The #1 key to keeping your organic garden pest and disease-free is to keep your plants as healthy as possible. Sounds too simple, doesn’t it? Time and time again, pests are more likely to skip over healthy plants and instead attack plants that are stressed in some way: dealing with extreme fluctuations in temperature or watering or soil that is compacted or missing crucial nutrients.
Follow these steps:
1. Create a nutrient-rich soil.
The more fungi, protozoa, earthworms and microorganisms in your soil, the richer/better the soil will be. Building a compost-rich soil will invite organisms to improve it further.
2. Rotate your crops every year.
Each crop depletes the soil of certain nutrients. As a result, moving them to a different location every year helps you manage the soil’s fertility. It also keeps the same crops from being reinfected year after year by remnants of disease left behind in the soil.
3. Keep your plants consistently watered.
If you see your plants sagging from lack of water, they are already stressed.
4. Use mulch to keep the soil consistently moist.
Mulch will decrease the evaporation of water in the garden.
5. Before buying plants, check for signs of disease.
If you buy plants from seed companies or garden centers, check them thoroughly for signs of disease before introducing them to your garden.
6. Protect your plants against weather.
Use garden fabric or tomato teepees to keep plants warm if temperatures should fall below their comfort zone.
7. Wash your hands and tools to avoid spreading disease.
Disinfect all garden equipment, plastic mulch, cages and stakes when you put them away for the winter. Also make sure to clean up and dispose of any diseased garden waste.
8. Buy disease-resistant plants and seeds.
If your neighbors have experienced issues with specific diseases, buy plants resistant to those diseases. (Hopefully your garden center will buy plants that are well labeled with disease-resistance information. Seed companies that ship plants have detailed descriptions of the plant’s disease resistance in their catalogs and online).
9. Avoid working in the garden when plants are wet.
Disease can spread more easily under these conditions.
10. Try companion planting.
This involves strategically planting specific herbs and flowers near certain crops. Companion herbs and flowers are known to produce odors that confuse pests, draw pests away from your crops or attract beneficial insects that prey on pests.
Not only do companion plants deter pests, many also enhance the growth of your crop. A great book on this topic is Carrots Love Tomatoes by Louise Riotte.
Examples of companion planting include:
- Planting tomatoes and basil together enhance the flavor of the tomatoes, but the basil also controls the tomato hornworm.
- Planting onions near your carrots will deter rust flies.
- Nasturtiums are effective as a trap for aphids, but also deter cucumber beetles, squash bugs and whiteflies.
11. Sit back and let other organisms do the work for you!
Utilizing living organisms like parasitic nematodes, microbial pesticides and beneficial insects and animals is an effective form of pest control.
An effective, inexpensive tool for keeping your garden pest-free is to attract native, beneficial birds, insects and animals to manage pest populations.
Birds - If you provide places for them to nest as well as food and water, birds will make themselves at home and eat large amounts of insect pests.
Snakes - Non-poisonous snakes, like brown, grass and garter snakes) consume snails and slugs.
Toads - Toads consume 15,000-20,000 insects per year, which include flies, cutworms, grasshoppers, grubs and slugs. This year, we are making an effort to attract toads to our yard by building some simple toad houses. You can find a Toad House at garden centers, but they can also be easily made.
Examples of these include:
- Milky Spore is a naturally occurring microscopic bacteria (Bacillus popilliae) that kills Japanese beetle grubs before they can grow into adults.
- Grub Guard – Grub Guard beneficial nematodes are naturally occurring microorganisms that kill Japanese beetle grubs without harming pets or beneficial insects.
Many of the insects in our environment are actually unsung heroes of our garden.
Bees - Bees are crucial to the pollination of both cultivated crops and wild plants.
Ladybugs (Lady Beetles) - These cute insects are great protectors of our gardens consuming spider mites, aphids and mealybugs. It is possible to buy large amounts of these beneficial insects, but you are better off trying to attract them to your garden instead of purchasing them. If your garden is not a great place for them to live, your newly purchased ladybugs will find somewhere else to live.
Yellow Jackets - I’ve often wondered if there is any purpose for these insects on earth, other than being here to terrify me. It turns out that yellow jackets feast on caterpillars, flies and other larvae.
Parasitic Wasps - The most beneficial wasps come from the ichneumonid, chalcid and braconid families. These control aphids, some caterpillars and whiteflies.
Syrphid Flies - These insects will lay eggs in aphid colonies and the larvae consumes the aphids. Syrphid Flies look remarkably like yellow jackets and bees.
Dragonflies - These large insects consume gnats, midges and mosquitos.
Ground Beetles - These beetles consume snail and slug eggs, cabbage root maggots, cutworms, some caterpillars and armyworms.
Attracting Beneficial Insects
Planting these plants around your garden can attract and feed beneficial insects:
- Common tansy
- Lemon-scented marigold
- White clover
- Evening Primrose
- Pussy Willows
- Sweet Alyssum
Due to the fact that our backyard borders a wooded area, it is not unusual to see deer, squirrels, raccoons, foxes, chipmunks, rabbits, mice and moles. The most destructive of this group is also the cutest, the rabbits, who feed freely on pea and bean seedlings and tulips in our garden.
If the rabbits are attacking the crops in one of our beds, the easiest and most effective barrier has been to wrap the bed in 2.5′ chicken wire. We put a 3’ post at each corner of the bed, and wrap chicken wire around the raised bed box, connecting the chicken wire to the tops of the poles with plastic ties and stapling the wire fencing to the base of the bed.
We have also found it necessary to cover our strawberry plants with Bird Netting to prevent the disappearance of their fruits. Luckily, our raspberries and blueberry plants have remained relatively undisturbed by the neighborhood birds.
Another effective barrier against pets is simply lightweight floating row covers, which can also be utilized to extend your growing season.
Finally, scents are a safe and effective way to repel pests. These options include:
- Citrus – repels deer
- Garlic – repels deer and rabbits
- Soybean Oil and garlic mix – repels moles and gophers
- Spearmint and Peppermint – repels mice and rats
- Dried Blood, cloves, white pepper and garlic mix- repels rabbits
- Geranium, cedar, lemongrass, citronella oil and garlic mix – repels mosquitos