Theme: Gardening
for a Sustainable Future
Organic Matters
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Schoolers Creatively Combat Pests
Home
is school for Mary Pavlinchak's three children, and their
organic garden is a living science textbook. Inspired by their
grandmother's love of gardening and her penchant for pointing
out creatures and their interactions, Mary's children decided
to dig up the lawn and get to work.
They
hoped to bring to life their vision of an organic garden sporting
flowers and a host of butterflies. Together, they dug up the
whole lawn, discovering the scads of grubs that called it
home. Armed with organic gardening books, the kids tried to
create a healthy ecosystem and grapple with problems that
arose. Grubs in the lawn? Water it with a detergent solution.
Japanese beetles on roses? Concoct a spray made from blended
hot peppers and onions.
But
other, more complicated, challenges also arose. Although the
children had their hearts set on a butterfly garden, butterflies,
they realized, start as caterpillars. And they had already
observed that the caterpillars munching on their garden plants
were damaging the leaves. "The kids had to make a tough decision,"
notes Mary. "They decided to maintain a bird feeder filled
with black sunflower seeds to attract birds who, they speculated,
could help keep caterpillars in check. Together we discovered
that it's all about balance."
Mary
explains that the students derive many of their ideas for
promoting garden health and controlling pests from their favorite
book, Roses Love Garlic by Louise Riotte. They've tried burying
banana peels near roses to supply potassium (as the peels
decompose), using dissolved aspirin to prevent transplant
shock, and using soap sprays and other concoctions to control
pests. After experimenting with different approaches to pest
control, the children decided that companion planting took
less time and led to more interesting plantings. This approach
involves planting certain crops near others to repel pests,
attract (trap) pests, draw beneficial insects, or otherwise
protect a crop. When the young growers planted chives and
garlic near roses, the chives attracted aphids, who, the students
inferred, seemed to prefer them to roses.
"It
has been such a great learning tool because we try different
strategies in the garden and work hard to learn and meet challenges,"
says Mary. "When we moved and had to start gardening from
scratch in an entirely new environment, it was apparent how
much they'd learned about how to go about solving problems
and keeping plants healthy," she adds.
Buddy Plants, Beer, and Blenders:
Testing Pest Control Wisdom
Ask
gardeners about homegrown pest control and you'll get a slew
of creative responses: beer-filled dishes to attract slugs,
a spray of juiced bugs to deter insect relatives, marigolds
planted to repel nematodes, and so on.
Will
these strategies work in your school garden? Which are most
effective for which pests? What is the scientific explanation,
if any, for the effectiveness of each approach? Might any
techniques be harmful to plants or beneficial insects?
Such
questions are rife with possibilities for student inquiry.
Consider inviting your students to interview gardeners in
your community and/or examine books or Internet sites in search
of
suggestions
for companion plants and homemade pest remedies. Then set
up some investigations to test their effectiveness. Be sure
that your sleuths have observed carefully enough to see the
creatures that are actually doing damage and have positively
identified the culprits.
With
companion planting, pest control is often the aim, but better
space and nutrient efficiency can also result. Beneficial
insects, such as ladybugs, depend on pests for nourishment.
But when pests are in short supply, certain plants that offer
nectar and pollen offer these good guys an alternative food
source. Many of these are small-flowered plants that belong
to the carrot and daisy families (anise, dill, fennel, yarrow,
zinnia). Other companion plants repel harmful insects, or
attract them and draw them away from your precious plants.
The Canadian
Bugline Web site (www.winnipeg-bugline.com/comp_pl.html)
lists plants in these different categories. Consider experimenting
with some of these in your classroom garden.
Following
are some classic recipes for homemade insect sprays. Be sure
to have students test such solutions on a few small leaves
before starting a full-scale application and keep labeled
containers tightly sealed in a safe place.
Homemade
Soap Sprays. These
can be effective against soft-bodied insects such as aphids.
Dissolve 3 tablespoons of soap flakes (not detergent) in a
gallon of water and spray on plants.
Herbal
Insect Repellent. Gather
leaves from tansy, lavender, and sage, which have strong insect-repelling
qualities. You'll need an ounce of leaves from each plant.
Place the herbs in a 1-quart jar and fill it with boiling
water. Let it set until it cools. Or make an infusion by steeping
the herbs in a jar of water placed in a sunny outdoor spot.
Drain off the liquid and set this solution aside. Dissolve
1 teaspoon of soap flakes in 2 cups of water. Add 1/8 cup
of the herb solution and mix well. Use a sprayer to coat all
plant parts with the bug repellent.
Hot
and Spicy Spray. Some
gardeners combine hot peppers and garlic in a soapy solution.
Puree two hot peppers and two cloves of garlic in a blender.
Add 3 cups of water and 2 tablespoons of biodegradable liquid
soap. Strain and fill a spray bottle with the solution.
Bug
Juice. Although
it seems a bit macabre, consider using bug juice to fight
pests. Collect at least 1/2 cup of pesky insects and place
them in an old blender with enough water to make a thick solution.
Blend on high and strain out the pulp using cheesecloth or
a fine sieve. Dilute at a rate of 1/4 cup bug juice to 1 cup
of water, pour into a spray bottle, and apply to plants. (Some
scientists believe that pheromones from the blended insects
send a warning to their living relatives!)
Foiling Pests Naturally
Gardens,
as dynamic ecosystems, offer countless opportunities for curious
young observers to ask questions and pursue fruitful investigations.
If we jump at short-term solutions to "problems" that arise,
for example, by exterminating pests, children can lose the
opportunity to develop, through careful observation and experimentation,
a deeper understanding of the complex interactions among plants,
insects, weather, soil conditions, and human horticultural
practices. By understanding what makes our gardens and plants
attractive to insects and diseases, and how to maintain plant
and soil vitality, youngsters learn important lessons about
how to work with nature to create a resilient system.
The
best way to prevent pests from getting out of hand is to promote
healthy plants and soils. Here are some tips for doing so.
-
Rotate
your crops to different locations from year to year
-
Apply
compost or other organic materials annually to build soil
health
-
Provide
adequate spacing for plants within rows or beds and between
rows or beds
-
Plant
resistant varieties
-
Mulch
with organic materials
-
Clean
your garden by removing debris and infected plants minimizing
weeds that compete with garden plants
-
Prune
weakened foliage
-
Provide
proper plant nutrition using compost and/or organic fertilizers
(a lack or excess of nutrients, particularly nitrogen, weakens
plants)
-
Provide
consistent moisture for plants
-
Encourage
beneficial insects
If just
a few insect pests show up on plants, students can continue
to observe them, or simply pick them off and squish them.
Remember, healthy plants and insect pests can co-exist. A
few leaf holes aren't death for a plant. If students notice
pests that seem on the verge of or in the midst of destroying
entire crops, they might try knocking them off with a soapy
water spray or homemade remedy, trapping them, or introducing
beneficial insects.
Author: Eve Pranis