Spread a 2-to-4-inch layer of organic mulch, such as grass clippings, around the base of the snap pea plants. This creates a barrier to weeds while keeping the roots cool and soil moist.
Clip any weeds that emerge through the mulch with garden clippers. Snap peas have shallow roots, and pulling the weeds may disrupt the root system or dislodge the plants completely.
Add mulch as the original layer settles to maintain an even layer. Grass clippings or other organic mulch breaks down over the course of the summer and needs replacing but provide the added benefit of returning nutrients to the soil.