Horticulture/Tomato

Tomatoes are in many regions among the most popular fruits grown in gardens, because with most varieties freshness is a major factor in the quality of harvested fruit.

Growing Conditions
Tomato plants need acidic (5.0 to 6.0 pH) soil, a balance between the three primary fertilizer nutrients, and thrive in warm weather. Inexpensive ways to naturally increase soil acidity include using pine needles as mulch, and mixing either used coffee grounds or sawdust into the soil. Pine needles (and the soil under pine trees) are very acidic, and though used coffee grounds are not very acidic, they and sawdust cause a chemical change in the soil, lowering its pH. Fresh coffee grounds or a 4:1 solution of water and coffee can be used for a quick, direct boost in acidity. Tomatoes do not need high calcium content in order to produce good fruits.

In temperate climates, tomatoes are generally started from seed indoors, then planted out after the last frost date. Tomatoes are planted deeply in the soil, often burying the plant up to just below its top set of leaves, as it roots freely off the stem. If staked, trellised, or caged (methods of supporting the weight of vining plants, allowing them to devote more energy into growing fruit), tomato plants can be grown much closer together than the three feet usually recommended.

While tomato plants do best with eight or more hours of direct sunlight, they may do better if shaded during noontime sun if the temperature is above ninety degrees. Some gardeners will actually throw fine cloth over the plants around noon on very hot days. Indeterminate plants require at least twenty gallons of soil in order to grow in a container; it's better to use determinate varieties for containers, instead.

In each tomato plant, there are about 2 to 3kg when the tomato plant has finished growing. Tomatoes tend to grow faster and produce more fruit when companion planting. Marigolds repel aphids and grow well with tomatoes, and Basil both repels insects (even mosquitoes) and improves fruit flavor. Other companion plants for tomatoes are asparagus, onion/garlic/chives, nasturtium, rose, and parsley. Tomato plants are themselves good companion plants for chili peppers, helping shade their fruit.

Varieties

 * Beefsteak VFN (a common hybrid resistant to Verticillium, Fusarium, and Nematodes)
 * Big Boy (a very common determinate garden cultivar in the United States)
 * Black Krim (a purple-and-red variety from Crimea)
 * Brandywine (a pink, indeterminate beefsteak type with a considerable number of substrains)
 * Burpee VF (an early attempt at disease resistance in a commercial tomato)
 * Early Girl (an early-maturing indeterminate)
 * Gardener's Delight (a smaller English variety)
 * Jet Star Hybrid ( low acid, big yield, large globe shape fruit)
 * Juliet (a grape tomato developed as a substitute for the rare Santa F1)
 * Marmande (a heavily ridged variety from southern France; similar to a small beefsteak and available commercially in the US as UglyRipe)
 * Moneymaker (an English greenhouse variety)
 * Mortgage Lifter (a popular heirloom beefsteak known for gigantic fruit)
 * Patio (bred specifically for container gardens)
 * Roma VF (a plum tomato common in supermarkets)
 * Rutgers (an heirloom commercial variety)
 * San Marzano (a plum tomato popular in Italy)
 * Santa F1 (a closely guarded Chinese grape tomato cultivar popular in the USA and parts of southeast Asia)
 * Sweet 100 (a very prolific, indeterminate cherry tomato)
 * Yellow Pear (a yellow, pear-shaped heirloom variety)

Early Spring
Tomatoes grow best in a deep, rich soil, so preparing the bed for this is key.

Seeds are usually planted indoors 4-8 weeks before the last frost date.

Trellising or cages should be put in before the tomatoes are planted.

Summer
Consistent irrigation is key, because inconsistent irrigation can lead to cracking. Irrigation should be to the soil, rather than using sprinklers.

Fall Cleanup
Just before the first frost, it's a good idea to pick the last green tomatoes (which can be used in many recipes, and can be pickled much like cucumbers), as they can be damaged by cold. All vines should be removed from the field (roots and all) to help manage any disease organisms. Seeds will sprout in cold compost piles, so heat composting should be used if possible. be sure to make clean as possible.

Propagation
Tomatoes are almost always propagated by seed but some success has been had with stem cuttings.

