Growing Heirloom Tomatos From Seed

How to grow heirloom tomatoes from seed, including sources of seed and how to save seed for next year.

Nothing tastes as good as a fresh ripe tomato straight from the garden, still warm from the sun. However, there are tomatoes and there are tomatoes. Many of the varieties grown today are hybrids, especially developed by plant breeders to have certain specific characteristics, such as early ripening, good keeping ability, large size, special color, low acid content, or seedless-ness. Often flavor is sacrificed along the way.

If your interest in growing tomatoes is to have the very best flavor possible then you should not be overly concerned with the hybrids but should look, instead, to the heirloom varieties that are available from specialized seed sellers. These open-pollinated tomatoes used to be the old standbys and are still the standards by which many judge tomato flavor. Varieties such as Brandywine, Mortgage Lifter, Beefsteak, Green Zebra, Garden Peach, and Black Krim are justly famous for the wonderful tomato flavor they retain. Besides being delicious, the plants tend to be hardy and resistant to many diseases, produce large crops on vigorous indeterminate vines, and allow you the option of saving your own seed for next year.

There are literally dozens of heirloom tomato varieties available for the home gardener to experiment with. They come in all shapes, colors, and sizes, everything from tiny grape-like fruits, to huge pink ones, striped ones, purple and even near-black. By growing a few different ones each year you can decide for yourself which you prefer. If you save your seed each year you will always have some to keep or trade with friends.


If you are very lucky, there will be a nursery in your area that starts heirloom tomatoes and offers the plants for sale in the spring. If this option is not available to you then you will have to plant seed and start your own plants about two months before the last frost date for your part of the country. Seed is increasingly easy to find as the interest in heirloom vegetable and flower varieties is growing among gardeners. Two particularly good sources for heirloom tomato seed are The Cook's Garden, P.O. Box 5010, Hodges, SC 29653 and Territorial Seed Company, P.O. Box 158, Cottage Grove, OR 97424. Both of these companies have been around for many years, only sell top quality seeds and plants, and offer a large selection of heirloom varieties.


First determine when your last frost date is expected then count back six to eight weeks. You will want your plants ready to go into the garden as soon after the last expected frost as possible. Either sow your seed in individual pots full of sterile planting medium or make flats for large numbers of plants.

The seed should be covered by about a quarter inch of moist potting medium. The seed must not be allowed to dry out, so water lightly after planting and cover with plastic or domed covers to keep the moisture in.

Tomato seeds like heat and will germinate better and faster if they are kept at a temperature of 70-90° F. Bottom heat is also appreciated by tomato seeds. You can buy special bottom heaters for starting seeds or you can improvise by setting your newly planted flats or pots on top of the refrigerator or freezer. Remember, light is not essential until the seeds germinate and the sprouts start poking out of the soil. It is perfectly ok to set your flats on top of the refrigerator in a low-light room as long as you move them to bright light as soon as the sprouts show.

Once the first set of true leaves appears it is time to transplant from flats. Prick out individual plants with a popsicle stick or spoon handle and pot into 3-4" individual pots. If you started your plants in 2" pots, they can stay there for another week or so. The young plants should now be put in a cooler place, 60-70° F, but still need full light. The cooler temperature will help prevent legginess in the young plants. Earlier flowering can be encouraged by keeping the young plants at 50-65° F for one week only. However, this can also increase the number of "cat-faced" fruits if you wait until the plants have 4-5 true leaves.

Water carefully when the soil surface dries to the touch but do not allow the plants to wilt. Regular fertilizing with fish emulsion or half-strength liquid fertilizer like Peter's or Miracle Grow should be done every ten days to two weeks.

About a week before you want to set your plants out in the garden they need to be hardened off, to get used to outside conditions. Locate a sheltered southern exposure where they will still get full sun but will not be whipped by the wind. Either cover or bring in at night so they don't get nipped by low night time temperatures. You will notice that your plants will begin to look darker and sturdier after being outside for a few days.


Your garden should be already prepared before you set out the plants. Into each planting hole, work in a handful of rich compost or well-rotted manure. If you have had a problem with blossom end rot in previous years or have very acid soil, it is a good idea to add a handful of bone meal to the planting hole as well. Mix this in well with the soil.

Space your plants about 30 inches apart (determinate types can go closer but most heirlooms are indeterminate) with 36 inches between rows. Put your supports in at the same time. You can allow indeterminate vines to sprawl on the ground, but the fruit will be nicer and more plentiful if the plants are staked or trellised.

Until the weather is settled, it is a good idea to protect the newly-set plants at night with row covers or old sheets. This will also discourage animal damage to the young plants.


There are several methods of training indeterminate tomato vines. Tomato cages are popular, but only the really large ones are suitable for heirloom vines. Plants can be encouraged to grow up a fence with a little help or you can erect sections of wire fencing on both sides of the row, allowing about a foot in between. As the plants grow, they will climb up between the two sections of wire fence and with just a few twist-ties here and there will soon fill out nicely. It will be very easy to pick the ripe tomatoes as they will be up off the ground and protected from slugs and small animals.

Heirloom tomato vines can be expected to keep growing all summer long until killed by frost or disease. You should have green tomatoes on the vines at the end of the growing season. These can be brought indoors before they are spoiled by frost and allowed to ripen in paper bags. Or you can have fried green tomatoes or make green tomato relish.


As you enjoy your heirloom tomatoes during the growing season, be sure to take some time to evaluate each different variety and decide which ones you want to make a part of your annual garden. Only save seed from perfect fruits. It is very easy to collect tomato seed. Select a fully ripe, perfect tomato, and slice open. Remove the jelly-like pulp that contains the seeds and spread out on paper towels. Gently separate the seeds from the pulp and discard the pulp. Allow the seeds to dry for a day or two then store them in a jar or envelope in a cool dry place. Be sure to mark each batch of seeds with the name of the variety. When you plant these seeds next season they will produce the exact type of fruit from which they were removed. Do not be tempted to save the seed of hybrid varieties. These seeds will not produce the same plant from which they were taken, but will resemble one or the other of the parents.

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