First off are you using a tomato plant that will fit into that tight of a space? some container plants would work . I plant Red robins at 4 per square foot and they grow and produce well. Red robins are only about a foot tall when mature so no problem there. Planting a full size garden tomato in that spacing? Well some tomatoes would take up the whole space by themselves. Now if you are using a compact tomato that will fit the spacing,light should not be a problem, as long as the south facing plants are open to the light. That being said It looks like something I would stay away from myself. It just feels to cramped and reminds me of a few of my failed attempts.

Curt

Thanks for following up, I figure the more responses the easier it will be to help me make a decision. Well I was thinking I would be actually giving them a bit more space since the square foot gardening method suggests 1 plant per square foot and I would be giving them 18". I will be staking and caging them and making sure that they stay pretty tight to their spaces. I was mainly just concerned about light, since I know tomatoes love sun. I would do it in a row if I could but my community gardening plot is only 8ft x 8ft. =(

1 indeterminate tomato per square will work if you prune the suckers and leave one main stem. But because they are so close together, diseases spread easily from one tomato to the next. I do not know if it will work in a block though because of light. But pruning suckers should help.

I wouldn't try to grow 6 plants in that amount of space. You'll have a mess on your hands. You could get away with 4 but only if they are staked and if it were me I'd use determinate varieties. Tomato plants get really bushy and if you crowd them the chances for disease increases and their production declines drastically. The one per square foot rule only applies if you constantly prune out all suckers. And as for your concern about light, if you give each plant adequate space, planting in a block shouldn't cause a light problem. We plant everything else in blocks and never have light issues unless they're overcrowded.

Rodney