How to Grow Low-acid Purple Tomatoes

Sow purple tomato seeds indoors five to seven weeks before the last frost date in your area, if planting from seed. If planting from starts, skip this step. To plant from seed, slow seeds 1/4-inch deep in a seed tray, then keep them moist until the seeds germinate. Water the seedlings and fertilize with a balanced fertilizer to promote growth.

Prepare the soil for planting after the last frost date in your region. Turn the soil over with a shovel, removing rocks and weeds. Pull apart clumps with your fingers or break them down with the shovel until you have loose soil.

Dig one hole for each tomato plant. Leave 15 to 24 inches in all directions between plants. Make the hole twice as wide and deep as the root ball.

Remove your tomato start or seedling from its container and place one plant in each prepared hole. Hold the plant steady with one hand, then push soil around the roots. Firm the soil around the plant.

Fertilize your plants at planting time to promote growth. Use 1 tablespoon of nitrogen fertilizer per plant, sprinkling the powder around the base of the plant. Fertilize again three weeks later, and then again three weeks after that, applying the same dose per plant.

Water the tomato plants until the soil becomes saturated. Thereafter, water until saturated whenever the soil feels dry to the touch.

Give each plant a tomato cage or a garden stake, loosely tying the stem to the stake with string.

Harvest tomatoes when they ripen. Use the color, a rich purple, and the time to maturity indicated on your seed packet or plant container, as an indication of when to pick the tomato.