tomatoes planting pattern in a raised garden?

Typically you plant tomatoes 3 feet apart. I've done 3 feet apart and you can put them near the edges to help conserve space. I would do 7x3 because whether it's 4 feet wide or 3 feet wide you'll only be able to fit 2 rows without shading a 3rd row. And if it's up against a wall even 2 rows might have a hard time getting enough light. You can fit 3 plants in each row, planting 6 inches away from the wall on the long side and maybe 3-4 inches on the short side. Set up trellises or metal wire fences on each side for each row. Or put a 4-6 foot tall tomato cage around each tomato plant. Tie vines loosely to trellises or cages with plant ties.

You can get more tomatoes per square foot with pruning and a 1 foot plant spacing, but this is a ton of work. For support you instead set up a strong pole for each tomato plant and tie the plant to the pole. Whenever you see a sprout growing between the main vine and a branch, you pinch it off or else it will become a new vine. And you only want 1 vine on your pole, maybe 2 tops. You have to be super diligent about this, twice a week pinching and tying to the pole. You'll get a higher yield this way but it's a lot more work so I never bother nor do most people. Stick with what I said in the first paragraph IMO and don't prune anything.

Tomatoes need lots of room. How much research have you done into tomatoes? You don't mention what kind they are. That makes a big difference. There are two basic types of plants (I'm not talking about the fruits). There are Determinate or bush tomatoes and there are indeterminate. The latter will sprawl all over the place. Some varieties of indeterminate tomatoes can take up huge amounts of room. There are some determinate plants which have been bred to take up very little space - "patio tomatoes".

The trick to getting plenty of fruit is to have good cages which will support the plants and keep the fruits off the ground. I use welded wire fence cut to form a semicircle around the plant. I will tie particularly heavy branches up with old socks or my wife's old hosiery. I do not prune the plants. The leaves are solar collectors supplying the plant with energy to make more fruit.

I give determinate plants about 18 inches on each side. More is better. Indeterminate plants get at least two feet on each side.

There are all kinds of techniques for growing tomatoes and no two people do it the same. It's really an art.

You can use either. You can also put the plants very close together. Some people plant two or three together in one hole. The pattern is not critical.

What you have to be careful about is having too many plants and then you end up with more tomatoes than you can use.

On raised beds, you need to grow Up, not spread out.

Plant your indeterminate Tomato's up against the wall and use the wall to tie them up, so they go up the wall flat against it. I use cup hook screws for this. The hook screws into the wall and I can hang the tomato plant from the hook using garden ties.

Plant the determinate Tomato's on the other side of the bed, leaving enough room between the plant and the edge of the bed to install a Tomato cage on the raised bed.

gg