lawn grows in
soil that is alive and whose roots can reach deeper
thanks to earthworms and other garden helpers. The natural
lawn doesn’t stress as easily in extremely hot or cold
weather and doesn’t need watering as often because the
soil and all of its organic matter hold onto water better.
A natural lawn doesn’t require feeding every week or
two, and most natural lawns only require two feedings
per year. A natural lawn supplies the rest of the garden
with super fast compost and stays green all the while.
What to do With the
Grass clippings are a
rich source of valuable nitrogen to the lawn and to
the compost pile. The new mulching mowers that have
become so popular these days actually double chop the
clippings and return them to the lawn to be eaten by
beneficial microorganisms or by Aristotle’s plows of
the Earth (earthworms). In the compost heap those grass
clippings can speed up the decomposition of other harder
to decompose materials making your compost ready to
I have also spoken to
gardeners that save their clippings until they prepare
the soil for their vegetable garden, they just add the
clippings along with the other minerals and till it
right into the soil. I like this idea very much. Using
grass clippings as a soil conditioner is a very good
idea. Grass clippings can be used in many places in
the natural garden and should not be disposed of even
if you are not inclined to make your own compost.
Got Questions? Email the
Doc at [email protected] Don Trotter’s Natural
Gardening columns appear nationally in environmentally
sensitive publications. Look for Don’s books Natural
Gardening A-Z, and The Complete Natural Gardener, both
from Hay House (http://www.hayhouse.com) at bookstores and on line everywhere.
by Arzeena Hamir
There are very few things that I like to plant in my garden
that carry the name “hairy” but vetch is definitely one
of them. Hairy vetch, Vicia villosa, is an annual legume
that when planted as a cover crop, creates a lush layer
of feathery leaves. It tolerates a wide soil pH range,
from 4.9 to 8.2 but does best when pH is from 6.0 to 7.0.
The seeds are not very common so why do I go out of
my way to plant it? In ideal conditions, hairy vetch
can fix up to 100 lbs of nitrogen per acre and the soft
leaves break down extremely fast, providing a boost
to whatever crop is grown after it. If left on the surface
during the growing season, the vetch will smother out
any competing weeds and help to conserve moisture.
Hairy vetch grows well
on most soil types, but is most adapted to loamy or
sandy soils. Each plant produces from 3-10 stems, which
vine their way over the soil, usually growing to 3ft
in length. It is hardy up to Zone 4 and produces a purple
flower that attracts many beneficial insects such as
Seven-spotted lady beetles and big-eyed bugs.
Most often, hairy vetch
is planted as an overwintering cover crop and is seeded
between July and mid-September. The earlier the seeding
date, the more time the vetch has to establish a cover.
Once temperatures drop below 50 degrees F, very little
Nitrogen is fixed by the soil Rhizobia and it normally
takes 3 weeks after planting for the nodules to form
on the vetch roots. To ensure that the maximum amount
of nitrogen is fixed, the seed should be coated with
a pea/vetch inoculant prior to planting.
In states like Ohio &
Minnesota where vetch will winter kill, it can either
be planted as an early fall crop or seeding in the spring
for a summer cover crop. When seeded in May, the plants
will flower by July and can then be incorporated. When
seeded in the spring, care does need to be taken around
heat-loving crops since the cover that the vetch provides
will actually cool the soil, slowing down growth for
plants like cucumbers & peppers.
in the Pacific Northwest, a common practice is to mix
hairy vetch with fall rye or oats. The cereal plants
establish quickly and absorb any residual nitrogen that
would otherwise be leached away during winter rains.
In the springtime, the hairy vetch takes off and uses
the rye or oat stems as a support to climb on. When
both are turned over into the soil, the soft leaves
of the vetch help to break down the more fibrous stalks
of the cereals and allow nutrients to become available
much faster. Research has shown that a combination of
hairy vetch and rye or wheat would provide more winter
soil cover and a larger yield of organic material than
hairy vetch alone.
Hairy Vetch Beats Black
In an experiment in Beltsville,
Maryland, researchers compared the yields of tomatoes
when grown using a hairy vetch living mulch versus other
clovers, black plastic mulch, paper mulch and no mulch.
Yields of the tomatoes were more than double that of
the unmulched plants and were significantly higher than
even the plants that were grown with black plastic.
The scientists found that
hairy vetch helped reduce soil erosion, water evaporation,
and moderated the soil temperature. The vetch cover
also eliminated early weed competition and released
nitrogen to the tomato plants over a long period of
time. Further testing has also found that growing tomatoes
in an organic mulch of hairy vetch also reduced damage
from Colorado potato beetle. Yields of tomatoes just
grown with hairy vetch were comparable to those of tomatoes
grown using insecticides.
Some Words Of Caution
As wonderful as the plant
is, there are a few drawbacks. Hairy vetch seed usually
contains anywhere between 15-30% hard seed which will
not germinate the year it is planted. I commonly see
vetch plants poking their way up around my garden years
after I seeded the area with vetch. In addition, when
it’s not grown with a cereal crop, the dense mat that
the leaves form can harbor aphids, tarnished plant bugs,
armyworms, and cutworms.
However, if these points
are kept in mind and the vetch is combined with a cereal
crop, I think it’s still worth growing. Not only will
the vetch provide almost all the nitrogen needed for
my vegetable garden, its uses as a weed suppressing
mulch and safe haven for ladybugs still make it a favourite
in my garden.
For more information on
Hairy Vetch, here are a few University websites:
Arzeena is the Contributing Editor – Vegetable Gardening at http://www.suite101.com/join.cfm/47083