View from inside.

There is 2' of metal cloth around the base of the boxes as a pest fence, and the poly is zip tied to the metal cloth, leaving one side completely open for air.

I have two gardens, one in my back yard and one at a community garden. At my home garden I flood irrigate. At the community, I sprinkle over the top. I don't have any more disease issues in one garden than I do on the other. I think the problems come from soil splashing on the tomato leaves rather than the water itself. Under sprinkling, the constant water seems to wash off any splashed soils, which may be why I don't have issues with diseases under sprinkling. My climate may matter too. I live in arid Utah where humidities are low and temps can be high so plants may dry out faster than other areas would.

Kevin

Climate can make a BIG difference Kevin - foliage dries out very quickly for you. Not so for many of us. :)

Suburban - with no cross-draft you need some vent holes in the top for heat to escape as it rises. Stick a thermometer in there and you will be amazed how hot it gets.

Same principle as a greenhouse that requires roof vents.

Dave

I hav wind slits in there. And you can't see it. But the side away from the camera is open on the lower foot. The poly is simply tie wrapped to the top of the metal cloth fence.

The tomato plants look awfully leggy. Is that varietal?
Overhead irrigation was my worst enemy before I switched over to drip. I could overhead irrigate one day and the next day see the disease increase.

With the exception of the far left plant (Grape), and the one to the right of that(Early Girl) they are all Grafted Heirloom varieties. I have pruned off yellowing leaves since this picture, so they are REALLY leggy now, but they have 5 feet to grow and fill in. I wanted to prune early, and keep them trained upwards to see if the close proximity works. (they are only 2-2.5' apart stem to stem.

If they get to bushy, and grow into each other, then next year I will just do six (3 in a row down the middle of the 4'x8' box they're in now) to space them out more. I have hot/sweet peppers and two Eggplants out of the shot in the back of the boxes too.

Can you adjust the spray pattern of your sprinkler head so it doesn't spray in that direction?

Or just cap off the one head. No point in losing the plants just because of one sprinkler head. Treat the problem, not the problems it causes. Especially when treating the created problems only makes them worse.

In addition to the reduced light they are getting leggy due to the trapped heat. Anyone with experience in growing in GH or plastic tunnels can assure you you are going to regret this set-up.

Dave