You should put down a weed barrier before sod. A weed barrier is a material, typically plastic or cloth, that is placed on the surface of the ground to prevent weeds from growing. It is important to use a weed barrier because weeds can compete with new sod for water, nutrients, and sunlight. Weeds can also damage new sod by pulling out the grass plants with their roots.

Before installing sod, you should put down a weed barrier. A weed barrier will prevent any weeds from growing up through the sod, and it will also help to conserve moisture. You can buy weed barriers at most hardware stores. They typically come in rolls that you can cut to fit the size of your lawn. Simply lay the weed barrier down on top of the soil, and then place the sod on top of the weed barrier. Be sure to tamp down the sod firmly so that it makes good contact with the soil.