I’ve been gardening in the PNW for about 5 years now. My home is generally very shady and my raised beds were in the one area that gets just about 6 hours of full sun. My zone is 7b or 8a. I’m still trying to figure that one out if I’m being honest.
Generally speaking, I do OK with my veggies. Early tomato varieties produce enough, I get a few zucchinis, green beans do OK and squash are hit or miss for amazing or OK depending on the year.
I splurged and bought a “greenhouse” on Wayfair. It’s 12’x16’ and has a max height of 9’ and a min height of 6’.
My plan was to grow most of my crop (warm loving) permanently in the greenhouse but now I’m getting nervous. I’ve read that fans are required for this and sometimes, it may not be enough. This structure does have 2 vents + a large door but will it be enough? Am I going to have a 100F+ hot house that kills my babies?
I can’t plant outside of the structure as it took the place of my original fenced in garden (the only spot that actually gets sun).
Thoughts? I’ve been lurking for a while and I see that a lot of you have great knowledge to share.
I think I’ve shared enough data but if you need more, let me know.
TYIA 🤍🤍
by DeannaTroy
5 Comments
I no know nothing, but I like greenhouses and that one looks very nice!
Shade cloths are your friend. I got a 40% shade cloth that I plan to get up here closer to summer. If you hang it above the greenhouse and not touching it, it’ll bring your temps down significantly during hot days. Combine it with some fans and I use the auto vent opener as well you can keep it cool for your plants.
I believe some people put the shade cloth inside, but that does pull more heat in and is counterproductive if I’m not mistaken. You can also mist the inside during morning and other small stuff like that but shade cloths, fans, and vents are the go to for keeping the temps from getting too high and killing ur plants.
Texas 8b here. In the summer, pre modifications, my greenhouse would easily hit 120F+. This is just with opening the vents and door so most likely you’ll experience something similar too.
The most important thing you need to add is an exhaust fan. You need to completely circulate the air within your greenhouse at least once per min but more the better.
Temperature controlled vent openers, shade cloth, mist system were also things I added too. Sometimes I’ll throw a small swamp cooler in there too.
Air movement is critical. Heat aside, plants will do much better with air movement beyond passive air movements through opening doors and vents.
I’m in southern Arizona, zone 9b, so bit of an extreme case. I have 30% shade cloth (my greenhouse material is semi-opaque already), 4 roof vents, often have both doors open in summer, and 2 fans. One of those fans is also a swamp cooler, and I turn on that functionality in spring/summer to shave off another 10°f or so.
Being in the PNW, your air is plenty humid so a swamp cooler likely wouldn’t be of much benefit. A couple of big fans though, yeah.
We greenhouse garden here in Western WA, and yes, you will need fans. On a sunny day in the low 70s, it can get well over 100 inside and that’s just too much for many plants. Temps like that will also kill the pollen in your tomato flowers so they cannot be successfully pollinated, meaning you will have fewer tomatoes setting.
You should be able to find fans to fit your windows from a greenhouse supplier, and many of them will have temperature controls so they will run automatically.