So here is an update. I did buy beneficial nematodes. First batch was the Steinerneima Feltiae from Amazon (Scanmask is the company). Weeks later I see no difference. I even set up a rubbermaid 18 gallon bin filled with 4-5 inches of compost that was moist and used the remainder of the beneficial nematodes mixed in the compost well and then I introduced several grubs and mealworms expecting them to be dead in 48 hours or so. Weeks later the worms are still alive and so are the grubs, so I am guessing the beneficial nematodes weren't even alive. Before I saw the lack of results from the first batch, I bought 2 other varieties from buglogical.com (Heterohabditis and the Steinernema Carpocapsae). With the 3 different strains of Beneficial Nematodes I was expecting joy but several weeks later I still see no difference. With these 3 varieties I should not still see ant mounds or slugs or the grubs. By the way I ordered 50 million of the last 2 varieties in which they claim 50 million would cover a half acre. The area I treated was less than 1/10 of an acre, heck probably 200 square feet. Using 2 of the 50 million batches is would effectively cover a whole acre and I still don't see results in a small 200 sq foot area which tells me these things weren't alive. I also started 2 other containers with compost and added 2 different strains in each container and added mealworms and grubs and they werent dead within 2 or 3 days and are still alive today over 2 weeks later, again telling me the beneficial nematodes were not alive. So to make a long story short $200 spent and no results. Very disappointed.

Thanks for your wisdom. I just want to clarify a few things. The windows are sandwiched between 2X4s on the top and bottom of each row which are supported all around by 6x6 posts in the 4 corners. They basically 'sit' on the 2x4's. The roof is anchored to the four 6x6 posts, so any weight on the roof should direct to the posts primarily and if there is some load on the low side, there's a 4x4 post horizontally at the bottom of that roof also which is also anchored to the 6x6 posts. If the posts sink unevenly I can see that might crack some windows, but hopefully the 4x4 takes the brunt of that weight to the 6x6 posts evenly over time and any sinking happens in unison. The floor has nothing to do with it.. which leads me into the next point... The decking (floor) is totally independent from the walls of windows and roof. The deck is on it's own concreted 6x6 supports. This way if the deck sinks, it has no bearing on the rest of the structure. Think of the deck as it's own island inside a shell that surrounds it. If the deck sinks and the shell doesn't that's ok. If the shell sinks and the deck sinks that's ok too. If they both sink that's also ok. It's only an issue if the shell doesn't sink evenly all around where I might have window trouble. Time will tell on this. We will see how the floor holds up. I did the same thing with no waterproof canvas over it in the old greenhouse (tent one). It lasted 2 years before the floor got funky and that was with no waterproof cover. Basically am experimenting here. I had the underlayment from ripping up carpet in the house. a free insulator, so figured I'd give it another try, but with the canvas over it to see what that's like. :) I do appreciate your expertise, but you may not have been aware of my design choices and my thought process behind them. Hope it makes sense and I get some good years out of the design. It will certainly be better than that plastic tent greenhouse that this is replacing (2 seasons).

