From the Jackson County (Oregon) Master Gardeners:
Some vocabulary to know:
Determinate: Spreads laterally with little or no staking required. Fruits ripen all at once, therefore good for canning.
Indeterminate: Grows vertically, produces until frost, best if staked or caged, fruit ripens until frost therefore good for fresh eating.
Semi-determinate: Semi-determinate tomatoes, especially beefsteak types, have a growth habit between that of indeterminate and determinate types. They produce vigorous lateral shoots that often terminate in a flowering truss (cluster). As a result, lateral shoots are not usually removed.
Parthenocarpic: Means “virgin fruit” flowers will form fruit without fertilization/pollination, tomato examples include: Oregon Spring, Siletz, Legend (able to set fruit earlier giving ripe seedless tomatoes 10-14 days earlier than other types)
Hardening off: Putting a plant outside for increasing amounts of time and sun exposure each day to get it accustomed to being out of the sheltered greenhouse. Start with a half hour in the shade, gradually working up to all day in full sun.
- Location: Tomatoes do best planted in full sun (at least 6-8 hrs./day of direct sunlight) and not in the same location as plants from the same family such as where tomatoes, peppers, eggplant, tomatillos, potatoes, tobacco; have been planted during the last three years!
- Soil preparation: ESSENTIAL for good production. Adding a generous amount of compost and mixing well into the soil is crucial. DO NOT add additional nitrogen because it encourages leaf growth over root and Flower development; the results will be fewer tomatoes. Add water and let it soak in. Some people like to put a mixture of ¼ cup bone meal, ¼ cup organic tomato-vegetable fertilizer, and 1 tsp. magnesium covered with 2-3″ of soil in the bottom of the hole.
- Transplanting and staking:
- Dig a deep hole, big enough to bury the whole plant except for the top two sets of leaves. Pinch off all but those top two sets of leaves.
- Roots will grow from all the little hairs along the stem, making the plant stronger more stable and the plant can absorb more nutrients. Put the stake in before filling the hole while you can still see the roots. Fill the hole and firm the soil around the roots. In the garden, a tomato cage can be used instead of, or with the stake. These supports are more important for both indeterminate and determinate tomatoes.
- Use a tomato tie to loosely tie the tomato to staking in a figure-8 formation.
- Water well. A good rule-of-thumb is to water when the top 1-inch of soil has dried.
This often averages to about l” of water a week in the heat of summer. Watering early in the day is considered a best practice, as the water won’t evaporate too quickly, and any splashs on the plants will dry off as the day warms. It’s better to soak the roots thoroughly once every several days than it is to water lightly every day, as soaking will encourage deeper root growth.
Note: If your plants are looking slightly wilted late in the heat of the day, that’s not necessarily a sign more water is needed. Check the soil first. However, if they are wilted in the morning, if they don’t have signs of a disease, they are in need of water.
- Mulch to prevent drying and weeds, but keep mulch way from the stem.
- Planting horizontally:
- Soil is warmer at the surface and tomatoes need warm soil, so to take advantage of this, follow the directions above for transplanting except instead of digging a hole, dig a trench about 3″ deep and long enough to hold the tomato plant when laid on its ·side except for the top two sets of leaves. Bury the stem and roots in the trench, within 2-3 days, the top part of the plant that is not buried will become vertical.
- Blossom-end Rot (BER) Is caused by a lack of calcium, but rarely due to a lack of calcium in the soil.
- Usually it’s not that the soil is deficient, but that the plant can’t take up enough calcium. If in · doubt, do a soil test.
- Most common causes-
- Drown and drought watering
- Damaged roots
- Planting tomatoes too early. The optimum soil temperature for planting tomatoes is 70° with nighttime air temperature over 50°. Early varieties of tomatoes are less susceptible.
- Not enough magnesium causing an inability of the plan to take up calcium.
- BER can’t be cured, only prevented.
