Organic gardening is gaining in popularity at a rapid pace. The most frequently asked question by organic gardeners is how to control common garden pests without the use of chemicals.

One of the most basic methods of pest control is to maintain healthy plants. Through the process of evolution, plants have developed the means to ward off damage from pests.

Healthy plants put out smells that tell the pests to stay away. While weak plants may not yet be infested with pests, they are more susceptible and should therefore be removed. Do not overfeed plants. Too much nitrogen causes tender growth, which is attractive to pests, particularly aphids.

It is important to distinguish beneficial insects from pests. Most wasps are beneficial. They destroy leaf-eating caterpillars. You can attract wasps by planting Queen Anne’s lace, sweet alyssum, yarrow, sunflowers, cosmos, celery and parsley.

Ladybugs are also beneficial, they prey on aphids, mites and whiteflies. Any plant in the daisy family will attract ladybugs. Also, like the wasps, ladybugs are attracted to Queen Anne’s lace and yarrow. Bees, lacewings, praying mantis and spiders are beneficial as they also prey on harmful pests.

Insecticidal soap sprays are very effective for many pests, including mites, aphids and mealy bugs. As with most sprays, type and quantity are important.

There are many insecticidal soap sprays on the market. Check the label carefully to make sure chemicals have not been added. The best insecticidal soap is homemade. Simply mix 1-2 tablespoons of soap with a quart of water. The soap needs to be pure liquid soap.

Dr. Bonner’s Pure-Castile soaps are a good choice. Do not use any type of detergent. Simply mix the soap and water and pour into a spray bottle. Be careful to spray only the problem area. Spraying large areas could result in many beneficial insects being destroyed.

There also many horticultural oil sprays on the market. These oils are highly refined petroleum oils combined with an emulsifying agent. Plant derived oils are also used. The oils are safe and effective and have limited impact on beneficial insects. The disadvantage of horticultural oils is possible to damage to plants. Follow instructions for application of the product carefully and avoid overuse.

Just as certain plants attract beneficial insects, other plants can deter pests. The odor of chrysanthemum, garlic and onions will keep some pests away. Planting basil near tomatoes is also helpful. Aphids are known to avoid the strong smells of chives, basil, catnip, yarrow and mint.

Beneficial insects do their best work in a garden free of pesticides. By planting the right plants and occasionally using insecticidal soaps and oils, you can have a healthy and productive garden without the use of chemical pesticides.

 

Karen O’Neal is an Adams County Master Gardener.

 

May Garden Calendar

Planting

Plant crape myrtles when plants are in color.

Plant annuals and perennials early in the month, keep well watered.

Set out chrysanthemums.

Continue planting gladiolus. Can also plant calla lilies, ginger lilies, tuberose and cannas.

Take hydrangea cuttings and let root in coarse sand.

In the shade plant: impatiens, coleus, sweet alyssum, lobelia and annual dianthus.

In the full sun plant: verbena, periwinkle, ageratum, marigolds, zinnas, petunias, wax begonia, clematis, four-o’clocks and portulaca.

Vegetables that should be planted this month: cucumbers, tomato, pepper, squash, peas, beans, eggplant, corn, okra, parsley, watermelons and cantalope.

Pest Control

Keep an eye on garden pests and diseases: red spiders, thrips, aphids, lacebugs, lacewings, mealy bugs, caterpillars, slugs, snails, mildew, fungus and crown rot.

Pruning

This is the last month to prune azaleas and camellias as new buds are formed in June.

Gardenias can be pruned by bringing a bouquet inside to beautify the house.

Cutting bouquets regularly will keep your plants pruned and prolong the blooming season. Cut in early morning or late afternoon and put into water immediately.

Remove seedpods from bulbs and irises, they sap the plants strength.

Mulch

Mulch layer helps maintain moisture, and can protect roots from extremes in temperature.

Miscellaneous

Water deeply during weeks that it does not rain.

Home Accent

Repot house plants during their active growing period: April through September.

May is a good month to repot and divide overcrowded ferns.

In Bloom

Confederate jasmine, gardenias, begonias, impatiens, salvia, geraniums, roses, H

hydrangeas, magnolias, azaleas, clematis, phlox, sweet william, deutzia, honeysuckle, golden-rain tree, pomegranate, mock orange and weigela.

Master Gardener Calendar provided by Mississippi State University Extension Service