TO Greenhouse or Not to Greenhouse

Good Morning y'all.

My name is James but I go by Shames at times.

I have been studying hydroponics and aquaponics online. Just getting started on my first greenhouse. I live in Northern Arizona where we get all four seasons. My greenhouse plan is a lean-to with the roof facing South to capture the heat and sun light. I think I have gotten enough info on when to add shade screening and venting the heat. What I need some help on finding is more info on the sides. I have found for FREE vinyl windows (4'x4', 4'x5', and 5'x8' also a vinyl patio door) and they all work. I was going to use the patio door as my entry and open the windows for air.

My question is, should I have more air flow? I will have 4 points or air entry plus a 30" patio door. They are all screened and that I will remove when I need the bees to visit. Is there a formula (funny, I don't think there is) as to how much air I need is relevance to my square footage?

Any advice is appreciated.

Thank you and God bless,

Shames

James:

Welcome to the forum.

My greenhouse is 120 square feet. It has about 16 square feet of roof vents, and about a 28 square feet door vent.  It still gets plenty warm in there. The roof vents have auto-openers on them. I really really like that feature.

THank you Joseph,  I appreciate you sharing that.

Shames

Welcome to permies James !

I once had a partially underground greenhouse in Wyoming. About 12 X 20 feet. I used two old windows on the roof to make vents and had a door on one end and some removable windows on the other. No screens, I just let the bugs come and go.
Everything I grew in there went nuts and I loved it. It was a pretty dry High desert area so not much worry about things getting to wet in there.
Have you thought of going underground some?

I have thought about going underground, I have seen some amazing examples online too, I just can't in my neighborhood. Our lots are too small and utilities are everywhere. My plan is to move out more in to the country in a few years and I may try it then.

I have an idea about the weather up there so how did your greenhouse handle the winter? I mean the top sticking out of the ground.


James

My growing season was generally 3 months long but the green house gave me about a month on either side of that. During the winter it would heat up during the day but freeze again at night so I didn't really use it. If I would have known more about permaculture back then I would have pushed it a lot more.

I've been living with a seasonal attached greenhouse in the high desert for 20 years and I love it!

Our outdoor growing season is about April to September, but in the unheated greenhouses it is year-round. When my students are out there ice skating from late December to early February, I've got arugula, mustard greens, claytonia, dill, calendula for color, hunkered down herbs, and a couple of local varieties. This year I've also planted mache and spinach which should do fine too. The greenhouse does go down to a few degrees below freezing on those January nights, but because there's no wind, those hardy plants don't seem to mind much. Some of them look wilted early in the morning but perk right up when it warms up. Occasionally I'll go out and cover them with a coat or towel when it seems like it'll be an unusually cold night.

But I would recommend much more ventilation. In March our greenhouses start to get roasting hot in the daytime, some plants get killed, and aphids proliferate. It's much harder on the plants than cold winter nights are, and it can also be deadly for seedlings we start for the outside garden. The greenhouse attached to my own living quarters can have the end removed, so I do that in March, but then in April it gets roasting hot even with the end open.

We remove our greenhouses entirely for the summer. We make them of UV resistant polythene film, attach them under the eaves of the south side of the houses, roll them down in autumn, and roll them up and tie them under the eaves in May. We try to include a canvas cover over the roll, but even without it, the UV-resistant film lasts at least 7 years, probably more with better care. And then the plastic has another several years of good service as a tarp.