Nice job. I am going to build something similar next fall for my tropicals and yours is a great guide. Now - can you do a pictorial on rebuilding the transmission of a 1974 Ford Maverick? LOL.

A recent update from the person who received the yucca is that it is green and doing well. The transplanted cholla are doing well, of course, but it will be a while before I know if any sacaton survived. We have been making progress but not as quickly as we hoped. (No surprise there! ;-) ) We have the foundation blocks for the outside beds in place up to ground level and filled with dirt. Pavers have been placed, but not yet leveled, between the existing shed and the north edge of the foundation. We have the water and electrical stubbed in. We have the SHCS tubes in place for the outside beds of the east greenhouse and hope to start filling that section soon with the removed dirt. We have removed all planned use of poured concrete from our plans and have made this planned structure possible to remove easily while still unlikely to be blown away. (Mostly due to bolting the foundation via J-bolts to rebar under bond beam cement blocks.) DH will be checking to see what type of permits/inspections we will need for electrical, water, and structures. I suspect that it will be just water and electric. We won't fill in any more until we find out. It is getting hot already so we will be putting in the outside structure and shade cloth before the central shed and greenhouses. That way we can work in the shade. :-)

jungle: That might work if you can stand 120-130F in your greenhouse. It will not do better than that. If you want real cooling buy a 36 inch slant wall exhaust fan to go with an appropriate size wet wall. I'm in Alpine TX at 4500ft elevation. My 1725 sqft greenhouse has three 36 inch exhaust fans with 1/4 hp motors and a 4x28ft wet wall. Two of those fans are adequate until it gets above 90-95F then I turn on the third. Last year when we were near 100F many days I could hold mid 90s on the hot, exhaust end. Mount the top of your wet wall and top of the exhaust fan as high as you want cooling. It will not cool higher than that. Mine are mounted at about 7ft and I wish it were 8ft. The upper air in the greenhouse is 120F+. Your exhaust fan needs to achieve one air exchange per minute to hold warming to 10-15F above outside. The wet wall provides air at 15-20F cooler than outside. My electric bill for fans is about $50-70 per month but it is the only way in our climate to keep a greenhouse usablely cool in summer. Run it on 220V if possible for economy and long motor life.

I'm not familiar with the book you describe, but an easy way to secure a piece of plastic sheeting (like visqueen) is to take a small, round object like a marble or a pebble, place it on a corner of the plastic and fold the plastic around it. Tie a cord around the folded plastic so that the object is secured inside, and then tie the other end of the cord to a stake. If you do this correctly, the cord won't slip off the plastic and the stress on the plastic is spread so that there is little risk of tearing. Does that help, or not?