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Growing Open Pollinated / Heirloom Tomatoes in the Home Vegetable Garden

Heirloom tomatoes - St. Clare Heirloom Seeds
By Allan Stoner

Open Pollinated / Heirloom Tomatoes are one of the most popular vegetables grown in home gardens. Open Pollinated / Heirloom Tomatoes grow under a wide variety of conditions with a minimum of effort, and they require relatively little space for a large production. Of tropical American origin, tomatoes do not thrive in very cool weather. They are suited to spring, summer, and autumn culture over most of the North and upper South, and they will grow in winter in the extreme South. Each Open Pollinated / Heirloom tomato plant may be expected to yield 8 to 10 pounds of fruit. The number of tomato plants needed will depend on the size of your family. To spread the Open Pollinated / Heirloom tomato, to harvest over the growing season, stagger planting dates at 2 to 3 week intervals.

Open Pollinated / Heirloom Tomato Varieties

Some Open Pollinated / Heirloom tomato varieties are adapted to only certain areas of the country; others are more widely adapted. Choose a Open Pollinated / Heirloom Tomato variety that is suitable to your part of the country and is resistant to fusarium and verticillium wilts. These diseases are likely to be a problem, and the only practical method of control is to grow resistant varieties.

Planting Site for Open Pollinated / Heirloom Tomato’s

Open Pollinated / Heirloom Tomatoes grow best in fertile, well drained soil, but they will grow in almost any kind of soil. Choose a site that receives direct sun rays all day.

Soil Preparation

The time and method of preparing the soil for planting depend on the type of soil and the location of your garden. In general, a cover crop should be grown in the garden during the winter to add organic matter to the soil. This is especially important with sandy soils’ that contain little organic matter. Spade the cover crop into the soil in early spring well in advance of planting. Heavy clay soils in northern areas benefit from fall tilling and exposure to freezing and thawing during the winter. Also, Open Pollinated / Heirloom vegetable gardens in dry land areas should be tilled in the fall and left rough so that the soil will absorb and retain moisture that falls during the winter. Do not spade or work soil while it is wet unless the work will be followed by severe freezing weather. To test for moisture, squeeze a handful of soil. If it sticks together in a ball and does not readily crumble under slight pressure, it is too wet for working. Take the soil samples at both the surface and a few inches below. Sometimes the surface is dry enough, but the lower layers are too wet for working. Moisture may also be tested by inserting a shovel into the soil. If soil sticks to the shovel, it is usually too wet to work.


Fertilizers applied during soil preparation will help Open Pollinated / Heirloom tomato plants grow rapidly and produce well. The kind and amount of fertilizer you need depend on your locality and the natural fertility of your soil. Generally, a 5-10-5 fertilizer (5 percent nitrogen, 10 percent phosphoric acid, and 5 percent potash) gives good results. Sometimes just manure or a nitrogen fertilizer is needed. Fertilizers that contain small amounts of iron, zinc, manganese, and other minor soil elements are necessary only if your soil is deficient in these elements. Soil composition is best determined by a soil test. Contact your county agricultural agent or State experiment station for information on soil tests.

Fertilizer should be applied either a few days before planting or when the Open Pollinated / Heirloom tomatoes are planted. A good practice is to spade the vegetable garden plot, spread the fertilizer by hand or with a fertilizer distributor, then go over the soil two or three times with a rake to get it in granular condition and to mix in the fertilizer. If the soil is left extremely rough, cultivate it once lightly before fertilizing. Because of the small quantities of fertilizer required for some garden plots, it is easy to apply too much fertilizer. Chemical fertilizers should be weighed before application.


Use lime only when a soil test shows it is needed. Do not apply lime in larger quantities than the test indicates. Most garden soils that are in a high state of fertility do not require additional lime. If needed, however, any of the various forms of lime, such as hydrated and air-slacked lime, may be used; but the unburned, finely ground dolomitic limestone is best. Fifty-six pounds of burned lime or 74 pounds of hydrated lime is equivalent to 100 pounds of ground limestone. Finely ground oyster shells and marl may be used as substitutes for limestone. Sometimes Open Pollinated / Heirloom tomato plants need the calcium provided by lime to help prevent blossom-end rot.

