Six Weeding Mistakes In the process of trying to eliminate weeds, people often make mistakes that lead to more weeds. Here are the most common: 1. Leaving weeds that are in flower on the ground. Even after they are pulled, weeds like chickweed and purslane can continue to develop seeds. 2. Piling too much mulch over landscape fabric. As the mulch breaks down, it provides a perfect medium for weed growth from wind-borne seeds. You can actually have weeds rooted to the fabric. Limit mulch depth to 1 or 2 in. over landscape fabric. 3. Applying mulch containing weed seeds. Sometimes mulches such as straw and wood chips contain weed seeds. To avoid this problem, buy from a reputable nursery that offers mulch free of weed seeds. 4. Tossing weeds with seeds into the compost pile. A good compost pile can get hot enough (160°F) to kill weed seeds. But there are often cool spots where the seeds can survive. Those that do will be spread in your garden with the compost. 5. Breaking apart the roots of perennial weeds as you try and dig them out. Each piece can grow into a new plant. 6. Planting weeds along with your new shrubs and trees. Just a few nutsedge or Bermuda grass plants growing in a nursery container can spread and multiply in your garden. Make sure to remove them before planting.