How To Grow Heirloom Tomatoes

Wondering how to grow heirloom tomatoes? Fortunately, these delicious vegetable plants are no more difficult to grow than other types of tomatoes.

Heirloom tomatoes are easy to grow. Start with a baby seedling plant of an heirloom variety from the garden center (or grow your own from heirloom seeds at home). Choose a planting location such as a raised bed or a large container and be sure to add a tomato cage or stake. Use lightweight well-draining soil enriched with a slow-release fertilizer. Snip off the bottom leaves and place the plant in a deep hole. Backfill the hole up the sides of the stem and gently pat down the soil. Water deeply after planting and continue watering on a regular basis throughout the growing season.

Read on to get all the details about how to grow heirloom tomatoes!

how to grow heirloom tomatoes

Growing Heirloom Tomatoes: The Basics

Heirloom tomato plants are specific tomato varieties grown from seeds that have been passed down through the generations. These are open-pollinated tomato varieties that tend to be from before about 1950, making most of them over 70 years old. Most are well-known for excellent taste (including the popular Brandywine, Cherokee Purple, Beefsteak, and Mortgage Lifter varieties). These varieties have classic old-fashioned complex tomato flavor and texture when compared to most hybrid tomatoes.

Here are some popular heirloom tomato varieties to grow in your garden:

Read more about different tomato varieties.

Heirloom tomatoes grow very well in raised beds and large containers. They can also be grown straight in the ground outdoors and even indoors using hydroponic gardening systems (such as AeroGarden Heirloom Tomatoes).

Almost all heirloom tomato plants are indeterminate tomatoes (with the exception of a few dwarf types like Tiny Tim Tomatoes). Indeterminate tomato plants tend to grow very long vines that set tomatoes along the vine as they grow. It is not uncommon for vines to grow 6′-10′ long on mature plants. These huge heirloom plants require a proper tomato cage or at least a tomato stake (or 3) if the plants are to produce good yields for harvest.

how to grow heirloom tomatoes

How To Plant Heirloom Tomatoes

Heirloom tomatoes are just as easy to plant as modern hybrid tomato plants. Most beginner gardeners buy baby seedling plants, but you can also grow your own heirloom tomato plants from seeds (see instructions further on in this article). Tomato plants can be planted in a raised garden bed, large pot/container, or straight in the ground.

Always look for a planting location in full sun. These sun-loving plants need at least 6-8 hours of direct sunlight hitting their leaves each day. They can be grown in well-drained sandy loam soil in the ground, but the best place to grow them is in a raised garden bed or another type of large container.

Timing outdoor planting of tomatoes is also important. In cool climates, try not to plant tomatoes outdoors if daily nighttime lows are below 50°F (10°C). These tender plants can be stunted at temperatures below 43°F (6°C). This is usually about 4 weeks after the local last frost date. Read more about when to transplant tomato seedlings outdoors.

Supplies For Planting Heirloom Tomatoes

Step-By Step Instructions

  1. Add tomato fertilizer to the garden soil. Mix the tomato fertilizer into the top ~6″ of soil by following the instructions on the specific fertilizer you’ve chosen. For Dr. Earth Organic Tomato Fertilizer, this means mixing just over a cup of dry fertilizer into every 10-square-foot area of garden space (or 1/2 cup in a 5-gallon planter pot).
  2. Remove the bottom leaves from the heirloom tomato plant. If the seedling only has a few leaves, just snip off the bottom pair. If the seedling is over a foot tall, you can remove 2-3 sets of leaves off the bottom as long as there is a cluster of healthy leaves at the top.
  3. Dig a planting hole. The hole should be deeper than the planter pot, as tomatoes are one of the few plants that can be planted deeper than the soil they come in.
  4. Remove the seedling from its pot and place it in the hole. Check the depth of the hole to make sure that the entire soil root ball is in the hole, plus the portion of the stem that has had leaves removes. Only the top of the stem and the remaining leaves should be aboveground. The leaves should be far enough above the surrounding soil that they don’t touch the ground. Adjust the hole depth if necessary.
  5. Backfill the hole around the plant. Use the soil that was dug out of the hole and gently tamp it down around the root ball and the stem.
  6. Add a thin layer of compost on top of the soil. Top-dress the area around the base of the tomato plant with a 1″-thick layer of compost as a surface mulch. Homemade is best, but storebought fertilizer is also a great option.
  7. Water the heirloom tomato plant. Water very deeply after planting and for several weeks after planting to help the roots become established in the surrounding soil.
how to grow heirloom tomatoes - staking tomato plants

How To Grow & Care For Heirloom Tomatoes

There a few important steps you can take to help heirloom tomatoes grow. Assuming they are in a sunny location, the next important care tip is to water them regularly to provide consistent soil moisture. Heirloom tomato plants grow faster when they have consistent access to water. That said, you can’t grow them in a stagnant puddle. The roots need access to oxygen as well as water, which is why the soil should drain out water easily. Soil should be consistently moist like a wrung-out sponge. This is easiest with automated watering like a drip irrigation system.

