Make a third application one month later. Water in the nitrogen if rain is not likely. Cultivating and controlling weeds Many weeds are carriers of diseases that may seriously affect tomato plants when transmitted by insects or man. Weeds also compete for soil moisture and nutrients. Use mulches to avoid a lot of hoeing and hand weeding.
Mulches also reduce moisture evaporation from the soil.
Hay, straw, ground corncobs, peatmoss, grass clippings, landscape fabric or black polyethylene sheeting can be used. Apply organic materials 2 to 4 inches thick to prevent weeds from developing. Herbicides may be beneficial in fairly large plantings of tomatoes. Harvesting Tomato color and flavor are best when daily average temperatures are about 75 degrees. High temperatures soften the fruit and the good red color does not develop.