Aluminet is pretty rip resistant but I still don't think grommets will hold if you don't have tape edging sewn on.

thanks. I ordered some of these:
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Will I still need to do tape edging with those? Know where I can find out how to do to that?

I don't know if they will tear out of Aluminet or not. I don't think I will test it on mine. ;-)

It is my experience that those tarp anchors work only fair. You have to bend the barbs to get them to hold the first time, and they pop off occasionally. Worth a try though.

I added 60% Aluminet to the outside of my 10x12 greenhouse roof about two years ago. Like you, I didn't know what would work either, but tried the simplest method first. Instead of using edging tape, I made a simple hem in the Aluminet. I just folded raw edge over twice, by hand, about 1" each fold, and whipped it down by hand using Nylon thread and a large-eye needle.

Then I applied grommets (cheapie kit from Harbor Freight) through the three-thickness section on the edge, every foot or so.

We attached 1x2" wooden strips to the edges of our greenhouse roof (screwing them to the aluminum frame.) Then we added screws sticking up out of the wooden strips, every foot or so. The screws are slightly angled out, so the screw heads will capture each grommet.

Not very fancy, but it has worked great. In the last two years there have been two occasions when a grommet (at the corner) flipped off the screw in very high winds, but that's easily slipped back on. I haven't seen any tearing, (maybe because my grommets go through the folded 3-thickness "hem" I made.)

I also bought the black plastic fasteners you show above...but never used them, since our first attempt has worked out so well.

We've been pretty surprised at how little wind resistance the Aluminet seems to have. It's not uncommon for us to have bad wind gusts in the 40 to 50 mph range, right on the front of my GH (especially this time of year, which makes me quite grumpy, since I have to bolt the doors shut and can't get in there!)
Sheri

Sheri, I was originally planning on doing something like you have done. My greenhouse frame is wood so I was going to skip the wood strips and just put in anchor screws every foot or so and then stretch the shade cloth to fit it on the south wall and the roof. Would you recommend folding the edge twice and sewing, or would you do tape edging if you had to do it again? Also, can I get a simple grommet kit at Lowes you think?

I haven't had any trouble yet with my folded-over, hand-sewn hems with grommets. I haven't had any experience using tape edging, so I truly don't know how much more difficult it would be to apply, or how much stronger it is, in the long run.

Aluminet is funny stuff. Once your order arrives, you'll be able to see how it handles, and it might be easier for you to decide what to do. I just laid it out on an empty floor to measure it, creased the folded edge with my fingers, and pinned it with long straight pins to hold it while I hemmed by hand. Not hard, but it takes a while (no fair cheating and using 6" long stitches!)

We don't recall seeing grommet kits at our local Lowes, but you might check. If you don't have a local Harbor Freight store, both Ace Hardware and Sears list grommet kits online (you could call your local stores to see if they stock them.) They're also for sale on eBay.

Okay my wife and I are going to hem the shade cloth today (we got it in the mail yesterday). I wasn't going to do 6" stitches, but I would like to do 1.5 to 2" stitches. Think that is acceptable?

I'm sorry for the slow reply...I've whip-stitched the hemmed edges using stitches no larger than about 1/2", but that's not to say going larger will definately make a problem. (The smaller stitches fit my fussbudget personality.)

I've used the same technique to hem an Aluminet "sliding curtain" that I use to keep sun and birds out of my GH when I have the double doors open...clipped to the open doorway with small clamps, so it doesn't fly into the GH and snag plants. It has been whipped about by the wind for a few years, with no problems.

Good luck!

Applied the shadecloth to the roof and south wall. Ended up using the hinged grommets sold by gemplers.com. They seemed to hold really tight and grabbed more material than a regular grommet would.
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Good deal! I really do like the Aluminet, and hope you do too.

That looks great, and I doubt you'll have any trouble. You can watch the leading edge of the shadecloth, to see if the wind seems to be catching it anywhere. If so, you could always apply additional hinged grommets. I found I needed to apply additional clips to one side of one particular poly panel of my greenhouse, on the SW corner, since that one spot seemed to always be hammered by our winds. I just watch, and tweak...

Looks great!

Yeah I'll watch it closely in a strong wind. It doesn't seem to have much wind resistance. The thing I'm worried about is whether it will be enough when it gets 95 degrees here. Maybe I'll need 80% shadecloth.

Today it was 74 degrees outside, and at the sun's hottest point, the temperature in the greenhouse advanced the outside temperature by 8 degrees (the spread was 16-18 degrees without the shadecloth). So it is an improvement, but I think I need a more powerful exhaust fan. My greenhouse probably isn't much more than 500 cubic feet. The 6" fan I have now probably doesn't do enough to exchange the air in a minute. So I figure if I put in a fan with a max speed of 1100 cfm, then I can keep it cool as the outside temperature even if it's 95 degrees outside (also using an evaporative cooler). Think that's far fetched with only a 50% shadecloth?

Here is a link that might be useful: my greenhouse blog

Other folks here are a lot more knowledgeable than I am, and can better help you predict what you'll need (my experience is pretty limited.) I used this calculator when deciding which size exhaust fan to buy:
exhaust fan calculator

Cooling is my biggest challenge, as we have a few days over 100°. Even with my GH doors open, exhaust fan running, and most of the south wall panels removed, I can't keep my GH the same as the outside temps. But, I don't have an evaporative cooler like you do.

If necessary, you could add another layer of shadecloth for the hottest parts of the year, and remove it later. You might watch that you don't remove too much light as you work to lower the temps. I have to balance finding the bright light my succulents need, while doing what I can to lower the temps with shadecloth. I think it depends on what you grow.

In case it helps at all, this part of my blog includes a section about choosing and adding our exhaust fan:
Part Seven, Greenhouse Enhancements

Nice! I love the mosaic countertop. My wife likes to do tile mosaics as well. I also noticed you made a shadebox for your thermostat. I haven't done that yet, so my thermostats are sitting on in the sun. Any idea how much that may be skewing the temperature readings?

Thanks, I love my mosaic bench/sink area. Honestly, it's usually got so much dirt and crud on it, it never looks like those photos in my blog anymore. But, it works!

Having the thermostats in full sun will definately skew your readings, but I can't say how much. This is my first greenhouse too, but I read that it's best to locate thermostats close to the center of the greenhouse, close to (or just above) plant level, and out of direct sunlight. Because the thermostats are basically the "brains" of the greenhouse, I figured it was worth a bit of hassle to try to hang them in a good spot. Also, I tend to slop water everywhere, and knew that mine would be safest if they were hanging from the ceiling...but with your slick system, that shouldn't be a problem.

Here are a few threads/links that might give you more ideas:
Thermostat location
thermostat placement in a greenhouse
how to install a greenhouse thermostat

I spent time with your blog this morning, and it's really good (and fun to read.) I love the stone foundation, stoplight lenses, and the row of glass bottles (being a closet fan of funky folk art and bottle houses...)

I think the important thing is to have fun, and it looks to me like you're doing a great job of that. You are right that everything always costs more than we think it will, but I figure at the end of my life, I won't be saying "I wish I hadn't spent money on interesting hobbies that taught me stuff...!!"
Good for you.

We always purchase our Aluminet with seam tape and grommets installed. It always seems to be much more reliable and much less fragile like that. We also do something most people don't do and that is we install it on the INSIDE of our greenhouse. We find it looks better, installs easier, works great and doesn't get all tangled up when we put the solar pool cover ove rthe GH in winter.

Our GH is aluminum so we have channels that we can install a nut/bolt in to hold the aluminet in place. Works great.