When using lime, spread it after plowing and mix it thoroughly into the topsoil. Although it can be applied in the fall or winter, it is best to apply lime in the spring because some of it may be washed from the soil during winter.

Seeding Open Pollinated / Heirloom Tomato’s Outdoors

In areas with a long growing season, Open Pollinated / Heirloom tomatoes may be seeded directly into the garden. Work the soil into a somewhat granular condition. Sow the seeds in rows 4 to 5 feet apart. Keep the soil moist until the seeds germinate. When the Open Pollinated / Heirloom tomato seedlings have 3 leaves, thin them out so they are spaced about one every 1 to 3 feet.

Seeding Indoors

In the more northern areas, the growing season is likely to be too short for heavy Open Pollinated / Heirloom tomato yields, and it is desirable to increase the length of the growing season by starting Open Pollinated / Heirloom tomato plants indoors. Sow the heirloom tomato seeds 5 to 7 weeks before the plants are to be transplanted into the vegetable garden. The tomato seeds may be planted directly into small pots and growing containers, or you may sow them in flats and later transplant them individually into growing containers. The first method involves less handling of the small tomato plants, and there is less chance for the spread of tobacco mosaic virus. Also, tomato seedlings develop more rapidly because the roots are not disturbed by transplanting.

However, tomato seeding into flats and transplanting into pots is preferred by some gardeners because less space is required initially and weak seedlings can be discarded leaving only the best tomato plants for transplanting. Loam or sandy soil, sand, shredded sphagnum peat moss, vermiculite, and perlite may be used in various combinations to start tomato seedlings.

Some of these combinations are:

  • 1 part compost-1 part sand-2 parts topsoil;
  • 1 peat moss-1 vermiculite;
  • 1 peat moss-2 sand;
  • 1 peat moss-1 perlite or sand-1 soil;
  • 1 compost-1 vermiculite;
  • 1 peat moss-1 vermiculite-1 perlite

Various prepared mixtures for starting seeds are available commercially. To insure good germination of Open Pollinated / Heirloom tomato seed, the soil must be kept moist. Temperatures of 70° to 80° F. are best during the germination period. To help maintain proper temperature and moisture for germinating seeds, cover the flats or pots with panes of glass or sheets of plastic until the tomato seedlings break through the soil surface. After germination, remove the cover and water the soil-but only as often as necessary to keep it moist to the touch.

Seeding Heirloom Tomato’s Into Flats

When seeding Heirloom Tomato’s into flats, place seven to eight seeds per inch in rows and cover the seeds with 1/2 inch of starting mixture. Transplant young Heirloom Tomato seedlings into growing containers as soon as the stems have straightened and the leaves have opened-which is usually 10 to 14 days after sowing the seed. The earlier the Heirloom Tomato seedlings are transplanted, the quicker they recover from the shock of being uprooted. Use 3 or 4 inch clay or peat pots or paper drinking cups with a hole punched in the bottom. When transplanting young Open Pollinated / Heirloom tomato seedlings, hold the plant by one of the leaves; even slight pressure on the steams can cause permanent injury. A rich topsoil with a very light addition of commercial garden fertilizer or one of the artificial soil preparations may be used to grow the Heirloom Tomato transplants. The best temperatures for growing Heirloom Tomato transplants are from 65° to 75° F. during the day and 60° to 65° at night. The young tomato plants should be exposed to as much sunlight as possible. For best results, keep the plants in a hotbed or cold frame. If neither is available, keep them in front of a window with a western or southern exposure.

Seeding Heirloom Tomato’s Into Containers

When seeding in pots or some of the new plant growing containers, fill the pots with starting mixture to within about 1/2 inch from the top of the pot. Plant one to three seeds 1/4 to l/2 inch deep in the center of each pot. After germination, pots with more than one seedling should be thinned to a single plant.

