How to Grow Tomatoes Organically
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Tomatoes are a tropical fruit, native to South America. Because of this, they must have direct sun for a minimum of 6 hours and should only be planted outside after the danger of frost is past and the soil has warmed up to at least 55-60 degrees. Use a soil thermometer to test the temperature of the soil before planting. 70-degree soil temperatures are ideal for the best growth. You can “pre-heat” your soil by laying down black plastic a few weeks before planting, removing it the day that you plant.
Tomatoes must be started indoors 6-8 weeks ahead of the time you plant them in the garden. In CT, this is around March 15-April 15th.
The pH of the soil should be between 5.8 and 7. Always test your soil before starting a vegetable garden so you understand what you are dealing with. Tomatoes need good drainage. If you soil is poorly drained, consider raised beds or growing your tomatoes in Smart Pots or other large containers.
Tomatoes should not have an excessive amount of nitrogen or there will be too much leaf growth at the expense of flowers and fruit. You want a soil that is high in organic phosphorus and potassium.
It is very important to rotate your crops. Tomatoes are susceptible to diseases. For that reason, don’t plant tomatoes in the same place year after year. Avoid planting tomatoes where potatoes, peppers, or eggplants (members of the same family) grew the year before.
There are two types of tomatoes:
Determinate tomatoes are bush varieties. They do not need lots of pruning or elaborate staking although basic staking is required for ease of harvest. The fruit ripens within a concentrated time period. Many of them are early producers and they are the best choice for containers.
Indeterminate tomatoes are true vines. They must be staked, trellised, or caged. They should also have many of their suckers removed and pruned to an open shape for best disease control. The tomatoes ripen over an extended period of time.
Choose many different tomato varieties to extend your harvest season and offer you a diversity of colors, shapes, and flavors. Some of the most popular types are heirlooms, slicers, cherry, grape, and plum (paste) tomatoes. Tomatoes can be red, yellow, orange, green, purple, and striped. Expand your tomato horizons and try something new every year.
Before planting time, harden off your tomatoes by gradually getting them used to outdoor air and sun. Place in partial shade for a few days and slowly move to full sun over the course of 5-7 days. A cold frame is an excellent tool for this.
When planting your tomatoes, remove a few sets of the lower leaves and bury the plant deep, just past the stem area where you removed the lower leaves. Roots will form all along the buried stems, making them much sturdier and more efficient at taking up water and nutrients. Soak your tomato seedlings in liquid seaweed (Stress X) before planting to further encourage feeder roots.
Amend the soil with Coast of Maine Lobster Compost and Pro Gro or Sustane granular organic fertilizer. If the soil is heavy, lighten it with coir, shredded coconut fiber.
When you have finished planting, mulch with Mainely Mulch shredded straw. Weed Barrier biodegradable paper beneath the straw adds to the effectiveness of the mulch layer. Stake immediately and/or set a very sturdy cage around your plants. Water deeply.
*Tip: Invest in our heavy duty, collapsible tomato cages. They will last a lifetime and will make training your tomatoes so much easier.
Water deeply once a week if we do not have a deep, soaking rain. Water at the base of the plants and do not get water on the foliage, especially in the evening. Drip irrigation is the preferred method if you will be using an automatic watering system.
*Tip: Water deeply, less often, for the strongest, most productive plants.
Feed your plants every two weeks with Neptune’s Harvest Tomato and Veg Formula alternating with Sustane 4-6-4 Granular organic fertilizer. You can also side dress your plants after 4-6 weeks with the same organic granular fertilizer mixed with compost. Occasionally deep soaking or foliar feeding your tomatoes with liquid seaweed (Stress X) will help them to withstand stress.
As your tomato plants grow, remove many of the suckers and prune them to maintain an open shape. This will allow air to flow through the plants, reduce diseases, and result in larger tomatoes. Always remove the lower leaves of your tomato plants as fungus spores splash up from the soil.
Fungus is very common on tomatoes in CT. We recommend Monterey Complete Disease Control (especially if the weather is warm, extremely humid, or very rainy for an extended period of time) to prevent fungus from starting. Spray before you see an issue, or when spots first appear.
Watch for spots on the leaves. Tomatoes are susceptible to Septoria leaf spot, early blight, and late blight. If you see spots, put on rubber gloves, remove the leaves, and discard them in the garbage. If the spots continue, use Copper Fungicide spray to control the fungus, always following label directions.
Blossom End Rot is a problem caused by environmental conditions. The blossom end of the tomato fruits turn brown. This happens if the soil is deficient in calcium (ALWAYS take a soil test!) or if there are long periods of wet weather followed by a sudden dry spell. Thickly mulching your plants helps keep the soil moisture levels more even.
In an effort to provide horticultural information, these educational documents are written by Nancy DuBrule-Clemente and are the property of Natureworks Horticultural Services, LLC. You are granted permission to print/photocopy this educational information free of charge as long as you clearly show that these are Natureworks documents.