What are your best tips for a new greenhouse owner?

October 22, 2007 11:42 AM

What are your best tips for a new greenhouse owner?

I'd like to learn how to use a greenhouse. Here are some of my questions:

- is it possible to use it year round? I live in virginia

- what should I know about setting it up (inside)? Any tips on best practices?

- what can I grow inside? While I like flowers and ornamental plants, I'd love to use it for "growing my own food"

- do you have any stories to tell about your own greenhouse?

- do you have any suggestions for absolute no-no things in the greenhouse?

- anything else you think will help a complete newbie like me

- links to blogs you like by greenhouse owners, and other sites where I can learn

Thanks.

posted by adriana to home & garden (6 comments total)

I built a small harbor freight greenhouse (8'x6') last winter in my tiny San Francisco back yard. Since then I have been trying to get all sorts of food stuff to grow in it.

I've had good luck with turmeric, ginger, lemon grass, peppercorns (piper nigrum), a handful of peppers, some herbs (parsley, cilantro, shiso, nepitella), and salad greens.

It's too early to tell if the other plants will produce any fruit - cacoa, passionfruit, papaya, mango, pitaya (dragonfruit), vanilla (planifolia), miracle fruit, bananas, and mangosteen are all growing slowly and setting new leaves but not yet producing anything useful.

The green house has been incredibly convenient for starting seedlings - this summer we had much better production from the garden than previous years and nearly everything was started from seed in the greenhouse.

Covering the floor with rocks and using tubs/barrels of water for passive heat storage has made it much easier to maintain a reasonable temperature. The water tubs provide heat at night and evaporative cooling during the day.

For shelving I use plastic storage shelves from home depot. I added more insulation with plastic sheeting attached to the walls and ceiling with foil tape.

Good luck!
posted by foodgeek at 11:56 AM on October 22, 2007

Caveat: I have a greenhouse for my carnivorous plant collection (and some random orchids and bromeliads), so my advice is geared toward someone wishing to keep tropical plants in a dry temperate climate.

I put a layer of thick EPDM pond liner as the flooring in mine. The black rubber helps hold heat/humidity in and keeps random beasties from coming up through the ground. I've thrown a few raised rubber doormats on top of the EPDM to keep foot traffic from wearing holes in the liner.

A thermometer/hygrometer is wonderful, one with a several day memory is even better.

Mine is positioned where 2/3rds of it is in filtered sun/shade, with only a corner getting direct sunlight. I've also hung shade cloth inside to help diffuse the light. Direct sun will really spike the temps inside, which, depending on what you are growing, will make your plants happy or cook them. For colder climates, and if you've got the room, try to align the roof ridge of your greenhouse east to west. This gives you maximum sun exposure.

Seconding the advice of tubs of water to help store solar heat.

One problem that comes up in greenhouses with inadequate air movement is mold/fungus developing on the plants. I run a swamp cooler in there during the fall/winter and a regular fan during spring/summer. A GFCI is essential if you are planning to bring electricity into your greenhouse.
posted by jamaro at 12:54 PM on October 22, 2007

I know from sad, very recent experience that moving a greenhouse, even a little, can be hazardous. If the metal frame is at all flexible, you can easily put too much stress on the glass panels and shatter them. This happened to me just yesterday, right after I'd spent several hours replacing one of the panels. Damnit!
posted by MrMoonPie at 1:29 PM on October 22, 2007

when growing in a glass house you have to be very proactive if you have any fungus, disease or insect problems, because they are very easily spread in a close, warm, moist environment.

be careful what you spray with if you have any edibles in there. pyrethreum will take care of insects, not sure what you would use for other problems that may arise.
posted by Dillonlikescookies at 5:57 PM on October 22, 2007

You need to read something by Eliot Coleman.

The one for you is probably Four-Season Harvest.

I worked down the road from his farm this summer, so I got to see some of his greenhouse projects first hand. He's a brilliant farmer.
posted by bubukaba at 6:34 PM on October 22, 2007

I live in Baltimore, so I'm in a similar climate, and I inherited one when I bought my house. It's set away from the main house, so there's no shared heat in the wintertime.

The previous owner grew orchids year-round, so the greenhouse was built with hard plastic front and back sides, and the long dimension is rolled UV plastic sheeting. He set it up so that the air cavity between two layers of plastic sheeting served as an insulator. The walls below waist level are lined with Celotex (foam insulation). It has a professional-grade QMark shop heater in one corner which is linked to an electric thermostat. I replaced the dual-ply plastic with a heavier single layer two years ago.

Now, my experience: Heating it in the wintertime would be prohibitively expensive unless I reinstalled two layers of plastic and beefed up the insulation. Because it's set up as a sealed environment, it's not currently acceptable for growing hothouse vegetables–I need to install a fan and adjustable slats on the side opposite the door for proper pollination and ventilation (see jamaro's comment above-we have terrible powdery mildew problems where I am). I did install a drip irrigation system which worked very well the year I tried it; parts are readily available online for PVC piping systems.

The dream is to convert the whole thing to a hothouse/vegetable setup and grow more of our own food as much as possible. I'd like to be able to install a solar panel for basic electrical needs and hook our rainbarrels up to the irrigation system...but work on the main house comes first.

Good luck!
posted by idiotking at 10:24 AM on October 23, 2007