I live in northern Indiana Z5 It is hard to see in the picture but on the right side of the box with the toggle switches is a dual contact thermostat and it controls two electric heaters. Next to the left is a thermostat that is set two degrees cooler and it is connected to the heat lamps. Next one is for the ceiling fan. Next one to the left is the Exhaust fan. The small thing in the left end reads temp and humidity. The toggle switches control on off of the grow lights and heat mats and things in the little GH in the corner. The grow lights are on a timer but it is wired through a switch so that it can not turn on the lights if I don't want them on because the switch must be on for them to work. That way I don't need to reset the timer if I turn them off for any reason. One switch starts a pump and I have a small hose with a wand and a push button on the end and my wife just pushes the button to start the flow and it pumps water from rain barrels for watering the plants. Everything can be set for total automation if we are going to be gone for the day.

I used 10' lengths from Home Depot. I didn't flatten the ends, I just bolted it in. At the corners near the rear wall I used 90 degree bends (sold at home depot) with EMT connectors. This gave me a solid U shaped reinforcement. For the overhead cross braces, I did flatten the ends and bolt them to the existing EMT. I used long 6mm bolts from Fastenal for all of the attachment. They slide into the grooves of the vertical T braces. A hacksaw goes through it really quick. You don't need any special cutter. Just get a blade for cutting metal.

It was fun. It's built solid thanks to Gardenerwantabe, Laserfan and the others who were generous enough to help out with ideas on reinforcing it. I guess you're never really done. I ordered shade cloth, misting system and exhaust fan system yesterday. Have to still run electrical out to it too. I'm also working on a variant of a bench I saw that Home Depot uses to display it's tropical/indoor plants.

Hi Mark, congratulations! The vents on my 10x12 are my least favorite part of the greenhouse. I do have them all working, but they seem quite flimsy and the fit is rather fussy. They are noisy in wind. I do have a larger gap on the corner of the vent closest to the overlap of the roof crown pieces (parts 10 and 11) as you mentioned, although it seems to open and close OK. I am impressed you built it by yourself. It would have been very, very difficult for me to get this up without the good help of my husband. Those of you who go it alone get a tip of the hat from me. I ended up following oraylawsons idea about using an adhesive to attach the bottom door rail frame to the base frame. That worked out well. Boy, I totally missed this tip! Wish I had thought of that, I really don't like how loosely the bottom door frame slides and moves on the base frame. Our greenhouse is hot too. With the doors open and all vents open, my greenhouse is at least 120 lately (that's as high as my cheap thermometer goes, I suspect it's higher.) Ventilation and cooling are next on the list of challenges. I will keep my fingers crossed for you on the high winds issue (and crossed for us too.) With all the good modifications given on this site, I'm pretty confident things will go well. One of my concerns is what will happen when we get a big gust of wind when I have the doors and vents open for cooling. I can batten down the house and secure the doors for oncoming storms, but our random sudden wind gusts here are kind of uncharted territory. I hope you will keep us posted on how things go for you! Sheri