Grafting
Tube grafting should be carried out when the seedlings have two to four true leaves and the stems are 1.5 to 2 millimeters in diameter (Figure 3). For proper healing to take place, the vascular tissue in the rootstock and scion must align so that their tissues can easily grow together, forming a strong union for water and nutrient uptake. Again, an essential component for grafting success is to use rootstock and scion plants that have similar stem diameters. Grafting should take place when there is little water stress upon the plants. Early in the morning or just after dark are excellent times to graft as transpiration has typically slowed to reduced levels. Additionally, the grafting process should be carried out indoors or under some sort of shading device. If daytime grafting is essential due to timing and labor concerns, move the plants to a shady area in the morning before transpiration increases to prevent unwanted water stress during the process.

Harvesting
Tomatoes should be harvested as soon as ripe. Most varieties will continue to ripen once picked.

Many varieties have delicate fruits, and should not be stacked too high in the basket.

Pests and Diseases
Tomato cultivars vary widely in their resistance to disease. Modern hybrids focus on improving disease resistance over the heirloom plants. One common tomato disease is tobacco mosaic virus. Various forms of mildew and blight are also common tomato afflictions, which is why tomato varieties are usually marked with letters like VFN, which refers to disease resistance to verticillium wilt, fusarium fungus, and nematodes.

Some common tomato pests are cutworms, tomato hornworms, aphids, cabbage loopers, whiteflies, tomato fruitworms, flea beetles, and Colorado potato beetles and moth lava.

Transplanted tomatoes may begin to show yellow leaves at the base. According to hothouse tomato pioneer, Dan Busch, "With your leaves turning yellow, the tomato plant needs to be fertilized. The fertilizer that you need to use needs to be well balanced, meaning 20-20-20, and if you do not want to use this kind of fertilizer, use blood meal and fish emulsions. This will give you a good source of nitrogen, then you will need to add phosphorus (rock phosphate or super phosphate). Slow growing plants are a sure sign of low phosphorus. Be sure to read the instructions on the blood meal and fish emulsion because it is easy to over fertilize. The real issue here is the nutrition. The yellowing of the leaves is not uncommon with a new transplant, because any nutrition is gone by the time you take it home. If the plants are weak, this is an indication of low potassium. To get potassium in the soil you can add granite dust or wood ash. Call around to local garden centers to find these items.

Viral diseases

 * Tobacco Mosaic Virus (TMV)

Arthropod Pests
To prevent cutworms, tomato seedlings' most vicious predators, one can place an open-ended can so that it surrounds the plant, or wrap it with something like foil or paper, or simply brace its stem with popsicle sticks or toothpicks, all of which seem to deter this moth larva from wrapping around and cutting off the baby plant at its base or leaves.

Vertebrate Pests
Birds occasionally damage fruits by pecking. Chipmunks and rats may eat whole fruits.

White tail deer can be a serious problem in North America.

Yellow leaves on transplants
Transplanted tomatoes may begin to show yellow leaves at the base. According to hothouse tomato pioneer, Dan Busch, "With your leaves turning yellow, the tomato plant needs to be fertilized. The fertilizer that you need to use needs to be well balanced, meaning 20-20-20, and if you do not want to use this kind of fertilizer, use blood meal and fish emulsions. This will give you a good source of nitrogen, then you will need to add phosphorus (rock phosphate or super phosphate). Slow growing plants is a sure sign of low phosphorus. Be sure to read the instructions on the blood meal and fish emulsion because it is easy to over fertilize. The real issue here is the nutrition. The yellowing of the leaves is not uncommon with a new transplant, because any nutrition is gone by the time you take it home. If the plants are weak, this is an indication of low potassium. To get potassium in the soil you can add granite dust or wood ash. Call around to local garden centers to find these items.

Yellowing leaves can also be caused by either magnesium or sulfur deficiency, both of which can be treated by adding dissolved epsom salt or other forms of magnesium sulfate to the soil, and foliar feeding the plant with a mixture of two tablespoons epsom salts per gallon. Foliar treatment is reputed to work within 48 hours, but the soil does also need to be amended as a long-term fix.