Barefoot Gardener, Part 1: Bug Off!February 16, 2020, 11:00 AM HST (Updated September 8, 2020, 10:50 AM)
Would you believe me if I said that using chemical fertilizers and pesticides on your vegetable garden actually increases the likelihood of pests?
In 1950, studies conducted by Leonard Haseman, professor of entomology at the University of Missouri, revealed that insects prefer to feed on weak and diseased plants as opposed to vigorous, healthy specimens. And the first step to healthy plants is healthy soil.
Healthy soil is a living ecosystem that contains beneficial bacteria that help break down plant matter and other solids; microbes in the soil help make nutrients available for plant nourishment. There are also vast numbers of beneficial insects that help build the nutritive value of soil. And of course, there are earthworms. Earthworm castings are some of the best organic fertilizer around, so the more earthworms the merrier.
When chemical pesticides are used, they kill good bugs as well as bad ones. Not only are all insects above ground killed, so are the little subterranean bugs and earthworms. Prolonged use of insecticides eventually creates “dead soil” in the garden. If you’ve ever tried to grow anything on old cane field land without amending the soil first, you know what I’m talking about. Being there is nothing living in the soil to break down nutrients for plant availability, plants become weakened and susceptible to insect attack. Simply put, spraying insecticide on your garden can actually attract pests and disease!
In addition to insecticide, a gardener using such “nuke ‘em” tactics will often use chemical fertilizers. I’ve known of people adding double the recommended amount of fertilizer to “make sure the plants are well fed.” Here’s what happens: If there is too much of one nutrient or another it can cause weaknesses in plants, hinder or accelerate growth, and may also create a favorable environment for pests and diseases. For instance, the right amount of nitrogen for one plant may be too much nitrogen for another. Aphids thrive on plants that are taking up excess nitrogen — bean aphids, cotton aphids, pea aphids and cabbage aphids to name a few. That’s a lot of aphids.
The bottom line is that every plant has different needs, even if slightly. Every part of your garden is different. The soil is different from one spot to the next, so is the light, the air movement and so on. That said, the idea of having a healthy garden through employing a one-size-fits-all blanket of chemical pesticides and fertilizers is completely illogical.
Again, building healthy soil is the first step to a healthy garden. I cannot stress this enough. The addition of humus helps hold moisture in times of drought. Plenty of compost feeds the little critters in the soil, such as earthworms and beneficial bacteria. Well-rotted herbivore and chicken manures are excellent fertilizer, especially so when combined with modest amounts blood meal, bone meal and fish emulsion. Rabbit manure is one of the few manures that can be applied when fresh. In the past, I have kept a bunny hutch in the garden so I could rake the droppings directly onto the vegetable beds.
Other highly effective methods of pest control are companion planting and biological control. Marigolds planted next to root vegetables deter nematodes and their pungent scent repels Mexican bean beetles. Ladybugs eat aphids and other garden pests. Insects that enjoy munching on melons and squash run from nasturtiums. And here’s another kind of family feud: any member of the mint family repels pests from any member of the brassica family (cabbage, broccoli, cauliflower, and so on).
Next week I will go into greater detail about companion planting, biological control, soil building and fertilizing. In part three of this series, I will focus on organically preventing plant fungi and diseases.