Natural Garden Pest Control

They may already be infected. If not, they will attract predators. Pull the plant and dispose of it away from the garden area.

Natural composting methods, mulching, and top-dressing your soil with compost or natural fertilizer is the best way to develop strong, vigorous plants. Read more about How to Build and Nourish Healthy Garden Soil.

Practising no-dig or no-till gardening will help minimize the introduction of pests to the soil and increase the beneficial microbes.

Seaweed contains trace elements such as iron, zinc, barium, calcium, sulphur, and magnesium, which promote healthy development in plants. Seaweed fertilizer in mulch or spray form will enhance growth and give plants the strength to withstand disease. Seaweed mulch also repels slugs.

Clear your garden area of debris and weeds, which are breeding places for insects. Use clean mulch.

Insect pests are often plant specific. When plantings are mixed, pests are less likely to spread throughout a crop. Rotating crops each year is a common method to avoid re-infestation of pests that have over-wintered in the bed.

Water early so foliage will be dry for most of the day. Wet foliage encourages insect and fungal damage to your plants. See our page on drip-irrigation for methods of delivering water to the root systems without wetting the foliage.

If you’ve been working with infested plants, clean your tools before moving on to other garden areas. This will reduce the speed of invading insects.

When we move plants from one garden to another, we can also transport pests and disease. Be sure to purchase plants and soil amendments from a trusted source to ensure any introductions are clean and disease (and pest) free.

While snakes may not be everyone’s favorite visitor, garden snakes help control small rodents, slugs, grasshopppers, and more. Learn about the beneficial snakes in your area and do what you can to increase their habitat in and around your garden. For more information, read These 3 Snakes Are Your Garden’s Best Friends.

These common insects consume aphids, mites, whiteflies, and scale. Planting members of the daisy family (Compositae), tansy, or yarrow will attract them to your garden. Ladybugs are also available from online catalogue.

Lacewings are avid consumers of aphids, and their larvae eat aphids and other varieties of other insect pests. They are attracted to “composite” flowers, such as yarrow, goldenrod, black-eyed Susans, and asters. Lacewings can also be purchased online at the sources listed below and released directly into your garden.

Hover-flies are avid consumers of aphids, and the larvae of hover-flies eat aphids and other insect pests. Like the Lacewings, they are attracted to “composite” flowers, such as yarrow, goldenrod, black-eyed Susans and asters. Seeds for these flowers are available online or at most garden centers.

These large insects have an appetite for most garden pests. Praying mantis eggs are set out in the garden where they hatch and quickly grow to adult size. The eggs are available through mail order and online catalogues.

Nematodes are effective against cutworms, a common pest that destroys sprouts before they can grow into seedlings. Nematodes are also effective against beetles and root weevil larvae.

Nematode eggs are microscopic and come in a small sponge a million at a time. These are mixed with water and applied to the soil, where they hatch and go to work. If they get on foliage, wash them off to the ground.

Nematodes are harmless to humans and pets. They are available in some garden centers, through mail-order catalogues, and at the businesses linked below.

You can set aside a small garden plot of flowering plants designed to attract and harbor beneficial insects. These ‘good’ insects prey on many common garden insect pests and offer the gardener a safer, natural alternative to pesticides. Read our guide for more information about creating a Garden Mini Insectary.

For lawn or garden grubs, there is a natural, effective remedy called milky spore. The granules are spread on the soil and cause the grubs to contract a disease that kills them. This natural control affects only the grubs, leaving the beneficial organisms unharmed. Milky spore multiplies over time and will sit inactive, waiting for grubs to infect. One treatment is said to last 40 years. The grubs are actually the larvae of Japanese beetles. So, when you kill the grubs you kill the beetle.

Mix two tablespoons of hot pepper sauce or cayenne pepper with a few drops of Ivory soap into a quart of water. Let stand overnight, then stir and pour into a spray bottle and apply as above. Shake container frequently during application.

Sprinkle diatomaceous earth over plants and around edges of garden beds. The diatoms particles are very small and sharp – but only harmful to the small exoskeletons of insects, slugs and snails. Insects cannot become immune to its action, as it is a mechanical killer – not a chemical one. Read more about Diatomaceous Earth: Non-toxic Pest Control for Your Home and Garden.

For more information about nontoxic slug and snail control, read our article Natural Slug Control.

Use potato slices as bait to help clear the soil of wireworms before planting. Simply place potato slices in your garden on the soil surface: the potatoes will draw out the wireworms, which you can remove along with the potatoes.

Mix two tablespoons of baking soda into a gallon of water. Pour into a spray container and spray affected areas. Repeat this process every few days until problem ceases.

Mix equal parts milk and water and spray on infected plants. Three treatments a week apart should control the disease. Neem oil spray can also be quite effective against powdery mildew.

Combine one tablespoon of cooking oil, two tablespoons of baking soda, and a few drops of Ivory soap into a gallon of water. Pour into a spray container and apply as above.

