CHEMICAL-FREE GARDENING
Harry Jongerden
Cobourg 14/04/2004
We’re going to talk about growing healthy and beautiful gardens - and you won’t need any
chemicals!
#1) SOIL: We always begin with soil. There’s nothing more important to the health of our
plants than the soil they grow in. Many buildings and houses have foundation planting or beds with
the plant material growing in excavated subsoil. Modern buildings are the worst culprits.
Get “triple mix” topsoil. Never buy or add regular “topsoil”, not even to mere shrub beds if you can
afford it. Triple mix topsoil costs twice as much, but it’s the only way to go.
Alternatively, add manure or compost to your existing soil. It’s as expensive as triple mix at
$25 per cubic yard, but once you’ve established good soil in a garden, you can maintain its health with
composting, or by adding shredded leaves every fall. Healthy soil produces healthy plants.
#2) WATERING: Watering correctly is very important to maintaining healthy plants. You
really don’t have the option of allowing ornamental plants to go dormant in drought conditions. There
are some plants which survive a lack of watering, but a lot of us wouldn’t be satisfied with the limited
plant choices of a drought-tolerant garden.
Plants don’t like a shallow watering. Roots are deep so you need to water deeply. For
ornamental plants, water every third day, giving them about 1” of water. You can measure that by
putting out a pan to catch the water coming out of your system. When it’s got an inch in there, you’ll
know how long your sprinkler takes to put out 1” of water.
Water in the morning, if possible. Watering in the heat or bright sun is hard on plants.
Watering late at night creates moist opportunities for fungal diseases and slugs. A morning watering
gets moisture into the ground and allows the plant’s foliage to dry off as the sun hits it. That being
said, it’s difficult to water everything in the morning. 2nd best would be early evening when the worst
of the heat is past and the plants have a chance to dry off before sunfall.
Watering artificially, the way we do with our hoses and sprinklers, is a tricky thing. For one
thing, tap water’s too cold. Too much or too little can lead to fungal diseases, and doing it at the
wrong time of day can also be harmful. There’s nothing better than a good natural soak.
#3) DRAINAGE: We’ve covered the water above. Now let’s talk about the water below. A
lot of ornamental plants hate to have their roots sitting in water, especially roses. Poorly drained soil
can be a problem. Plants that require good drainage will always be unhealthy in a wet site. If you dig
down a foot or two and water pools in the hole you just dug, you’ve got problems. Either get going
with some gravel and drainage pipe to carry that water away, or plant accordingly. There are a
number of ornamental plants that can tolerate a heavy, poorly drained site. Just don’t try planting
roses there.
One other option in a poorly drained location is to plant on raised beds. Build up the soil so
that the plants sit higher than the normal surrounding grade. Raised beds have helped many
gardeners avoid costly and time-consuming drainage installation.
plants
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b)
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d)
#4) PLANT CHOICE: Get out some helpful books and/or seek advice. Choose the right
for the conditions. Choose plants:
according to the amount of sunlight available
according to soil conditions
according to your ability to give them enough water or attention
according to their hardiness (i.e. cold tolerance, disease resistance, etc.)
There are so many informative books and catalogues to help us make these choices. Research
is always worth doing, and beautiful books and catalogues get us through many a long cold winter.
Remember, choosing inappropriate plants will eventually give you unhealthy plants unable to thrive.
They’ll get diseases, bugs will damage them, and you’ll be looking for solutions to a problem caused by
poor planning.
At this point we can all hang our heads in shame. Because I suspect there’s none of us here,
myself included, who haven’t put the wrong plant in the wrong place. We’ve all eyed something we
just had to have and then proceeded to slowly kill it by planting it somewhere it didn’t belong. We’re
all a bit foolish for having planted Hybrid Tea roses when we know they’re going to attract aphids, get
powdery mildew and drop their black spot- infested leaves. So let’s look at some ways to clean up
these problems and make ourselves feel better about our gardening abilities.
NON-CHEMICAL SOLUTIONS:
1)
Dormant Oil: Dormant oil is an excellent treatment for woody plants to kill overwintering
insects and the spores of fungal diseases. It’s called “dormant” oil because you can’t ever spray it on a
plant with the leaves showing, only on a dormant plant with tight unopened buds. Putting this mineral
oil on leaves can damage them severely. So, late March or early April, spray dormant oil on things like
roses, fruit trees, or on honeysuckle vines. It really helps keep down powdery mildew, black spot, or
in the case of fruit trees and hollyhocks, rust.
2)
Compost Tea: My other main recommendation for combating fungal diseases is Compost
Tea. This isn’t something you spray on your plants when you see the white-grey mildew withering
away the leaves. Compost Tea is a preventative spray to be applied to any plants, particularly those
plants prone to fungal disease. Start in late May and reapply every two weeks until late August.
We’re applying a supercharged concoction of microbial activity to the plants. It acts as an
inoculant against fungal disease. Scientists aren’t sure if the microbes attack the fungal spores, or just
keep them in check, but the fungal spores don’t take over and wipe plants out the way they do if left
unchecked.
I’ve sprayed with plenty of chemicals to fight powdery mildew, black spot and rust over the years.
Even using the whole chemical arsenal doesn’t prevent these diseases from beginning and spreading.
You’ll see some of these diseases on the susceptible plants despite using Compost Tea, but the tea
works at least as well as the chemicals at keeping them in check. I would especially use Compost Tea
on Roses, Honeysuckle vine, Phlox paniculata, Hollyhocks, Monarda, Asters and anything else that
gives you trouble.
Compost Tea has been around for a long time but only recently has the science been done to
figure out how it works. Scientists have tried it as a replacement for fungicides on golf greens with
amazing success. It’s odd how golf courses can be pesticide-free in Europe but not here.
And what is Compost Tea? It’s water that’s had a shovelful of well-rotted manure or compost
steeped in it for five days. (5 parts water to 1 part compost) It may be called “tea”, but no heating is
required! Strain out the particles and spray the liquid on the plants. If you’re going to faithfully spray
every 10-14 days you need to be brewing up new batches to always have some at hand. But it’s really
simple.
3)
Baking Soda: If you find the notion of Compost Tea icky, a 1% baking soda solution also
works well. Some people combine it with a little vegetable oil to make it stick to the leaves better. As
with Compost Tea (and the chemical fungicides), this treatment should begin early in the summer and
be repeated every 10-14 days.
4)
How To Handle Insects: Easy. Avoid the pesticides such as Malathion or Sevin. These
chemicals work well, but you’re using a sledgehammer where a fly swatter will do.
Learn to tolerate a few bugs on the plant. Our biggest bug problems here are probably aphids
and spider mites. Aphids are easy to see and fairly easy to kill. Spider mites are tougher. They hang
out on the underside of leaves so when you spray for them you need to get down and spray from
below in order to hit them. In both cases, aphids and spider mites, you need to hit the bug, not just
the plant leaves and hope the bug moves into it. Direct contact is required.
There are many effective alternatives to chemical pesticides. Diluted garlic or hot pepper juice
work very well. There are many other folk remedies out there, including boiled rhubarb leaf water or
cabbage water. Lots of different books are filled with recipes and good advice, advice that you’ll
especially want to use in a vegetable garden.