Protect your flower and vegetable gardens from pests and diseases with organic insecticides and pesticides. Learn how to control garden pests organically so you protect the environment while you make sure you get the best harvest.

By Paul Krantz
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No garden is totally free of pests and diseases. Fungal infections, caterpillars, beetles, dogs, deer—the list of potential predators seems endless. But you can minimize their damage by using organic pest control.

What is organic pest control? It is a method of protecting your garden against disease and predators without synthetic chemical products. In some cases, you can get rid of problems before they arise by simply switching to organic gardening.

These basic organic gardening tips will help protect against the most common crises that arise in both vegetable and flower gardens.

Beneficial Insects vs. Garden Pests

Not all crawling and flying critters are bad for your garden. Without bees, broccoli, squash, apples and many other food crops would fail; many other insects perform a service by destroying harmful insects. Ladybugs, for instance, can help control aphids. Spraying organic pesticides and insecticides can destroy good bugs as well as bad so should be used as a last resort, particularly when bees are present.

The following are beneficial insects. Don't kill them if you see these in your garden.

  • Ladybugs
  • Praying mantis
  • Hoverfly
  • Lacewings
  • Honeybee
  • Dragonfly

Garden Pests to Pick

Most other insects are pests and can be safely eliminated. But to be safe, learn to ID pests.

Trying to identify a particular pest? The best place to start is the host plant. Insects typically target specific plants, so research what pests your host plant is prone to and whether the pest will cause significant damage.

Some common garden pests to watch out for:

Luckily these bugs tend to be large enough to see and grab. Deal with these larger insect pests and harmful caterpillars by simply hand-picking them off the plant. This approach is easy, effective, and free. If you don’t want to touch the bugs, you can always wear gloves.

Waste Management

Removing dead leaves, fallen fruit, and other debris that provides refuge for pests will help prevent infestations. Also, remove and throw away infested plants; don't add them to your compost pile.

Organic Insecticide and Organic Pesticides

Some gardeners use a homemade insecticide, such as salt spray, mineral oil, or garlic spray. These natural insecticides fight off pests without harming you or the plant. Just remember to reapply these natural garden pesticides frequently, especially in rainy climates.

DIY Organic Pest Control

Many plants are susceptible to attack only while young and tender. Those young leaves are much tastier than older leaves.  The best way to deter pests is by a physical barrier to stop unwanted pests from getting into your garden in the first place. Here are some good options.

Fences

Dogs, rabbits, and other animals may be deterred by installing a fence securely attached at ground level. Larger garden pests, such as deer, may require tall fencing, which can get expensive. To avoid investing a lot in barriers, consider surrounding these plants with individual collars of fencing.

Row Covers

These lightweight fabric sheets drape over hoops or posts to cover plants without smothering them and allow light to pass through. Commonly used in commercial nurseries to protect tender plants from light frosts, row covers also protect vegetable crops from small animals and insects, such as birds, rabbits, squirrels, and caterpillars. Protect row crops with a tunnel-shape cloche created with wire hoops and row-cover fabric.  

Row covers are most useful when plants are young and small, remove them as the plant grows and stems thicken, then turn to natural garden sprays, such as organic pesticides.

Cloches

Sometimes you need to protect only one plant or row of plants. A cloche is a temporary cover sized and shaped to fit a particular plant. For single plants, make inexpensive cloches by cutting the bottom off of gallon plastic milk jugs and setting them over the plants. The primary danger with cloches is heat buildup on sunny days. Make sure to remove or vent the cloches so they don’t overheat your plants.

Cutworm Collars

Cutworms are night-crawling pests that chew through stems at ground level; they are particularly fond of young transplants of broccoli, cauliflower, and their relatives. Foil cutworms and other pests by forming 2- to 3-inch-diameter collars out of large index cards with the ends stapled together. Slip a collar over each transplant and push the collar an inch or so into the soil.

Netting

Sold as bird netting, this lightweight mesh protects berries and tree fruits from birds and pests like squirrels. Physical barriers are generally effective, but there are other options to keep pests away.

Natural Insecticide

Some gardeners make homemade organic pest control insecticide for plants. These recipes rely on ingredients such as salt, mineral oil, or garlic. Use these natural remedies to fight off pests without causing harm to you or the plant. Just remember to reapply these natural garden pesticides frequently, especially in rainy climates.

Disease-Resistant Planting

Various diseases and fungus infections can destroy a wide range of your precious garden plants. Leaves with a powdery appearance or strange coloration are common signs of infection. The key to beating diseases is prevention, mainly by choosing disease-resistant plants. If you aren't so lucky with this option, try these tips to make sure your plants thrive through nasty conditions.

Give Plants Space

Fungal infections need moisture to grow and spread. Crowded plants don't dry as quickly after a watering or rain, giving the fungus the opportunity to develop and spread. Don't space plants closer than recommended, and give them more than the recommended amount of space in humid climates.

Keep Leaves Dry

Avoid overhead watering and overapplying natural garden pesticides, such as organic pest spray. Instead, water around the base of plants when possible. If you are growing vine crops, like tomatoes and cucumbers, support the plants on trellises so leaves and crops don’t touch damp soil.

Rotate Crops

Some disease-causing organisms will overwinter and multiply in the soil beneath a susceptible plant. Vegetable gardens are particularly at risk for this problem. To keep such diseases in check, change where you grow a particular crop each year. For instance, if you grew tomatoes in the northeast corner this year, plant them in the northwest corner next year. Rotation of crops helps promote better soil fertility and is one of the best pest preventions.

Test and Maintain Your Soil

Some plants grown in poor soil or soil that is too acidic or alkaline will develop problems. Your local county extension service can inexpensively test your garden soil and recommend changes to fix deficiencies. Plan to add organic matter to your soil regularly to improve its structure and water-holding ability.

Peter Krumhardt

Keep Weeds at Bay

Weeds are inevitable. Although you can't rid your garden of them completely, frequent light weeding is easier than waiting until the weeds mature and set seeds.

Use Mulch

Mulch has many benefits, including keeping weeds down, cooling the soil, and preventing moisture evaporation. Organic mulches also feed the soil as they break down.

Apply a Pre-Emergent Control

Look for a corn-base organic pesticide that prevents annual weeds from developing. Because these organic pest control products don't affect established plants, they can be applied before seeds have sprouted to control many common weeds. Bear in mind, however, preemergent products don't work on perennial weeds and annual weeds that are up already up and growing.

Repellents

Some organic pesticides discourage insects from munching on a plant. An example would be cayenne, liquid soap, or organic spray mixtures using mint, onion, or garlic. Though effective, these spray mixtures have to be applied every couple of weeks or after a rain. There are also repellants available at your local garden center.

Comments (1)

Anonymous
June 15, 2018
For diseased plants, do not put them in the compost pile. Put them into the garbage can. Elaine Rhodes, Master Gardener