MATHEMATICS OF THE GARDEN: HOW MANY TOMATOES TO PLANT?

One of the main reasons why I garden is to fill my pantry with canned fruits and vegetables that are free of bpa and pesticides. Of all the different things I preserve, tomatoes are by far the most used garden ingredient in my house; it seems like I'm constantly pulling a pot of some kind of tomato product or another out of the pantry.

In the past, I planted 40 tomato plants in one season and have always had a lot for myself and a lot to share, but this year I'm doing gardening in a new location and in a much smaller space. Here in this small lot where the sun is scarce, there is no room for unnecessary excess of plants. I need to know - approximately - how many tomato plants will produce enough fruit to fill my cabinets.

I know the yields will depend on the tomato variety, as well as the climate and my overall success, but this tomato preservation page says:

A bushel of fresh tomato weighs 53 kilos and produces about 18 liters of canned tomatoes or 15 to 18 liters of juice. Approximately 2 1/2 to 3 1/2 pounds of fresh tomatoes makes 1 liter of canned tomatoes.

Past experiences in a hot summer region lead me to believe that a single tomato plant can yield up to 20-30 pounds per season. Since I am doing gardening in a new region for myself and famous for being difficult to grow tomatoes, I suppose I can get between 10 and 15 kilos of tomatoes from each plant. This is nothing more than a hunch, but we have to start somewhere, right?

In one year, my family of four (including two teenagers) will eat:

26 liters of pizza sauce
24 liters of marinara sauce
36 rooms of salsa (I use salsa in chili recipes and Mexican dishes besides serving with chips)
There are 86 liters of tomatoes (more or less, because there will be other ingredients mixed with tomatoes).

In order to stock my pantry with the tomato products we eat regularly, I will need 258 pounds of tomatoes. That means I'll need 17 to 25 tomatoes to meet my family's needs for a year.

I do not have room for many tomato plants, but I've been told that with the mild climate here in Hawaii, I can get two or three harvests a year. Which raises the question: if I can grow so many tomato crops in one season, giving me access to fresh fruit, do I really need to preserve so much?

For now, I have a dozen plants on the floor. Now if only time cooperate!