Lime sulfur and dormant oil, available at nurseries and garden centers, can be sprayed on the trunk and branches of dormant fruit trees. This concoction will suffocate insect egg cases. Because the oily spray is heavy compared to the other water-based sprays, you’ll need a pump sprayer. These are fairly inexpensive and are available to rent from some nurseries. Only use this method while the tree is dormant, however, or it can kill the tree.

Commercial dormant oils may contain petroleum oil or kerosene. A less toxic method is to make your own. Mix 1 cup of vegetable oil and 2 tbsp of liquid soap in one gallon (4 liters) water. Mix the soap and oil first, then add the water. Shake often during use.

Monitor carrot rust fly arrival using yellow sticky cards. Delay your planting until after the first generation of rust fly has passed. After planting your crop, watch the sticky cards for signs of the adult rust fly. When they appear, cover your carrot row with floating row covers. For more details, read Carrot Rust Fly: Combat This Carrot Killer Using a Few Simple Tricks.

After transplanting seedlings into the garden (or after seedlings emerge), monitor the garden bed for the presence of adult flies using yellow sticky cards. If you detect adults, check the base of your plants for maggots and remove as soon as possible. If plants wilt, check for damage and remove maggots (if damage is minimal) and plants (if damage is more extensive). Do not compost. You can also use paper collars if growing a few plants, plant later in the season to avoid the insect’s peak, encourage beneficial predators like ground and rove beetles, or use floating row covers before adults arrive. For more details, read Chaos in the Cole Crops: How to Control Cabbage Maggots. Or learn about how to limit maggots in compost.

Encourage beneficial insects to inhabit your garden by planting and encouraging nearby companion plants. You can also buy beneficial nematodes that prey on cutworms, use plant collars made from recycled plastic containers, and eliminate alternate hosts that may keep these pests thriving nearby. For more details, read How to Control Cutworms in Your Garden.

Apply the bacteria B. popilliae, otherwise known as milky spore, when the soils have warmed to 65 degrees Fahrenheit or greater. Apply one teaspoon to your lawn or garden every four feet, in rows four feet apart, then water into the soil. The milky spore powder attacks Japanese beetle grubs and will be effective in the soil for approximately 10 years. For more details, read our article Milky Spore Controls Japanese Beetles in the Yard and Garden.

These biological mating scents attract insects to a trap that is coated with a sticky substance. Pheromone traps are effective, but remember they are “attracting” the insects – be sure to position them on your garden perimeter or you’ll attract outside pests into your garden! Available at larger garden centers, usually in the $5 – $15 range.

Floating row covers consist of lightweight opaque material, which is draped over the garden bed. Sunlight and water go through, but insects and birds are kept out. The material is so light that the growing plants simply push it up as they grow. The edges of the row cover need to be anchored with rocks or boards or the wind will lift it. The material is “spun,” which resists tearing, but it usually begins to break down after a few years. It’s also nest fodder for mice, so be sure to hang over the winter or store in a rodent-proof container. Row cover material comes in rolls so you can make a continuous cover no matter how long the garden bed.

Row covers are great for protecting seedlings. They are even more useful throughout the growing season when placed over vegetables such as carrots, beets, broccoli, Swiss chard, and spinach because they makes an effective barrier against flying insects looking for these plants to lay their eggs on.

A cloche is like a miniature greenhouse for your seedbeds and young plants, and acts as a barrier against pests. Unlike the floating row cover, however, the cloche has to be opened on hot days and for watering, and this presents an opportunity for pests to find the plants. But because the cloche helps seedlings and young plants get well established, the enhanced natural resistance of stronger healthy plants is the best defence against pests and disease. Click here for more info or for plans to build your own portable garden cloche.

Scraps of waxed cardboard from milk cartons are a simple yet effective defence against cabbage moths. Cabbage moth larvae kill young sprouts of the Brassica family (broccoli, cabbage, Brussels sprouts, kale or cauliflower).

Cut into 2″ squares and slit one side into the center; make another small slit crossways. Open the slit and slide the square so the seedling stem is in the center. This prevents the cabbage moth from laying eggs at the base of the sprouts. Leave in place – as the plant grows it will simply push the slit open wider. Be sure to apply as soon as the sprout appears, or the moth will beat you to it!

Mix one whole egg with a quarter cup of water and mix well. Pour the mixture into a pump bottle and spray it on your plants. This deterrent will withstand light rains because the egg sticks to the leaves.

Mix one tablespoon of liquid dish detergent with one ounce of hot sauce in one litre of water and spray directly on plants which deer have been nibbling.

For larger volume applications, mix the following ingredients:

• 1 cup milk
• 2 gallons water (8 liters)
• 2 whole eggs
• 2 T cooking oil
• 2 T liquid detergent

Pour the mixture into a pump bottle and spray it on your plants.

Eventually, even the most persistent deer will become discouraged and look elsewhere for forage. Once they’re in the habit of feeding elsewhere, you may be able to let up on the spraying regimen.

For more information on deer control, read How to Keep Deer Out of Your Garden.