How to Care for Tomatoes on the Vine

Stake or trellis unsupported tomato plants to give them better structure and to expose the fruit to sun and air. Use a 5 1/2- to 6-foot stake for each plant, and tie main stems loosely to the supports. Don't tie foliage or fruiting stems as those will break. Fruit that gets better sun and air grows and ripens more quickly.

Maintain consistent watering throughout blooming, fruiting and harvest. Tomato fruits consist of 95 percent water and won't grow without adequate moisture. Irrigate the plants with 2 inches of water every week and lay 2 inches of mulch over the soil to maintain moisture and warmth through the end of the season.

Fertilize at a rate of 3 tbsp. per plant when the fruit first appears, using an 8-8-8, 10-10-10, actual nitrogen or calcium nitrate fertilizer. The fertilizer gives the plants resources to grow and ripen their fruit. Feed the plants every four weeks thereafter to maintain your harvest. Sprinkle the fertilizer onto the ground around the plant's stem and mix it into the soil, then water the plant.

Pick tomatoes when they change color and achieve mature coloration. Leave them to fully ripen on the vine, and harvest in early morning when they're firm and juicy with dew.