Mulching is known to prevent weed growth and help retain soil moisture. While mulches are often considered organic materials such as bark or rocks such as gravel, plastic mulch is available that offers many benefits compared to traditional mulches. Black plastic is superior at blocking weed-seed germination, it helps warm the soil earlier in spring, and keeps fruits and vegetables cleaner and less prone to disease as they don't sit directly on the ground. Laying plastic mulch requires some minimal soil preparation beforehand.
Fertilize before laying the mulch. Use 4 lb. of a balanced 5-20-20 fertilizer per 100 feet for vegetable beds or a general-purpose fertilizer for flower beds. Work it into the soil with a tiller or a hoe.
Water the bed until it is evenly moist throughout but not soggy. For wet beds after snowmelt in spring, allow them to dry until evenly moist before mulching.
Dig a 3- to 4-inch-deep trench that is 3 inches wide around the bed. Lay the plastic over the bed with the ends in the trench, then backfill the dirt back in the trench, anchoring down the plastic mulch.
Cut a 6-inch hole in the plastic, then sow the seedlings or plants in the center of each hole cut. Use dirt to anchor the plastic down around each hole that is cut for planting.
Water the mulched bed as usual, either placing the hose under the plastic or punching holes in areas with standing water so the moisture drains to the soil beneath.