Roma tomatoes are cooking tomatoes; their meaty fruit cooks down into sauces well, making them suitable for canning as well. Roma tomatoes produce oval fruit that is slightly smaller than many of the salad tomato varieties. They can be planted from seed indoors and transplanted outside once all spring frost danger has passed. They are also readily available as transplants at nurseries and garden centers if you prefer not to start them from seed.
Fill individual seed-starting pots with a quality potting mix. Sow two Roma seeds per pot a quarter-inch deep. Water the soil until moist, then place the pots in a warm room to germinate.
Move the pots to a sunny windowsill once sprouts appear, approximately seven days after planting for most Roma varieties. Water as needed to keep the soil moist but not soggy.
Thin the pots down to the strongest seedling once the plants develop their third set of leaves. Cut off the weaker plant at the soil level and leave the stronger plant in the pot.
Harden-off the Roma seedlings after all danger of frost has passed in spring. Place them on a sheltered porch for two hours the first day, then bring them inside. Set them out each day for a week, gradually increasing the time outdoors each day, in order to harden-off the plants so they are adjusted to outside conditions.
Prepare a garden bed that receives full sun. Lay a 3-inch layer of compost over the bed and apply 2 pounds of 10-10-10 fertilizer to every 100 square feet of bed. Till the compost and fertilizer into the top 10 inches of soil.
Plant the Roma tomatoes 1 inch deeper in the bed than they were at in their pots. Remove any leaves on the stem that will be beneath soil level. Space plants 18 to 24 inches apart in rows that are 4 feet apart.
Water the tomatoes immediately after planting. Continue to water once a week, providing approximately 2 inches of water at each irrigation.
Install a stake behind each plant, or place a tomato cage over the tomato plant, as Roma is a vine tomato and must be supported. If you are staking the plant, tie the main stem to the stake loosely with plant ties every 6 to 8 inches. For cages, pull the fruit-laden branches through the cage opening as you harvest.
Fertilize Roma tomatoes when they begin setting fruit with 1 pound of 33-0-0 analysis fertilizer per every 100-foot row. Work the fertilizer into the soil 6 inches away from the plant stems. Fertilize again two weeks after harvesting the first tomatoes at the same rate.