How much soil (in depth) does a tomato plant need to grow?

http://www.wikihow.com/Grow-a-Tomato-Plant

Use a pot about 18-24 inches high, about 15-20 inches wide.

Transplant the tomato deeply. Bury about 50 to 75% of the plant (especially for leggy plants, that became skinny in raising them before transplanting). It’s okay to bury some of its lower leaves. New roots will emerge along the buried stem, giving the plant a developmental boost; a new transplant needs to focus on root production.

Tomatoes demand a growing medium rich in organic matter.

Feeding

Plants should only be fed with tomato food when plants are beginning to fruit. It is normal practice to feed with a grow food or balanced feed up to the time of flowering, then switch to a bloom/tomato feed when flowers begin to set fruit.

For watering, two main factors are:

Temperature

Size of plant and amount of leaves

The warmer the day – the more water a plant needs. That’s just common sense, but also, take into account the amount of leaves there are.

A plant with few leaves will need less water than one that has a lot of leaves .

How Deep To Plant Tomatoes

Tomatoes will grow in very shallow soil (including the special tomato grow bags that you can buy which are only 3 inches or so deep).

The key to success is regular water (daily if in a small amount of soil) and regular feeding (possibly daily with very dilute feed, certainly every few days).

As long as the soil always remains moist and the nutrients are regularly replaced with feed, they will grow in almost no soil and this is how many large scale growers do it.

Using the horizontal (trenching) technique will give them additional stability. Tomatoes can grow more roots from the little hairs on the stem, so pluck some of the bottom leaves (don't cover the whole plant) and plant away. The root system isn't incredibly deep, but here in the desert the winds are brutal and you need lots of lateral roots to stabilize the plants.

Tomatoes grow best when the roots have at least 12-inches of soil.

2cgmdf

Always plant tomatoes deep.

All the big box stores sell tomato kits and all you have to do is follow instructions.

at least 12in,,better 16in