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Growing Tomatoes Organically - Soil Preparation

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Growing Tomatoes Organically
Purchasing Seeds
Growing Seeds
Soil Preparation
Early Fruiting
Pest Control
Disease Control
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Soil preparation

Soil preparation is the key to best practice tomato culture. While the tomato bush is a gross feeder, it is also a constant feeder. It respond best to slow availability of just enough nutrient - a major feature of a well developed organic soil. Composted or well-rotted animal manures should be dug into the ground at least six weeks prior to planting - three months would be better. If you have not done this for your early tomatoes, its already too late - use only a well made garden compost immediately prior to planting, to avoid burning plant roots.

Soil fertility

Blood and bone is an ideal fertiliser for tomatoes and can be used safely at planting time, but you will need a potassium source too. A good general purpose organic fertiliser will also do the job. Don™t add too much fertiliser at planting time, it will only produce lush, bushy growth and won™t improve the quantity or quality of the fruit. Side dress additional fertiliser during the growing season.

Organic sources of potassium include composted poultry manure. granite dust and liquid seaweed fertiliser.

Don™t hesitate to use side dressings of potassium fertiliser or blood and bone during the growing season rather than trying to put all the goodies in the soil prior to planting.

Boron deficiency causes black areas on the stem tip, stunted tip growth and very low ˜bushy™ vine shape. Terminal shoots nay curl and die, or fruit may darken and die. use a handful of ordinary borax scratched into the soil around the plants. Most other trace element problems are solved best by compost and liquid seaweed fertiliser.


Transplant the seedlings deeper than they were planted in the pot or nursery bed, If there are five rows of leaves, you can plant up to or above the bottom row. Extra feeding roots will grow from the stem, and the deeper root system will aim drought resistance and hardiness.

Use a sieved compost around the roots and water thoroughly.


Pruned ˜indeterminate™ varieties to one or two leaders, depending on plant vigour, and remove laterals from the leaf axis.

Determinate or shrub varieties don™t require pruning. A low, inclined trellis will keep fruit off the ground.

You don™t need to prune foliage, it protects the vital stem and the fruit from burning or overheating and makes food (ie photosynthesis) for the tomatoes.

Broken or damaged pieces may be safely removed with clean (ie disinfected) secateurs.

Water management

Tomatoes are very sensitive to water management. They should be allowed to wilt a little between waterings and the rule is fewer, deeper irrigations. The best way to apply water will vary greatly between soil types, but flood irrigation once per week is a good guide to aim for (they won™t last this long in very hot weather).

Except for the odd wash-down with the hose to remove summer dust and freshen the leaves, or perhaps a fortnightly application of dilute liquid kelp fertiliser, do not wet the leaves of tomatoes (it encourages fungal diseases).

Keep the soil mulched once it has warmed up. Tomato roots will exploit the environment under the mulch, running over the old soil surface. Deeper roots draw moisture from below.

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