1. Don’t Use Mulch Mixed with Soil Mulch, compost, and soil are different things, says Greg Baka, a long-time gardener and the owner of Easy Digging tools. It’s OK to mix compost into your topsoil to improve it, but let mulch lie on the surface. “Mulch mixed with soil damages the nutrient balance, and causes difficulties in digging and weeding,” Baka explains. Jeff Gibson, landscape business manager for Ball Horticultural Company, adds that you should never use woody mulch as a soil amendment in containers or the ground because, “in the process of decaying, it binds up the available nitrogen that could be going to the plants you want to grow....