Rich- Wow, thats an impressive amount of advice. I'm also in PA (just north of Philly)....can I bribe you and your varnish brush to help with a few cold ones
? I do have a large fan (36'') at one end of the greenhouse with vents at the other end. It pulls quite a bit of air through. Like you suggested, I have always heard to varnish early on low humidity mornings. However, the teak seems to be gassing and creating bubbles as the temp rises during the day. Would it make sense to coat after the "heat" of the day, as the wood contracts and less likely to create bubbles?