At first, weeds seem innocuous enough—just green confetti scattered among flowers and vegetables. In fact, weeds bestow a multitude of gifts: holding and protecting bare soils, providing habitat for beneficial insects, and providing food and medicine. Unfortunately, weeds compete with garden plants for space, water and nutrients. If not kept in check, they can seriously affect your garden’s yield and quality.

The key to preventing weeds from becoming a problem is to remove them before they produce seeds. Every pigweed or galinsoga plant that sets seed in your garden opens the door to thousands of offspring. These seeds can remain dormant for years and then sprout when you hoe or till your garden, bringing them to the surface.

Chemical herbicides pose health risks and damage the environment—and they aren’t even the most effective way to control weeds. Fortunately, there are plenty of easy and safe organic techniques to keep garden invaders in check.

Phase One: Basic Prevention

1. Mulch the garden. Using weed-free mulches is one of the best ways to prevent weed problems. Good options include leaves, straw or grass clippings. You can get fresh grass clippings from herbicide-free lawns—either your own or your neighbors’. Grass clippings contain about 4 percent nitrogen and provide a slow-release fertilizer as they decompose.

Straw, the leftover material after grain has been threshed, makes a good mulch because it contains few weed seeds. Hay (dried grasses) can work well, too, but talk to a reputable supplier and specify that you intend to use it as mulch to be sure it isn’t full of grass seeds.

2. Apply corn gluten. This nontoxic, plant-based herbicide is a byproduct of corn processing that kills germinating seeds and also provides nitrogen to the soil. You can’t use corn gluten with direct-seeded plants because it can kill the seeds, but it’s a good option for transplants. You can buy corn gluten products from garden-supply companies. Be aware that corn gluten may contain genetically modified corn, so look for organic versions.

3. Let your garden go stale. "Stale-bedding" is a good option for direct-seeded plants. You let a garden bed go stale the same way you let bread go stale: Just let it sit there. Then water the bed, and when a crop of weed seedlings emerges, kill them with a flame weeder (see #4) or cultivating hoe, creating the least soil disturbance possible.