Regardless of the region where you live, mulching the soil around tomato plants is beneficial. Tomatoes benefit from a thick layer of pine straw because organic pine straw improves the soil as it decomposes, insulates tomato roots from excessive summer heat, conserves soil moisture and reduces weeds.
Wait to mulch until the soil is at least 60 degrees F. If you mulch too early, you may trap cool soil temperatures around the tomato plants and delay plant development.
Provide a deep watering for the tomato plants or apply the mulch immediately after a heavy rainstorm. This will ensure that the soil is full of moisture.
Lay down 2 or more inches of pine straw around each tomato plant. Do not allow the pine straw to touch the stems of the tomato plants.
Reapply the pine straw throughout the season to keep it at least 2 inches deep.