During the winter I started to get antsy for warm weather and spring colors, so choosing to invest in a green house was a natural extension of my desire for spring. The greenhouse allowed me to use the space on my patio more efficiently by allowing me to start my seeds earlier and protect my outdoor plants from the lower temperatures.
I got the idea of using a greenhouse from the book The Self-Sufficient Gardener by John Seymour. In the book Seymour says that “the primary function of a greenhouse is for propagating seeds and growing tender crops” (204), which is exactly what I planned to do. This book was particularly helpful because Seymour lists the various kinds of greenhouses, their pros and cons, and the different materials that can be used to build them. I used this guidance to pick a greenhouse that would work best for my budget, my environment as well as my space requirements. The one I have is a 4-tier mini green house that fits perfectly in the limited space on my patio. It’s made of a light weight metal and uses a plastic tarp that ties around the supporting poles and is easily removable.
It’s important to note that metal “reacts more strongly to hot and cold than wood and therefore cools the greenhouse in winter;” and that while plastic is cheap and easily transmits light, “it will only last one or two years, and is very easily ripped” by strong winds (205). I chose these materials because Georgia has a humid subtropical climate with typically mild winters and hot summers, so the conductivity of the metal is not a significant issue. My patio is also screened in, so my greenhouse is not exposed to any elements other than the sun and mild wind. Therefore, I’m not in any imminent danger of ruining my plastic covering any time soon.
Materials aside, the greenhouse worked like a dream on into April. My plants and seedlings flourished until mid-April when the weather quickly went from mild spring to hot spring. I found that the plastic covering had trapped heat in the green house during the day and caused a lot of condensation. Even though the heat would dissipate at night, the environment in the greenhouse was too humid to allow my plants to properly grow. While none of my seedlings or plants succumbed to frost, many of them died because of damping off, which is a term that encompasses many soil born diseases that attack a seedling at the stem closest to the soil when conditions are too wet. Damping off causes seedlings to collapse and eventually die. I wasn’t able to keep my affected seedlings alive, but have since found some great advice on prevention and treatment in “Damping-off Diseases in the Garden” and “Preventing Seedling Diseases in the Greenhouse.”
Since beginning my urban gardening journey, I’ve learned to identify damping off as well as a few other diseases by reading Small Plot Big Harvest by Lucy Halsall. Although Halsall does not specifically talk about diseases that often occur in greenhouses, she does list many common diseases, pests, and nutrient deficiencies as well as how to treat them. It’s been a big lifesaver in my greenhouse and my porch!
Although my greenhouse is simple and I initially had a problem with damping off, I had immediate success in growing green beans, sunflowers, zinnias, jalapeños, a marigold, dahlias, lily of the valley, and herbs. I even had initial success in growing salsify, leeks, and watermelon radishes, but the Georgia summer wasn’t so kind to these cooler climate veggies.
I removed the plastic covering in mid-April, so my greenhouse made an easy transition to a shelf for my plants. I really enjoy how multifunctional this particular greenhouse has been. Currently, I am using the shelves to continue growing my herbs as well as my snapdragons and mixed wild flowers. Come mid-September I anticipate using the plastic covering again to continue growing my snapdragons, mums, and sundry winter flowers!
Have any questions about your greenhouse experience? How about your urban garden or house plants? Contact The Gardern Generalist on our site or on one of my social media platforms: Pinterest, Instagram, and Tumblr. I’d love to hear from you! Keep a look out for my next posts chronicling my success with dahlias and a throw back to spring at the Atlanta Botanical Gardens.