Hey very cool bud! We have matching greenhouses! I also modified those plans going 12x16 with a 10 ft center peak and went 4 ft on the side walls instead of 3, also went with an 8ft french door
Because of all the heat I didn’t do any of the metal flashing though, back wall is OSB and the bottom 2 ft on the sides are the radiant barrier osb
Lol nice! And works out well for you also??
Oh ya! Got a swamp cooler on the back of mine for all year round growing
I may have to try a swamp cooler… I need some form of cooling… Not alot, but some.
Swamp cooler in the bottom and a small panel out in the top for the air to escape is the answer! It can be 115 outside and inside is fine
Ice storm left a tree branch in the side of greenhouse. Luckily it is some damn tough plastic and just left minor holes… And in the north side to boot! So feeling pretty lucky…
Sorry to see that. 🫣 Could have been a lot worse though.
Damn, that sucks!
Guess it could have been worse. Glad y’all are ok!
Way to roll with the punches. 
Why the gravel?
I would have sowed straight into the soil with a seed mix of everything, cannabis and companion crops; herbs, vegetables, spices. 
Awesome build. I’ve been thinking about getting a cheap hoop house from eBay or Amazon and fortifying it a bit after deer screwed me over last year
U can build them fairly cheap also.
I’ve built a few for myself, friends, and mother.
I posted the link around here somewhere. Fully customizable. I love mine.
I’ll dig it up and post if you’d like.
IDK about soil next to an old fairgrounds, you’re looking at a lot of years of gas and oil from those cars along with whatever nasty pesticides or heavy metals are left over. Not all soil is good soil, unfortunately. Where I live looks beautiful and green but we’re on top of an old rail yard and coal gas refinery, toxic as heck. We have to do all our vegetables and herbs in raised beds with fill from somewhere cleaner.
Yeah that would be sweet. The eBay/Amazon ones just seem like a decent base to work with. There’s people on YouTube that have modified them a bit to make them more sturdy and been running em for years
Aha… ofcourse. In that case I would cover all soil in woodchips and sawdust inoculated with oyster mushroom spores and mycelium to clean it all up. After a year most of the polution should be broken down into safer compounds.
Feel free to read this book by Paul Stamets - Mycelium Running for more info. 
I do like the work of Paul Stamets and the idea of mycoremediation, but even he says that remediated soil is for landscaping and other non-food crop uses. I wouldn’t grow my weed in anything I wouldn’t grow food in, and to my knowledge that is still not recommended on highly hydrocarbon-contaminated soils even after mycoremediation when there are other options. I am not a subsistence farmer for whom growing food in a remediated field is the difference between starvation and survival, so I’ll opt for the safer choice. Purity on this sort of thing is not really useful, some soils are not good and might never be again. Where I live the persistent residues of industry are everywhere in unpredictable ways from over 250 years of pollution. Much safer to just use soils and amendments in raised beds and keep the ground for ornamentals and flowers IMO. I think the OP made the right choice to utilize the old pad and then gravel the rest, there’s always the option of using those dirt areas for non-weed or food growing, but having a nice controlled environment in the greenhouse is sort of half the reason for it.
Yeah my property is built on “landfill” type soil… I dig down and it’s lots of old pottery… Gravel… Concrete… It used to be where they dumped the excavation material for the main town. It’s very poor soil. We have spent a large amount of time and money fixing the soil where our outdoor vegetable garden is and didn’t really feel like it for this area. Fabric pots work pretty nice as I can move them around for pruning and pest inspection. Plus all the concrete and gravel is a great heatsink for the cooler nights.
You’re right about the pad and gravel being great heat sinks to give your greenhouse a gentler temperature arc over the day and night. It’s definitely worth considering some water tanks in there painted flat black, I have known folks who had great success with passive solar house and greenhouse designs that utilized black water tanks on the south side and dark flagstones or painted concrete pads all to absorb heat from the sun and slowly release it. Stuff like purpose made water walls with pond liner and lumber but also just black painted olive barrels and water barrels. I love high-low tech answers, some people call it appropriate technology but that has also picked up some bad connotations of first-world judgement so I don’t use it as much anymore. Retro-modern folk science stuff, peasant research that turns out to be timeless? I met a guy once who constructed a mass heater in his greenhouse with a small wood pellet rocket stove to power it, that’s my dream there, a greenhouse with a big mass heater hearth inside to pump out heat and some CO2 to vent into the space in winter to make a sealed setup work, but all-natural low-tech sealed.
This is a little old book you might enjoy, it’s easy to find a cheap modern paperback reissue of it that’s sharper probably but here’s a scan of the original from Cornell University Library and the Internet Archive, the PDF is too big to post:
Can always use a bit of greenhouse tape when it warms up as well. Love the setup by the way, the wiggle wire is making the build look extra clean. Do you take the poly off in the summer?
Didn’t even notice that! The pro move, wiggle wire is great and really easy on the cover, especially if you give them a quick wipe with a piece of sandpaper to make sure they’re smooth on the cut ends
I guess planting nitrogen fixing trees is also good idea, providing shadow (you can prune them into the perfect amount of light penetration), and they improve drainage and make minerals bioavailable, if you allow the leaves to decompose where they land.
More trees also attract more birds and beneficial insects eating the ones we don’t want, pollinators, and all of them poop, further improving the soil, etc, etc.
Ripple effect.
Do as you please of course, thou art free! 
