Mulch, Leaves, and Weed Control

Weeds are nature's response to bare soil. Exposed soil is quickly colonized by whatever seeds are present — most of which have been waiting in the soil seed bank for the right conditions. The most effective weed control strategy is to prevent bare soil from existing in the first place.

A layer of mulch on the surface of garden beds does three important things: it blocks light to weed seeds, preventing them from germinating; it retains soil moisture, reducing the need to water; and it moderates soil temperature, protecting plant roots from heat and cold.

Two to three inches of mulch over bed surfaces, applied after planting, significantly reduces weeding labor throughout the season. Top up mulch each year as it breaks down — as it decomposes it also feeds the soil.

Arborist wood chips — the rough, chunky chips produced by tree trimming services — are one of the best mulches available and often free. They break down slowly, provide habitat for beneficial soil organisms, and look natural in garden beds. Many arborists will drop off a load of chips for free rather than pay to dispose of them.

Avoid dyed or processed wood mulches, which offer fewer benefits and may contain treated wood materials.

Fallen leaves are one of the most valuable resources a gardener has, and most people either bag them for disposal or pay to have them removed. Leaves are nature's mulch. Run them over with a lawn mower to shred them, then spread them over garden beds. They break down over the season, feeding the soil and suppressing weeds.

A thick layer of shredded leaves applied in autumn protects beds through winter and improves the soil significantly by the following spring.

When weeds do appear, remove them before they set seed — one weed can produce hundreds or thousands of seeds that remain viable in the soil for years. Pull weeds when the soil is moist, and try to get the full root. Cutting weeds at the surface often leaves a root that regrows.

Avoid tilling or turning the soil to remove weeds. Tillage brings buried weed seeds to the surface where they can germinate, and disrupts the soil biology that supports your plants.