I would love to have a greenhouse. I have a Pinterest board full of beautiful glasshouses, ranging from cute cottage types to poly hoop houses. I hate the cold, and the idea of having a warm place to garden through the winter seems like heaven to me.
But.
I live on the 32nd North Parallel, in Jackson, MS. We’re at the same longitude as Tel Aviv, Israel and Savannah, Georgia. It gets hot here. Damned hot. Last year (2023) we had 119 days where the high was over 90 degrees. We only had 17 nights when it went below freezing. A greenhouse would be nice perhaps a month a year, and unbearable the rest of the time.
But a warm place in the winter is not the only benefit you get from gardening under cover. Being able to control the environment, ergonomic plant benches, and storage are also things you get from a greenhouse. I joked that I needed the opposite of a greenhouse. But then I got to thinking.
I built myself what I call a shade house. It’s basically a lean-to against the fence. It faces south, and gets full sun the whole year. If I had a greenhouse, this is where it would go. It’s 6×8, and is made like a lean-to pole barn – 4×4 uprights and 2×4 girts. The lath is pressure treated 5 and 1/2 inch wide fence pickets, ripped to 1 and 13/16 inches, so I get three pieces from every picket. They are spaced one picket width apart, so they let 50% sun through.
I originally planned to have lath for the overhead, but it rains 1/3 of the days here, and I plan to use it mostly as a small nursery and to house my plant’s waiting to be planted, so I decided some cover would be nice. The polycarbonate sheets (5 of them) are smoke colored, and came from Home Depot. They let 35% light through, and block the UV. I put it up just like you would tin on a pole barn.
I intend to put crushed rock on the floor, and I think I can manage a small mist set up under the back bench. My plants waiting to be put out are ridiculously happy in there, and it’s at least 10 degrees cooler inside than outside.
I mostly plant perennials, so I can “winter sow” them here, and the few vegetables I start before the last frost day can be started in the shed under lights, the way I do now.
It’s worth noting that I didn’t invent this – orchid growers use something similar called a lath (rhymes with math) house. These days they mostly use shade cloth, but back in the day used strips of wood, or lath.
I plan to greatly increase the number of plants I have in the garden, and plants are expensive! So, I hope this will make it easier for me to grow them from seed and from cuttings. I’ll keep you posted.