Spring has returned and now is the time to start planting your warm season vegetables

Part of the fun of gardening is trying new methods like companion planting. In the past, gardening wisdom would just declare that certain vegetables did not get along with other vegetables. There would be no hard research to back up these statements. But, thanks to recent University Extension research all over the country, we now have some strategies for companion planting that are proven to be effective. These strategies can help us reduce or eliminate our use of insecticides in the vegetable patch.

Living mulches are low growing plants that are placed between the rows in your garden to cover the soil

Any mulch-living or otherwise is a good idea, because the mulch acts as a barrier between the soil and the leaves of your crop. Many plant diseases spread when rain or irrigation water splash fungal spores up onto the plant leaves. With living mulches such as clover, you get added benefits like providing habitat for beneficial insects. They can also disrupt the lifecycles of some of our garden pests. Some insects like flea beetles and cucumber beetles lay their eggs in the soil. Others, like hornworms and cabbage worms drop off the plant and go into the soil to pupate. If they cannot reach the bare soil because of the living mulch, then you have made life difficult for them to continue.

Did you know that like us, insects have favorite foods?

You can use this information in your garden to plant trap crops. A trap crop is a sacrificial plant that lures the insects away from the crop you intend to eat yourself and gets them to eat something else. The insect must find the trap to be tastier than the crop you are protecting. Once on the trap crop, you can annihilate the pests with insecticides or just pull them up, trap and all, and deposit them in a plastic bag. Two of my least favorite insects, the squash vine borer and the squash bug, both love blue Hubbard squash. If you plant the blue Hubbards along the perimeter of the garden, they will leave your yellow crooked necks alone. Make sure you plant the trap a couple weeks before the main crop so that it gets a head start.

Radish plants have also been shown to trap flea beetles that love to munch on eggplant. That works for me since I prefer eggplant to radish. Flea beetles are smaller and less mobile than squash bugs, so the radish plants should be interspersed throughout the bed where the eggplants are growing.

Some flowers are very good at attracting beneficial insects that then eat the insect pests for us

Flowers with flat daisy-like faces that bloom in clusters are best for this. Consider zinnia, black-eyed Susans, cosmos, and even herbs left to flower such as dill, fennel, oregano, and lemon balm.

Many beneficial insects pose one problem

After they eat all the pests off your crops, they will fly away to find more food. But, a creative solution to this problem can be found in a banker plant. Banker plants are grown specifically to provide a food source for your beneficial insects. If you have ever grown a milkweed, you know that there is an almost constant supply of orange milkweed aphids that come along with it. When you plant milkweed near your veggies, you can keep those ladybugs around longer and have the added bonus of providing a host plant for the endangered monarch butterfly.

Intercropping is another way to use companion plants by mixing up all the different types of plants in the bed instead of growing things in sections and rows

Insects often rely on chemical cues to find the plants they want to eat. Having the plants and their chemical smells all mixed up makes it harder for the pest to find their preferred meal. There is also the “landings theory”. This theory is that insects will land on a plant and “taste” the plant with receptors in their “feet”. Insects need to land on the right plant a few times in a row before they will then lay an egg. If vegetable plants are all mixed instead of in groups, they are less likely to land on the host plant several times in a row. In a study, researchers noted that 36% of the study insects laid eggs on the host plant grown in bare soil, but only 7% laid eggs on host plants surrounded by companion plants.

Try mixing things up this year-literally

Plant your vegetables in a group with an herb and a flowering plant instead of in sections and rows. Cover the soil to prevent disease and think about using milkweed for more than butterflies.  For more information about Vegetable Gardening in Florida see: https://edis.ifas.ufl.edu/publication/VH021

Article written by Tonya Ashworth, Environmental Horticulture Agent, April 2023

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