How To Control Pests And Disease In Gardens Without Chemicals

Biologically Intensive methods in gardening are practices and systems that use no synthetic chemicals and rely on biological processes that are renewable, non-polluting, and beneficial to soil, plants, and the local ecosystem.

In Michael Pollan‘s book The Omnivore’s Dilemma, he describes his visit to Polyface Farms in the Shenandoah Valley of Virginia. The owner of Polyface, farmer Joel Salatin, uses biologically intensive methods to produce a vast amount of food on one hundred acres of pasture surrounded by forest. Salatin doesn’t refer to himself as an organic farmer – although his methods are certainly that – Joel is part (perhaps something of a leader) of the biologically intensive farming movement. Salatin uses no fertilizers or pesticides, no Agrochemicals of any kind, no antibiotics for his livestock. His cows, chickens and pigs are extraordinarily healthy and free of disease, his chickens’ eggs are loaded with Omega 3’s and in high demand, and his crops are plentiful. In fact, Joel is so good at what he does that he is invited to speak all over the world, teaching his methods to other farmers and to those who are just curious.

In Biologically Intensive Farming, the farmer learns the local ecological connections between his crops, his animals, his pasture, his surrounding forest and the soil that supports them all. It’s farming that ignores Big Ag and relies on knowledge of animal and soil biology, botany and horticulture.

 Buy on Amazon: The Omnivore’s Dilemma: A Natural History of Four Meals 

So how does biologically intensive farming relate to your garden?

For the past 60 years or more, we’ve been fed data on controlling pests and diseases in our garden that benefits the chemical and petroleum industry, not our gardens, not our plants, and not our health. This data – using chemicals derived from petroleum distillates to control insects and fertilize our edibles – is so prevalent in gardening and farming culture that it’s considered heresy by many professional growers and scientists that better pest and disease control (and yields) can be attained without the use of these inputs. As many growers and gardeners have now learned, using chemicals to treat pests and disease triggers a cascade effect: the elimination of one pest results in an infestation of another; using synthetic fertilizer destroys the microelements and organisms that live in the soil near a plant’s roots. When plants and soil can’t survive without chemical intervention, they require more chemical intervention to survive (great business model, isn’t it?).

“Pests and diseases on your farm are nature’s way of telling you that you’re doing something wrong” – Polyface Farms’ Joel Salatin

So back to the garden where we’ll apply the Biological Farming method. Pest control and disease control don’t start when lacewings are discovered in your garden or black spot is discovered in your pear trees. When you create ecological balance in your garden, when your soil is alive with microbes which support your plants, there is rarely any need for inputs aside from compost and water (barring extreme weather events). If your soil is alive, birds will eat their weight in insects every day. If you interplant herbs and flowers with tomatoes, carrots, and peppers, they’ll host friendly insects and deter detrimental insects. If you rotate your crops year to year and plant cover crops, you won’t deplete the soil and invite infestation. Aside from a drastic weather event such as a hurricane, tornado or drought, serious problems rarely develop in the biologically balanced organic garden. When they do, they’re more easily controlled.

How to apply biologically intensive methods in your garden

Test your soil

Before planting anything, inspect your soil. Test its water holding capacity by squeezing a ball size amount in your hand – does it stick together or turn to dust? It should stick together but be easily pulled apart, unlike clay. This shows good soil tilth. Is the soil a deep dark brown color or clay color? If it’s clay you have lots of work to do (see my previous post on soil conditioning in your garden). What kind of life is in your soil? You should see at least a handful of earthworms and other insects crawling around. If insects and worms don’t find your soil appetizing, neither will your plants.

Add compost and humus

If you haven’t already, build a compost pile. Composting is absolutely essential, as it will replace the micronutrients that growing plants remove from the soil. It also supports bacteria and fungi which feed on plant refuse and help turn it into humus. Think of it as vitamins and fiber for your soil.

Add airflow

Make sure that there is good airflow around plants to reduce the chance of fungal infections.  The ability of a plant to dry quickly after a rainstorm is crucial. If the season is particularly humid or wet, this is all the more important.

Invite wildlife

Don’t make your garden off limits to wildlife. Destructive animals like groundhogs, rabbits, and deer should be deterred, as they will sample everything they see. But birds and pollinators like bees are essential to your garden’s health. The more pollinators you attract, the better the blooms.

Use cover crops

Use cover crops in your vegetable garden. Cover crops restore nutrients to the soil which crops pull out.

Use Mulch

One of the most important inputs is mulch. Cover the root zones of every plant with at least 2 inches of mulch to insulate the roots from weather extremes like freezing soil, frost heave, drought, and heatwaves. As the mulch will also hold moisture closer to the root zone, it will make the topsoil more inviting for bacteria, insects, fungi and earthworms which will break down organic matter faster (including the mulch), and create a soil more hospitable to your plants.

For more detailed information on insect and pest management in your garden, see Insect Pest Management from Alabama A&M and Auburn Universities.