Quote Originally Posted by WashougalWonder
Well, doesn't matter exactly what it is, you have identified positively the problem exists in the grow room.

If plants staying outside get colder....including the roots.....as in they are in pots above ground, then it positively is something airborne. In that case I would empty the grow room and fumigate and spray fungicide big time all over.

Conversely, if the roots outdoors are in the ground and have ground temp to keep the feet warm, then it could be the cold issue, and I have never seen a plant really recover from it if in flower.

So....You are there, just which one is it? Just how cold did that room get? Below 50 degrees? That is the magic number...in S,Cal it got that cold?
The outdoor plants are in pots, above ground.

The temps may have dropped below 50. We had one week that just passed not too long ago where it was beyond cold. I love the cold weather, and usually cruise around with shorts and flip flops on, when everyone else is all bundled up.... but this week, even I couldnt take. It was very cold. So I wouldnt doubt that it dropped below 50 for 2-3 days.

We'd hate to toss out all of our plants and start over, but we may have to. We see that the worst plants are still trying to form new growth at the tops, so we're hoping that we roll out our little plan, that they'll all recover.

We're still in Veg. We have some 3-4 foot tall plants, that are still in Veg. We cant flip the lights to flowering until this has been fixed and we get some good new growth.

The plan as of right now is to install heaters to bring the room up to a constant 85 degrees. Then treat the plants with a Potassium Bicarbonate Fungicide, until we are confident that all of the Neem Oil has been rinsed off the leaves. Then We're going to bring in a Sulfur Burner, and let that burn for 2 nights in a row. Then start spraying the plants down with a 3-in-1 spray that has sulfur in it. We're also going to crank up the CO2 a little.

So we'll see what happens.