Hello azee_2009, OK I originally thought it was going to be a rooftop greenhouse, but after rereading your second post I wasn't sure anymore. As far as the construction I used to build mine, it could be applied to a rooftop situation. By just building a sturdy base for the electrical conduit posts/poles. Similar to the baseboards I made for mine. The weight of it will keep it in place. The poles for my greenhouse only go down in the ground about 8-10 inches, and there is no cement holding them down (just the weight of the greenhouse structure itself). I just posted the link/information to give you some ideas. That greenhouse looks much nicer than the one I built. Although much more expensive too. Not including the subterranean system, and the hydro systems inside, I built my whole 10 by 20 foot greenhouse for about $800. Ya, heat will be challenging. Our outside temp today was about 92 degrees, but the temp inside the greenhouse was 108 degrees. When the temps here reach the 120 mark, greenhouse temps would likely be around 140-150 if I didn't have a multi tiered cooling plan. Cross ventilation is great in some circumstances, but it wont help much at all to blow 120 degree air on your plants when it gets hot. Given the best circumstances, swamp coolers may bring the temps down about 20 degrees. But if humidity isn't carefully controlled, they may only provide a difference of between 5 and 10 degrees at most of cooling effect by themselves. Just to clarify, when I mention high humidity, I mean in the greenhouse. That will depend a lot on temperature inside the greenhouse, water vapor given off from the hydroponic systems inside. Not to mention the biggest factor, how many plants your growing, and how big they are. Plants breath out water vapor (called transpiration). The water vapor (relative humidity) in the greenhouse will get higher and higher unless it's ventilated. But ventilating a cooler greenhouse with the (hot) dry outside air will only heat up the inside of your greenhouse. I have searched the web a lot & every where i have read that Double Poly Sheet that makes air pockets between them retain heat within the greenhouse & reduce heating costs about 50% compared to single poly coverings. So how would i be able to use it. As i have to fight against high temperatures. The air pocket in-bitween the two layers of poly is an insulation pocket. Air pockets are the best insulation there is. Insulation will protect against heat just as easy as it does against cold. If your greenhouse is cooler than it is outside, the insulation (air pocket) will help keep your expensive cool air inside the greenhouse stay cooler longer. If you have no way to cool the inside of the greenhouse, then it wont help much. The air pocket is just insulation, not a cooling or heating layer. It just helps block the heat transfer from one side to the other. Blocks heat from getting out during winter, and blocks against heat from getting in during summer. The 4-5 inch's between both layers you describe should be plenty. Typically it's only about one inch between layers. Though I would expect that you will still get much better results with a air blower between the two layers. The reason is if you blew the cooler air in between the layers, it won't give the air pocket a chance to heat up. Thus keep the heat transfer between the inside, and outside layers to a minimum. I want to know the link & name of software you are using to create 3D images. I want to download it to make someone understand what i mean. I use a free program called Google SketchUp. They have a pro version you can pay for, but I've always used the free version, and like it very much. I save all my drawings into a folder so I can expand on them later without starting over. Before you post your drawings, you'll need to remember to export and save it as a 2D image. Otherwise it wont be in jpg. format, and people that don't have Google Sketchup wont be able to view it. Before I built my greenhouse, I did a lot research online to figure out what would work the best for me, as well as my budget. Here are a bunch of the links I have got bookmarked from those searches. I know it's a lot to read over, and it's been a long time sense I looked through it myself. But a lot of it is in lists of topics. I just read through what was of interest to me. Arched Greenhouse PRESENTATIONS REFERENCE SOURCES Horticultural Engineering Greenhouse Energy Cost Reduction Strategies POLYTHENE GREENHOUSE FILM FACTS Chapter 11- Greenhouse Site Selection Chapter 12- Greenhouse Structures Chapter 13- Greenhouse Control Systems Chapter 14- Greenhouse Energy & Resource Alternatives "Greening" the Greenhouse Greenhouse Glazing Greenhouse Energy Conservation Strategies Greenhouse Energy Conservation Strategies: Temperature and Scheduling Managing Greenhouse Temperature

Structurally it looks like it will work, it doesn't look far different than what I built for my back yard aquaponics set up. I can't see what sort of slope you have on the tubes or if it is adjustable but I found that I had to increase the slope on mine to keep the tubes from clogging from root growth. If your math asks for a 150 liter tank and you think that is too big it should be an easy enough task to recode the arduino to run in two or even three cycles. Isolating the tubes in pairs and running each pair five minutes on and ten minutes off would allow you to cut your tank size down to 50 liters (though 60 would probably be wiser). You would have to add three flow control switches and would probably want to increase the monitoring of the levels in the nutrient tank but I don't think that would be a huge task or expense. You mention that you are using "Underground" PVC.. how does it stand up to UV light? As far as the Arduino goes there have been a few people making noises about building libraries to allow some of the over the counter sensors to measure pH and TDS (total dissolved solids). That will make automation a really viable option.