1st yes your exhaust needs to be high and your intake vents low. You should also think about an evaporative cooling system if it's over heating.

Yes your HAF fans should circulate air in "race track" pattern. Test with smoke.

Heat will steralize a g/h. But it is going to take more then a couple days. Try 3 to 4 weeks. Just shut everything down, close the doors and walk away. Don't turn on the heater that would just waste fuel. Our highest temp we have reached was 157 degrees. Try walking around in that heat! But you'll also going to kill off all the benifical critters to. Rethink this one.

I would look a university studies for more data.

I think re-arranging our setup might solve most of our heat issues, an evap cooler would be nice but I'm not sure if the recent heat spell was an abberation given how far north we are? (Massachusetts)

Ok, so longer time periods w/ house sealed- so the heat builds up OR to be more thorough in killing everything? We have a pallet burning stove & more pallets than we could possibly burn so I am not so worried about using them if it means a faster sterilization & getting the soil to temp more quickly.

Good / bad critters: we have had beneficials, bees, aphid eating guys, spidex etc, but they are all going to need replacement. My understanding is that the earthworms can dig down into the ground to get away from the heat, our beds sit on earth - but maybe this contact with the ground is at cross-purposes to sterilizing the soil? What other critters should I be worrying about? I thought that growers typically started out with sterile soil, hence no beneficials?

I'll look around for some more data as well, thanks for your thoughts Mylu-

Charlie

"Ok, so longer time periods w/ house sealed- so the heat builds up OR to be more thorough in killing everything?"
Yes and yes...

You stated you wanted to wet the soil first. That would draw your worms up to the surface only to get cooked?

We start with premixed "steril" mix but we grow container stock. You're out of my area of expertise. But I think nature will take care of itself on replacing the benificials.

Still don't think running the heater would have much effect other then maybe at night.

What really needs to happen is for you to ID the issue you have now so you know what direction to take.

I'm not sure I have ever seen exhaust fans set up in this fashion. Usually they are on the ends. SB

I agree with the others on the fan set up.
Is that pressure treated wood you are using as a walkway?
I would remove it.
Call your local Extension Service about getting a soil test and having someone look at your plants.
After years of trying to grow a garden we found out our land was a neighborhood dumping ground. Thank goodness we never got any corn and and very little okra and tomatoes.
We finally moved to another spot and used raised beds and bagged soil. We waited 10 years or so and tried the original spot with new top soil. We got a few squash, a handful of okra. I now grow tomatoes in pots or in my flower beds which had at least 2-3 ft of soil scraped off for a swimming pool and bagged soil put down for my flowers and plants. It seemed in was only in the spot where we found old tin cans, broken china and various car parts that was contaminated.

Mylu-
"You stated you wanted to wet the soil first. That would draw your worms up to the surface only to get cooked?"
Certainly don't want to cook the worms, I was reading up on solar sterilization & they wrote "Solarization is effective only if done in wet soil. The field must therefore be irrigated until a depth of 50 to 60 cm is at field capacity before mulching." http://agri3.huji.ac.il/~katan/applic1.html
I assumed this was to spread the heat through the soil & would therefore be adaptable to the closed greenhouse thermal sterilization we are considering. Do you think worms would head south again when it got too hot?

'We start with premixed "steril" mix but we grow container stock. You're out of my area of expertise. But I think nature will take care of itself on replacing the benificials.'
Good news, maybe a good amount of natural fertalizer each bed.

'Still don't think running the heater would have much effect other then maybe at night.'
We'll try it at night & let you know, sun during the day.

'What really needs to happen is for you to ID the issue you have now so you know what direction to take. '
Agreed. We sampled before when our plant disease problem first occured but the plants didn't test positive for anything, another tissue sample is at Cornell now. Since we have the downtime, we want to get the greenhouse in shape.

SB- I haven't come across a fan setup like it either, just looking online but still, it just doesn't make sense. I think it was a case of the farmer we bought the house from had tomatoes growning with that setup so don't mess with what works? Another explanation I heard was to reduce the cooling the plants experience in the winter, our latitude heat is definitely the minor problem (USUALLY) compared to cold - since the outside air must be pulled in / mixed with the warm air at the top of the house, the plants don't get chilled?

cactus- great point about the planks, I'll go out & check if they are PT right after this. Very interesting about your garden. Could you tell if the car parts had been dumped with fluids inside etc? Tin cans & china should be fairly benign, but maybe high lead levels in the china? In the car parts - they used to use lead for collision repair. Shudder. FYI our tomatoes appeared & tasted great until the very rapid disease onset, I don't think there is a dump underneath as most of the soil in the house area was turned prior to it installation.

Charlie

Hey Charlie,
You said you bought the house from a farmer. Have you ever replaced the soil or is in the same as what he had?

In a field you should always rotate your crops but in a g/h environment you would have to move the g/h or rotate the soli. Growing the same crop in the same place every year will deplete micro-nutriants the toms need and not be replaced. Maybe it's just time to replace the soil?

Planks aren't PT, but we are putting them outside in the sun for a few weeks to disinfect anything that might be living in the wood.

Mylu- Nope, the soil was replaced, we make soil & compost on the farm. I hear you on the micros, but our soil test levels are always fine, we keep it energized with compost. On another note, I ran the #s for our air volume & the it looks like our current fans aren't big enough anyway to replace our house with air every minute - have you had exp with this? The figure I read suggested replacing the whole volume ( or more, up to 1 1/2 ) every minute in the summer - or is this a very zone dependent figure?

Also, I am posting a follow-up on my other post, got some results back from testing, link below is to post.

Charlie

Here is a link that might be useful: tomato problem post

The air exchange every minute is a guideline which, as far as I know of, is not zone dependent. SB

Charlie If we didn't have so many toms now I'd ask you to send some..Anyone want some home made salsa!

Let us know how it goes.

LOL salsa indeed, I used to work the kitchen at this great restaurant, every fall the chef would make an enormous batch of salsa in the steam-kettles for canning.

Mylu, any pointers to posts dealing with restocking beneficials in the house after we sterilize or ideas/posts that discuss 'preventative setup'?

Charlie