Healthy soil is living soil, full of bacteria, fungi, nematodes, worms, and other critters that help make nutrients and water available to plants and fight off diseases and pests. Chemical pesticides and fertilizers can harm those critters and upset the balance of life in the soil that is critical to the health of the plants growing in it. 

Chemicals used to kill insect pests, weeds, and fungus in the garden can kill or injure other living things, including the beneficial critters living in the soil.  

Glyphosate, the world’s most widely used herbicide, has been shown to interfere with worm reproduction. Fungicides have also been shown to harm worms in the soil. Plus, fungicides don’t just wipe out the fungi that make plants sick – they also hurt the beneficial fungi that live in the root zone and help plants access nutrients and water.

Chemical fertilizer can upset the balance of bacteria and fungi in the soil. Normally, plants help out their microbe partners by feeding carbohydrates to these tiny critters living in the soil. But plants that are receiving artificial fertilizer don’t need as many nutrients from their underground friends, so they share fewer carbohydrates in return. This starves the microbes, leaving plants in trouble when they need help accessing water or special minerals that aren’t found in fertilizer.

You can have a healthy garden without chemical pesticides and fertilizers. It all starts with building healthy soil.

• Mulch, cover crops, and different types of plants mixed together in the garden are three effective ways to shade out and smother weeds. These techniques substantially reduce the need to pull or clip weeds, and eliminate the need for herbicides.
• Compost will add nutrients for plants in a garden or yard. A diverse mix of living plants growing in the soil will feed the microbes, which will in turn feed the plants. Legumes like peas, beans, and clover will pull nitrogen – a crucial nutrient – from the air and put it in the soil in a form plants can use.
• Rotate annual veggies to a new spot in the garden every year, to keep pests and disease from gaining a foothold.
• Healthier soil and healthier plants will be more resistant to insect pests, and a host of natural products and strategies are available to help reduce pest pressure. Row covers, garlic spray, or soap spray can deter insects, and a baking soda and water mixture can address fungus on plants while being mild enough to not harm beneficial fungi in the root zone. 
• Provide habitat for helpful insects such as ladybugs and praying mantises by planting colorful, fragrant plants like marigold and yarrow and herbs like dill, caraway, and fennel. These predatory bugs will eat the insects that eat your plants, keeping pest populations down to a level plants can tolerate.

Learn more about building soil health in your backyard