I'm sure that many gardeners here have grown great tomatoes outdoors. Basically if you follow good gardening practices, have a soil mixture containing both minerals and organics, grow it in full sun, water adequately, and provide some source of nutrients -- whamo! You get a good crop of delicious tomatoes. So if you are happy with your tomatoes I'm not saying you should do anything differently.
The hydroponic situation is not quite that easy because
everything must be provided to the plant. Our knowledge of tomato requirements along with many other vegetables has been extended by studies for production-oriented hydroponics. One very important principle is that it is not enough to have all the nutrients present for optimal performance: they need to be within certain ratios of each other.
Key point: An over- or under-abundance of one ingredient can limit a plant's utilization of another. For optimal crop performance, inorganic and organic compounds need to be present in certain ratios with each other. This is why the formula I'm presenting is a recipe instead of a list of ingredients.
Here are several examples of conflicts among nutrient compounds:
- Excess Aluminum depresses Magnesium, Calcium, Zinc, and Manganese
- Excess Alfalfa Extract over-regulates plant growth unless sufficient Barley extract is present
- Excess Barley Extract depresses Alfalfa Extract
- Excess Cadmium depresses Copper
- Excess Calcium depresses Manganese, Magnesium, and Phosphorus
- Excess Cobalt depresses Iron
- Excess Copper depresses Iron, Zinc, and Phosphorus
- Excess Iron depresses Potassium, Phosphorus, and Copper
- Excess Magnesium depresses Phosphorus and Calcium
- Excess Manganese depresses Iron, Phosphorus, Potassium, and Magnesium
- Excess Phosphorus depresses Zinc, Iron, Calcium, and Magnesium
- Excess Potassium depresses Sodium, Iron, and Manganese
- Excess Sodium depresses Potassium
- Excess Zinc depresses Iron, Copper, Phosphorus, and Cadmium
The first item on this list (effects of Aluminum) is why I am not a fan of Azomite.