szut, I have built both a wood framed and steel framed GH. First was the wood one. It has survived well but is in need of a repaint and recaulk which was part of the reason I went with steel for the second GH. The other reason was strength. Wood 2x framing is fine for smaller structures. But if you are trying to span longer widths, the size of the wood becomes prohibitive. Especially if you have high snow or wind loads to contend with (I have both). I think you will find Al for structural members is not doable for other than rather small sizes (hobby GHs, etc). Perhaps if you use built up Al girders, but that would be very pricey. Most commercial GHs use steel structures. I ended up going with steel tube arches from a commercial GH, which I made into a lean-to GH on the side of a barn. Given the structural loads it had to meet (50# snow and 135mph wind) it was relatively cheap (no doubt would have been cheaper in less extreme environments). IMO if you can build with wood 2x material, making the transition to steel tubing should not be that hard. You'll need a few new tools (metal saw and drill), but in many ways it was just like working on a big erector set. As a cost saving, you could look into buying a used commercial GH, or at least the frame. That could give you the structural material at a very inexpensive cost. Something that is harder to do with wood 2x material. My steel GH is too new for me to say how it will fair on the maintenance side. But I expect it to handle the moisture better than wood, although it will need some touch up painting no doubt in time.

Inside the greenhouse Sweetlee tangerine tree in ground, 3 hardy chicago fig trees in 5 gallon buckets, and above 2 bell pepper plants in stack of 3 cans 1 gallon each can. A cherry tomato at the very bottom of the picture above. ************************************************************ The other sweetlee tangerine tree in ground at the east end of the greenhouse. ******************************************************************** This is a 30 gallon Meyer lemon and a 5 gallon hardy chicago fig. ********************************************************* This is the other Meyer lemon tree in the greenhouse. The gallon food tins to the right have spinach seeds. There are 23 spinach cans total. ******************************************************** Meyer lemon pollinated. ************************************************** The last picture is my sweetlee in a 30 gallon container. This picture was taken before the west wall had any glass. The video link shows more detail of the inside and plants of the GH Steve Here is a link that might be useful: https://www.youtube.com/watch?v=m8-nVd3r8vw

I'm in the Kalamazoo area. Brad-during the first week of school I build a succulent garden with my students. We talk about how plants are like children. We all come to the classroom with different root systems, and we all have different needs. We talk about what is good for all people and how we all want to be treated. I keep the garden in front of a window all year and the students love watering it and watching it grow. It's a fun activity for building community. I also have a hamster because some children never get to have the opportunity to care for a pet. It always amazes me how kids love taking care of plants. We were just laughing on Friday about how H. Chelsea seems to be growing before our eyes. It's going to be another week of 90+ degrees in Michigan with no air conditioning in our school. My plants will be happy, but my students will be miserable. I keep reminding them to look on the bright side. We aren't in the path of a hurricane. We haven't had an earthquake, and we rarely have tornadoes. Blessings to all our friends who have a lot more than hot days to deal with.

Ok, good to know, I have really taken to the Polish- Ukrainian varieties. Black Krim, Black Prince and just acquired a yellow variety, European origin but cannot think of its name. A friend passed seed on to me. I tried Malinowy another European raspberry tomatoe, extremely high rated tasting tomatoe, needs staking. However all the fruit ending up rotting with blossom end rot. Not going to grow again.