I've got a larger (26') long greenhouse.

Peppers and eggplants have been impossible to grow for me. It's a crappy GH design so it's pretty much impossible to keep humidity inside- so culturally, the spidermites just take over.

Any suggestions for sprays or other methods to stop spidermites from killing everything, besides spraying with water which I've found doesn't work well for mites?

The predatory mites are on my list but the problem is we get very cool nights and it's hard to get them- the window is very narrow for introduction VS too late or too early.

Any thoughts appreciated!