Transplanting Heirloom Tomatoes to the Garden

Plant Open Pollinated / Heirloom tomato seedlings outside when the soil has warmed and there is little threat of frost. If there is danger of frost after the plants are put outside, protect them with paper or plastic coverings, newspapers, or boxes. Remove the covers during the day. Set Open Pollinated / Heirloom tomato plants into the vegetable garden at about the same depth as they were growing indoors. It is not necessary to remove the containers if they are made of peat or paper. However, if clay containers were used, knock the heirloom tomato plants out of the pots before transplanting. After replanting, press the soil firmly around the tomato plant so that a slight depression is formed to hold water. Then pour approximately 1 pint water (to which fertilizer has been added) around each plant to wash the soil down around the roots. Use 2 tablespoons of granular 5-10-5 fertilizer per gallon of water. Distances between Heirloom Tomato plants depend on the variety used and on whether the Heirloom Tomato plants are to be pruned and staked. If Heirloom Tomato plants will be staked, plant them 18 inches apart in rows 3 feet apart. If Heirloom Tomato plants will grow unstaked, plant them 3 feet apart in rows 4 to 5 feet apart.


Watering Open Pollinated / Heirloom Tomatoes need about 1 inch of water per week. If rainfall is deficient, water plants thoroughly once a week. Heavy soaking’s at weekly intervals are better than many light sprinklings. Do not wet the foliage any more than is necessary while watering. More frequent watering may be needed if the soil is sandy.

Fertilizing Open Pollinated / Heirloom Tomato plants benefit from fertilization while growing. When the first Heirloom Tomato fruit is about the size of a half dollar, scatter uniformly around the tomato plant a heaping teaspoon of 5-10-5 fertilizer 8 to 10 inches from the stem. Mix the fertilizer into the top 1 inch of soil and water thoroughly. Repeat once or twice a month. If the soil is very low in fertility, more frequent fertilization may be necessary. Poor foliage color and stunted growth indicate a need for additional fertilizer.

Staking Staking makes it easier to cultivate and harvest Open Pollinated / Heirloom tomatoes, and helps prevent fruit rots. However, staked plants are more subject to losses from blossom-end rot than plants allowed to grow naturally. If you plan to stake your Open Pollinated / Heirloom tomatoes, insert the stakes soon after transplanting heirloom tomato plants to prevent root damage. Use wood stakes that are about 8 feet long and l½ inches wide. Push the stakes into the soil about 2 feet. Tie soft twine or strips of rag tightly around the stake 2 to 3 inches above a leaf stem, then loop the twine loosely around the main stem not far below the base of the leaf stem and tie with a square knot. Or use plant ties, made of tape reinforced with wire, to fasten plants to stakes. Wire fencing, about 6 feet high, may also be used to support a Open Pollinated / Heirloom tomato plant. Form a circle around the plant with the fence.

Pruning Prune Open Pollinated / Heirloom tomatoes once a week. Remove the small shoots that appear at the point where the leaf stem joins the main stem. Do not disturb the fruit buds, which appear just above or below the points where the leaves are attached to the leaf stem. It is best to prune by hand. Grasp the shoot with your thumb and forefinger. Bend the shoot sharply to one side until it snaps; then pull it off in the opposite direction. Reversing the direction is necessary to prevent injury to the leaf axil or the main stem.

Controlling Weeds

Weeds compete with Open Pollinated / Heirloom tomato plants for water, nutrients, and sunlight. Weeds also harbor insects and diseases and may be hosts for nematodes.
Cultivating – The area around Open Pollinated / Heirloom tomatoes should be kept free of weeds. Weeds can be removed by hand or with a hoe or cultivator. Loosen the soil with a hoe or cultivator so water can soak into the soil around the plant and reach the roots.
Mulching – Mulches help keep weeds down. They also reduce water loss from the soil and stabilize soil temperature. Rolls of black polyethylene, paper, and aluminum mulch are available in most garden stores. Straw or leaves may also be used as mulch. When using plastic, paper, or aluminum mulch, treat the soil with a broadcast application of fertilizer before applying the mulch. If you use organic mulch, it should be at least two inches deep on the soil to provide insulation, to hold water, and to control weeds.

Blossom Drop

Home gardeners often find that blossoms drop off prematurely and the heirloom tomato fruit fails to develop. Blossom drop is caused by (1) cold temperatures, (2) hot temperatures, or (3) excessive nitrogen fertilization. Nothing can be done to remedy the situation, and you can only wait for later flowers to produce fruit. Rarely does a heirloom tomato plant continue to drop its flowers.