Water tomato plants at least every few days, unless the weather is particularly wet. In particularly hot and dry locations, they may need to be watered every other day or even daily. Always water tomato plants right at the base. Avoid getting water on the foliage and instead aim the water at the soil around the bottom of the stem. The best time to water heirloom tomatoes is in the morning so that any water that gets on the leaves can dry out in sun later in the day. Moist tomato foliage tends to become diseased.

As the plant grows, the tomato leaves at the bottom may become yellow or brown. Trim off these leaves as soon as they start to deteriorate and remove them from the garden as they may be diseased. If leaves higher up appear diseased, consider an organic plant spray such as Safer’s 3-in-1 Plant Spray. Heirloom tomato plants do tend to develop diseased leaves sooner than hybrid tomato plants in general. There are also some varieties that have better disease resistance than others (including grafted heirloom tomato transplants).

As the vines get longer, train them in a circular shape around the inside of the tomato cage so the sides can support the larger fruits. If you’re using a tomato stake, tie the plant’s main stem loosely to the stake with a soft tie material at ~1-foot intervals. Heirloom tomato plants in large cages rarely need pruning (unless required for air circulation) but plants grown up a stake will need to be pruned regularly to keep the side shoots under control. This generally means trimming off the suckers that develop where main side shoots meet the vertical main tomato stems.

How To Grow Heirloom Tomatoes

Keep an eye out for garden pests such as aphids, slugs, and even deer. Repellant sprays are usually sufficient to keep pests away (or at least direct them to other plants). Also, take the time to pull out weeds and keep the garden bed free of dead plant debris. You can also re-apply the organic fertilizer at the schedule recommended on the product of your choice (generally every 6-8 weeks during the summer).

Harvest the tomatoes once they have a tiny bit of “give” when squeezed gently. The color should also match the expected ripe color. Classic Brandywine tomatoes tend to be a pink shade. Cherokee Purple tomatoes have a dusky purple color with green patches around the center. Pineapple Tomatoes have vibrant yellow and orange tones.

san marzano heirloom tomatoes

How To Grow Heirloom Tomatoes From Seeds

Heirloom tomato seedling plants are often grown at home because it can be hard to find specific heirloom varieties at the garden center later in the spring. If you have specific varieties in mind and they aren’t offered at local garden centers, it’s time to grow your own heirloom tomato seedlings at home. Most seed companies clearly label the heirloom seeds vs modern hybrids.

Start by ordering heirloom tomato seeds for your desired variety. Many of the best-tasting tomato varieties are heirlooms! You’ll also need seedling potting mix and a seedling tray or small containers. While not strictly necessary, tomato seedlings grow best on a seedling heating mat and while placed under an LED grow light.

Here is a detailed guide to seed starting.

how to grow heirloom tomatoes - cherokee purple tomatoes on the vine

How To Grow Heirloom Tomatoes In A Pot

While small heirloom tomato varieties like Tiny Tim can be grown in 10″-wide flower pots, most heirloom tomatoes require a 5-gallon planter at minimum. Larger 10 or 15-gallon pots or planters are preferable to support the bases of large indeterminate heirloom tomato plants. Whether you’re using a planter pot, grow bag, bucket, or whiskey barrel as your container, ensure that the container has an adequate drainage hole (or holes) to allow excess water to escape.

Keep in mind that the tomato plant will also need a stake, cage, or some other form of trellising. You can even buy kits that include a grow bag planter with an integrated tomato cage, like Gardener’s Supply Tomato Grow Bag Set.

Lastly, heirloom tomatoes in pots don’t have to be planted alone! You can add in some small companion plants for tomatoes like basil, parsley, or cilantro to ward off pests (and make sure you’ve got fresh herbs to accompany your tomatoes to the kitchen!).

How To Grow Heirloom Tomatoes Indoors

The best way to grow heirloom tomatoes indoors is to choose short determinate tomato varieties and grow them in a hydroponic smart garden system. These plants grow all their tomatoes in clusters at the tops of their main stems. Most tomatoes grown indoors are mini cherry tomatoes as these plants mature quickly and have often been bred to be quite compact. Modern hybrids are more commonly grown indoors than heirlooms, but there are a few ways to grow heirlooms indoors.

You can grow heirloom tomatoes in an AeroGarden using their Heirloom Cherry Tomato Seed Kit. In a Click & Grow, you can use the Grow Anything Pods with some Tiny Tim Tomato Seeds. You can also simply grow Tiny Tim (or any other compact dwarf heirloom variety) in a flower pot as long as the plants get adequate light.

heirloom tomatoes

Resources

Mary Jane Duford
Mary Jane Duford

Mary Jane Duford is a gardening expert and founder of Home for the Harvest. She's also an engineer and certified permaculture garden designer. Mary Jane has been featured by publications such as Real Simple, Mother Earth News, Homes & Gardens, Heirloom Gardener, and Family Handyman.