eastpenna, Good question. Like most things I guess me review of the wire shelves would be "mixed". The good - wire shelving is stable (when properly supported), allows a decent amount of sunlight to pass through to lower shelves, works well for watering (overflow), and it does look very nice. The not so good - wire shelving can be a problem if you use lots of small cups (I often use the little, 3 to 7 oz, dixie type cups) for germination and seedlings. If they are not set in a near perfect position, they tend to tip over with the slightest of touch or when then they get hit with the watering stream. This problem, however, might also be true for the 2x2 system you are looking at as an alternative. The only way around it that I can see is to use solid board shelves, which will cut off light and be a problem with watering overflow. Or you could not use the small cups on these racks. In my case, I use the small cups and just learn to keep my swearing well muffled whenever they get tipped over. Maybe some other folks have come up with better options.

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. :-)

Hi poaky1, I definately, absolutely needed extra clips for my HF 10x12 greenhouse, as well as screws through the panels into the frame. I can positively state that my greenhouse would not be standing today if I had not taken these steps. I did not caulk my panels in place, because I like to be able to remove them if needed. So, my solution was extra clips and screws, but Saturn3600 (above) used both extra clips and caulk, on his or her 6x8 greenhouse. There used to be more frequent threads around here, years ago, about Harbor Freight disasters, back before people knew to take a few extra steps to make the panels and foundation more secure. Here's one, for example. Greenhouse Disaster HFGH 10x12 You're the only one who can decide if it's worth the extra $9.99 plus shipping, for a package of 72 clips. To me, a little extra insurance seems like a no-brainer. Even if I lived in a climate that did not have uniformly high winds, I would not want to risk the loss of my greenhouse, or plants, but that's just me. An unusual gust of wind or errant windstorm can happen anywhere, even if it's not the norm. You can order extra clips by calling the 1-800 number on your Harbor Freight manual. For the 6x8 greenhouse, Harbor Freight uses the part number 46 for the panel clips. The SKU number is SKU number 27339, for a set of 72 clips, $9.99. Hope this helps, I know some of these decisions can be confusing. I sleep better if I err on the side of stability and safety (I really hate surprises.) I think they usually ship the clips pretty quickly.

Yes, I have read of people bolting them down. How do you do that with out harming the panels? It doesn’t harm the soft polycarbonate panels to put a screw through them. You could drill a small pilot hole and insert a screw, or use the self-drilling screws we used. We only used one screw per panel, roughly in the center of the panel. Man the panels are like cardboard and will be amazed if they hold heat... Normal winter temps are in the 30's sometimes cooler. Twinwall polycarbonate is much more efficient at holding in heat than a single layer of glass or fiberglass. Our lowest winter temps are usually in the low teens, in a normal year. You can check out the different heat loss values for different covering materials, at the calculator I link to below. I plan to run a heater and add a 60 gal water barrel. Most people find that trying to use stored water to retain heat through a cold night doesn’t work very well, especially in a small greenhouse where space is already at a minimum. You might search the archives for more opinions on this topic. I use two 1500 watt heaters in my 10 x 12 greenhouse, zone 8. The link below is to a greenhouse heat calculator you can play with, to figure out the amount of heat you’ll need, based on greenhouse covering, size, minimum outdoor temperatures, etc. When you use this calculator, remember the HF twinwall polycarbonate is 4mm thick. greenhouse heat calculator Should I use washers too? Sure, wouldn’t hurt. Washers will help prevent the bolt heads from biting down into the surface of the wood, as you tighten them down. If you haven't done anything like drilling into concrete before, you might want to find a neighbor or buddy who can give you a hand with it. Weather stripping is a good idea,but even with my smaller model that can be pricey. Where as the screws and silicone or caulk might be cheaper? I bought my weatherstripping on eBay from a surplus seller, for a much lower price than our local box stores. It was too wide; I just cut it lengthwise with scissors. So from your blog I can expect there to be gaps for water leaking in and heat escaping. Not quite sure what you mean; I had a few gaps at the tops of the corner posts, as I explain in the blog, and fixed those with clear caulk. I don't have water leaking in. I also post in the blog that I haven’t regretted the time or money for the weatherstripping, since I think it helps prevent heat loss. I can’t measure how much of a difference it makes, truthfully, since I haven’t built a HF greenhouse without using weatherstripping. Not sure exactly on the aluminum tape at the ends? You said to tape it to seal it then you put holes in it for air exchange which I understand. But if you put holes for air exchange then what purpose is the tape doing? I’ve currently switched to using clear duct tape (Lowes) on my panel ends; it seems to last longer in our high heat. The aluminum tape worked fine, but peeled off after about two years of our brutal sun. Here’s a thread that explains more about this: thread discussing sealing polycarbonate panel ends The above thread also has some information about how to order extra Harbor Freight panel clips, if you decide to.