What are the Best Techniques for Growing Heirloom Tomatoes?

Jennifer Voight

When growing heirloom tomatoes, it’s important to start the seeds indoors about six to eight weeks before the last frost date in a sterilized seed-starting medium. A fluorescent grow light on a timer placed no more than 6 inches (15 cm) from the heirloom tomato plant will ensure that the seedlings get 12 to 14 hours of light each day. Once the tomatoes have produced two sets of true leaves, the outdoor soil has warmed, and the last frost date has passed, the heirloom tomato seedlings are ready to be hardened by sitting outside in the shade for about a week or two. After hardening, the heirloom tomato plant should be planted in a small trench with the plant lying on its side and buried up to the first set of leaves so it will develop a strong root system along this stem and produce a hardier plant. Heirloom tomatoes should be watered very consistently, about every two to three days.

Crostini with heirloom tomatoes, mozzarella cheese, and basil.
Crostini with heirloom tomatoes, mozzarella cheese, and basil.

Growing heirloom tomatoes are more susceptible to the cold than other varieties. The hardening process will help them toughen so they can endure the stress of changing weather patterns, wind, and extremes with less damage. About a week or two before planting, tomato plant seedlings should be placed in a shady part of the garden in an area protected by the wind for about 30 minutes. This can be increased each day by about an hour until they are out overnight on a night when there is no danger of frost. The plants can gradually be exposed to more wind and watered more frequently as they are exposed to sunlight.

Yellow heirloom tomatoes.
Yellow heirloom tomatoes.

Growing heirloom tomatoes in containers is similar to growing heirloom tomatoes outdoors. The bottom third of a 15-gallon (about 57-liter) container should be filled with compost. The heirloom tomato plant should be set deeply into the container and buried up to the first set of leaves. All buried leaves should be pinched off before burying so the plant doesn’t direct nutrients to them. Heirloom tomatoes planted in a garden can be transplanted in a similar way, buried up to the first set of leaves.

To prevent blossom end rot and cracked fruit, heirloom tomatoes should be watered consistently. Watering should be done only when the soil has dried out an inch or two beneath the surface. Too little water will result in less fruit, while too much watering may result in cracked and split fruit. When growing heirloom tomatoes, inconsistent watering will result in blossom end rot. Heirloom tomato plants should be mulched with grass clippings or commercial mulch. Tomato plants may be fertilized with a balanced fertilizer when planting and once after the first small fruit appear.

Grass clippings may be used as mulch when growing heirloom tomatoes.
Grass clippings may be used as mulch when growing heirloom tomatoes.

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Discussion Comments


I grow heirloom tomatoes in my garden every year, and I have a tip that helps the plants produce a lot of tomatoes.

Often, young tomato plants will bud and produce small tomatoes before the plant is actually mature enough to sustain them. Though you may not like the idea of removing these early tomatoes, taking them off the young plants until they grow stronger and larger will help them to produce more fruit later in the season. If the plants are very young, early tomatoes will deplete them of nutrients and stunt their growth. This is the reason that removing them will help the tomato plants thrive.


As with any type of tomato plant, heirloom tomato plants should be kept upright to prevent the fruit from lying on the ground. Tomato plants typically have thin stalks that have the tendency to bend and fall over. This is especially likely to happen when the fruit grows and becomes heavy. When this happens, the tomatoes often become discolored, rotted, or eaten by bugs.

Using tomato stakes is the easiest way to keep your tomato plants standing. Simply tie the plants loosely to the stakes as they grow, adding more ties as needed based on growth of the plants, sturdiness of the vines, and size of the fruit.

If you prefer, you can also use tomato cages to keep your plants upright, though you have less control when using them and they are often more costly than tomato stakes.

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