To get the best flavor and color, harvest Open Pollinated / Heirloom tomatoes after they are fully ripe. If Open Pollinated / Heirloom tomatoes are picked green, they can be ripened at temperatures between 55 and 72° F. Light will increase the color of Open Pollinated / Heirloom tomatoes somewhat, but light is not essential to ripening. When Open Pollinated / Heirloom tomatoes are placed in direct sunlight, the added heat often deteriorates their quality.

Insect Control

Several insect species damage tomatoes. Flea beetles, tomato fruit worms, and horn worms may be controlled with carbaryl; aphids and leaf miners with diazinon; and spider mites with dicofol. The insecticides can be obtained at a garden supply store. Follow the directions and heed all precautions on the label.

Disease Control

Two of the most common Open Pollinated / Heirloom tomato diseases occurring in home vegetable gardens are fusarium and verticillium wilts. They are caused by fungi that live in the soil. Before the development of resistant varieties, gardeners were urged to plant in a different garden plot each year: this is still a good idea. The best control, however, is to grow one of the resistant varieties. Spraying or dusting is ineffective in controlling either of the wilt diseases. Blossom-end rot is the most troublesome fruit rot for the home gardener. It is caused by a calcium deficiency and is aggravated by any kind of drought stress on the plants.

Calcium, in the form of finely ground dolomitic limestone, will help prevent blossom-end rot. It must be applied before Open Pollinated / Heirloom tomatoes are planted. Other fruit rots are caused by fungi. Usually, these fruit rots are not a problem when plants are staked. Most fruit rots can be controlled either by (1) spraying with maneb or zineb fungicides at 10-day intervals, starting when the first cluster of fruit has formed, or (2) mulching with a suitable material such as black plastic. In parts of the country where the heirloom tomato leaves are frequently wet because of rain or dew, leaf spot diseases (such as early blight, late blight, and gray leaf spot) can be destructive. They can be controlled by applying maneb or zineb at intervals of 7 to 10 days. Be careful not to wet the tomato foliage when watering the plants; use a soaker hose on the ground.

Virus diseases can cause a mottled discoloration and distortion of Open Pollinated / Heirloom tomato foliage and sometimes can cause mottling of the fruit. Since tobacco mosaic virus is transmitted by direct contact, wash your hands and tools before touching the plants. Do not smoke while handling the plants. Cucumber mosaic virus is transmitted by aphids that may be harbored in some perennial flowers or in nearby weeds. Cucumber mosaic can be controlled by eradicating perennial weeds like ground cherry, milkweed, catnip, and poke weed, and by spraying the Open Pollinated / Heirloom tomato plants with an insecticide that controls aphids.

Open Pollinated / Heirloom Tomatoes are subject to damage by many species of small microscopic worms called nematodes. Most nematode problems go unnoticed by growers because there are no obvious aboveground symptoms except lower-than expected yields. Root-knot nematodes are generally the most troublesome. Severely infected Open Pollinated / Heirloom tomato plants become yellow, stunted, and wilt easily. Their roots can be galled, pruned, matted, or decayed. The best way to identify a specific nematode problem is to consult a local extension service specialist or nematologist who has the equipment and training needed to identify specific nematodes. This is particularly important in selecting suitable nematode control measures to reduce tomato crop damage or losses. The most reliable way to control nematode problems is to use soil fumigants or nematicides when available. Use nematode-free transplants grown in soils that have been heat sterilized or fumigated. Heirloom Tomato plants infected with nematodes before transplanting will not thrive or give maximum yields. These pests will become established in the soil and may cause increasing problems in future years.

Some cultural practices that can be useful and help reduce the damage caused by certain nematodes are as follows:

  • Use resistant Open Pollinated / Heirloom Tomato Varieties
  • Use crop rotation. Do not plant Open Pollinated / Heirloom tomatoes in the same area year after year. Rotate with crops or other Open Pollinated / Heirloom Vegetables that will not support the nematode species causing the greatest damage. Esthetic trap crops such as marigolds (Tangerine variety) may attract and kill enough of the most important root-knot and some root-lesion nematodes to allow for a succeeding crop or two of Open Pollinated / Heirloom Tomatoes.
  • Mix large amounts (about 1 to 3 percent of the soil weight) of finely ground dry organic matter such as mulches into the top 3 to 6 inches of soil. This has been useful in suppressing these pests biologically.
  • Keep area weed free when growing trap and resistant crops to help keep down undesirable and damaging nematode populations.