Help Designing Greenhouse?

I am trying to get together a general game plan for designing a greenhouse for my back yard. I would like to be able to do this all myself, if possible.

Probably important info:

I live in Louisville, Kentucky, where a quick google says we are either zone 6 or right in between zone 6 and 7. I will operate under being in zone 6.

I want to mostly grow leafy greens, maybe with a tomato plant in there as well.

I want to be able to produce year round, maybe not tomatoes, but at least the leafy greens.

I need the greenhouse to be at least somewhat insulated, to produce year round.

The orientation of the green house would have to run east to west longways. Facing the back of my yard is roughly west, the right side is north. It has to be on the far right side of the yard, because that side of the yard is the only part that gets good light, there is some there for most of the day, if not all of the day.

The greenhouse can be about 10 or so feet wide, and long ways much longer, 20, 30 feet even.

I was thinking double layer poly. The structures "bones" I have not decided, I assume I would need either metal or wood.

I am considering how to heat it in winter to get the most bang for the buck. Is insulating the ground of the greenhouse from the earth a requirement, or a good idea? I don't know if the greenhouse would be wide enough for meaningful heat from compost. I don't have any animals to stuff in there, would prefer not to just to keep things simple. I am considering throwing in some geothermal cooling, as in digging deep trenches, throwing tubing in there, and using it to heat and cool the greenhouse.

I'm trying to get everything laid out, so I can have a shot at doing things well, and properly. Measure twice, or even thrice, then cut once.

Thank you for any and all help.

lawrence has a video of his design, maybe search for it  here?

Will do, thank you for the lead!

I'm am still trying to develop the perfect green house.  Things that have worked for me: the ground where I live is pine duff over pumice so the pumice is more or less lightweight sand. Building a wofati style would have been cost prohibitive for me at the time. I built 4 foot tall raised beds that went around the interior perimeter of the greenhouse the only break at the door. Essentially creating an above ground wofati. I picked up a trailer of moldy hay for just hauling it away and placed the bales in the beds filling up the base so I didn't have to fill them entirely with dirt.  A hay hugel.
My next project will be a green house that has the raised beds not only inside but extend three feet beyond the greenhouse structure. My intent is to scavenge any water that comes off the greenhouse. In addition with roll up sides I could drape the sides over the external beds or drop it straight down for the original greenhouse foot print. Ideally I will be able to line the beds and they will be a reservoir for self watering beds.  I look forward to what others suggest and what you decide to impliment.

Hi Riley,
I will start by saying that I am not a greenhouse expert, but I can totally understand where you are coming from with your questions. I had so many of the same ones myself. I was researching the best, most sustainable, most effective greenhouses. From heating/cooling, to insulation, to roof pitch, underground or above ground, phase change materials, etc. And it was a ton of fun, and I still want to build one like that, but reality helped me realize most of that stuff was overkill for what I needed.

Don't stop your desire to build the best... but in the meantime, maybe try building a simple one and get used to that first. In my case, I live in Maine, this is a cold climate, and I learned ventilation was a huge problem even here. I would never have thought that.

Again, I don't want to dampen your zeal, but I have seen way too many people spend thousands on a "perfect" greenhouse, and barely use it. I'd rather see someone build something for a few hundred that does 85% of what they want, and actually use it and learn from it.

I would highly suggest two resources from the same person. I have linked to a youtube video below. Skip the tomato part and you will see Eliot describe several VERY simply greenhouses for very little money. Second, I would highly suggest his book "Four Season Harvest". In it, he describes how he grows greens year round in Maine (a zone or two colder than yours) in unheated greenhouses.

That is a great video, I loved the clips for the tomatoe plants and string.

Unless you plan to heat the greenhouse to 70 degrees F all winter, insulating the ground beneath it is a bad idea. The ground is a year-round source of around 50-55 F warmth in moderately cold climates (zone 6-4 or so), and will help keep your space above freezing until it gets really cold outside. It could help to run a strip of buried insulation around the edges of the greenhouse to help keep the cold from getting in under the sides.

If you have any slope to your land, especially a southern exposure, it would help to dig down on the uphill/north side and make a masonry wall (could be just stacked cinder blocks) to minimize exposed glass/plastic on the cold side. The wall would trap solar heat all day and radiate it back at night. It would also get the floor/bed level a bit below grade to get more earth warmth. For really cold or windy climates, making an insulated or bermed north wall makes sense, as you will get little or no solar gain in winter, only radiant heat loss all day and night. If you like raised beds, elevating the ground all around to bed level, or digging walkways down, or a combination, will give you plenty of headroom while not wasting more height of heated space than the plants need.