All about My Greenhouse -- You Can Have One, Too
A greenhouse? Why?Doesn't every gardener wish for a greenhouse? I trundled a kitchen cart in and out of the tool shed with little flats of seeds until after the last frost every spring. My winter projects of potted tropicals and rooting cuttings got too ambitious for an unheated utility room where it never got below 45 degrees and morning sun came in two east facing windows. When my Epiphyllum broke in the wind and I rooted the pieces, 3 huge pots were too many for the utility room along with forced hyacinths and rooted cuttings.
What did you consider when you decided to build a greenhouse?
Costs, of course. Convenience to the house. A place in the winter sun for the pets and plants and me out of the wind. A playhouse, if you will. Size matters, too. Ten by 12 feet is just big enough for my purposes. It keeps me from being too ambitious.
Why did you choose an aluminum frame?
Cost and ease of assembly. I had a collection of old windows that I'd planned to use. I read many posts on Garden Web by gardeners who had assembled and used a Harbor Freight GH with good results. Replacement parts are easy to obtain despite having a long wait sometimes. We gave away the old windows with their need for scraping and reglazing and a huge carpentry effort and undertook a project that was more suitable for two old people.
Isn't a greenhouse terribly expensive?
Less than a nice vacation. This is one of the most inexpensive aluminum framed ones. Reinforcing it for sturdiness, a good foundation, and putting in water and electricity doubled the cost. After four years, a hailstorm took out most of the polycarb panels that were brittle from our hot south Georgia sun. We replaced the panels. The frame is still sturdy. Be aware: An inexpensive greenhouse needs lots of reinforcement to make it sturdy and strong enough to withstand a hard wind.
Can I put up a greenhouse myself?
Help needed depends on how you usually get work done. It was strictly a DIY project for He-who-mows and myself. We put the frame together in the workshop out of the wind, hauled it around to its final location where we added the polycarb panels and installed the utilities to Code.
The water source is simple, a single faucet with a Y connector and two hoses, a short one for watering and misting and a shorter one for filling my watering cans. I hand water because I move things around so much and every pot has a different need.
How do you heat and cool your greenhouse?
We use two small electric heaters with fans and thermostats. If we have a really, really cold night I can also bring in some infrared lights. In a real emergency situation we can use a kerosene heater or a generator. We have some occasional temps in the teens during nights in December to February. Comes the sun in the morning and things heat right back up.
Ventilation is more of a concern than heat most days. There is an exhaust fan at the east end and a mist system for cooling.
Overall temps are moderated with heat sinks: four 50-gallon barrels of water. Lots of stone and concrete and brick used as flooring help take up heat from the sun on cold days. Wetting the concrete helps lower the heat by evaporation on hot days and raises the humidity.
Do you grow year-round?
The heat is too intense in late spring and summer, I thought. However a purple Alternanthera seeded itself under a bench and grew all summer, weaving itself among the pots. A seedling Madgascar periwinkle came up too and survived most of the summer without water. After that I started trialing some plants through the summer inside.
I leave a few tropicals in there through the summer on the floor underneath the mist system. I hung some non-woven material similar to row cover to shade the west end for summer in 2013. In 2014 after that poly stuff disintegrated, I used white plastic tablecloths from the dollar store for shade. I fastened them with binder clips.
What are your favorite plants to grow in the greenhouse?
Many plants that are root hardy here I like to see growing in the winter while the ones outside are killed back to the ground, slow to emerge come spring.
Begonias and Kalanchoe do well as do Pentas and Porterweed for winter blooms. They can go back outside for the delight of butterflies in spring. White Shrimp plant and Persian Shield bloom in winter or early spring in the greenhouse.
Seeds, don't forget seeds! Early start on spring growing, patience with slow tropicals like Pride of Barbados.
What tips do you have for someone thinking of getting a greenhouse?
Daddy always said to estimate the cost and double it; good advice. Plan for a water source and electricity. Get some idea of what it will cost to heat your greenhouse. Pay attention to site and leveling. Find all you can about what others in your part of the country have done. Learn from their mistakes and successes so you don't have to trial those again.
I saw a photo of a driveway paved in broken concrete, stones and brick and copied the pattern. This was an ambitious flooring project for an old woman.
Maybe what you want isn't a greenhouse at all; just a playhouse or potting shed with sunny windows. A place to play and dream should not be beyond your reach.