Remove as many weeds as possible from the soil. You can pull live weeds or kill them first with a layer of boric acid powder or white vinegar. Allow the boric acid powder or vinegar to penetrate the weeds for 24 hours before pulling them from the soil.
Cover the soil around the tomato plants with newspaper. The newspaper prevents future weed growth and is biodegradable.
Spread a 2-inch layer of pine needles over the soil. Leave adequate space around the tomato plants to allow for future growth.
Even out the layer of pine needles with a rake. Run a rake over the needles until an aesthetically pleasant, uniform layer is created.
Water the mulch and reapply an additional layer in three to four months. The pine needles degrade over time and require reapplication.