Tag Archives: greenhouses

why a greenhouse?

I find that I’m asking myself whether I need the greenhouse anymore. Left over from an obsession with warm-growing orchids a couple decades ago, it sits in the middle of some prime real estate in the every-shrinking back yard.

Its current incarnation is more shed than greenhouse, with bags of potting mix and pots taking up most of the space. Still I continue to use it for some propagating. Because of the famous greenhouse effect temperatures inside during the daytime can climb ten to twenty degrees higher than outdoors–and that’s with heavy shadecloth on the western exposure. Even at night it stays a little warmer than the outdoors. Before sunrise during a cold snap a week and a half ago I looked at the thermometer inside: 42 degrees. Pretty cold, but it was but four to five degrees higher than a nearby thermometer outside.

The new patch of lettuce outside. Where's the lettuce?
Here's a little recycled sixpack that I seeded with lettuce five days earlier. Unlike the bare patch outside, the seeds are germinating.

The extra warmth can help seeds germinate a few days earlier than outdoors. And once the plants are up they can grow quite a bit faster. The warm spa temperatures inside the greenhouse, combined with some protection from marauding nature, can give you a leg up on the season.

I showed this photo of germinating bladderpods a couple of weeks ago. These plants are less than two weeks old.
And these are the same bladderpods last night, showing lots of luxuriant growth. I'll be repotting these soon and getting them ready for planting in the garden.

If you’re occasionally impatient like me it’s nice to see bigger plants sooner.

And this last photo shows another advantage of the extra warmth. These are yearling seedlings of the North American pitcher plant, Sarracenia. All three pots were started in the greenhouse a year ago, but the one in the middle spent most of the summer outside in strong sunlight. These plants are supposed to like the intense light, but you can see that they were more partial to temperatures that reminded them of the South than intense sun. For plants that ordinarily take five years to mature, it’s looking like the extra warmth can take a year or two off of the usual time. It’s cool to have a greenhouse to save a few weeks but having it help shave one or two years is pretty persuasive.

So as I talk myself through all this it’s looking like I’ll still want to have some sort of greenhouse, even in Southern California. But it might not be this really inefficient and poorly located greenhouse. And did I mention that the current building has termites?

The replacement might be separate little structures. Maybe they could be enclosed carts and have wheels so that they could be repositioned to take advantage of the best sun angles. And if they’re on wheels they could be stuck in a corner of the yard if they’re not being used for propagation. And something like a cart wouldn’t waste space on aisles to walk down.

Well, there are lots of possibilities, and I’ll be thinking about what to do. I’m one of those people who likes to stare at a problem for a long time, but maybe in a few months you’ll be reading about the next big garden construction project.

“plants are up to something”

I loved this banner at the Huntington. Hanging outside the instution’s conservatory building, it announces that the exhibits inside might be more oriented towards education than the gardens that make up the rest of the grounds. The conservatory also houses plants that might have special needs beyond the “just add water” plantings located in the subtropics outdoors.

Pass through the front doors and you step into a greenhouse space containing a miniature tropical rainforest, a cloud forest and a bog garden, along with lots of educational signs and interactive exhibits scattered throughout the space.

For me most greenhouses and conservatory gardens suffer from being examples of nature-in-a-can, and to me they tend to look and smell and feel very similar in their hermetically sealed spaces. If only the Huntington were located on some barren snowy tundra plain, where entering a tropical rainforest on a cold winter day might be a stunning revelation.

Even on this cool December Southern California afternoon, the temperature differences between inside and out weren’t that pronounced. And the lush plantings outside the front door seemed to mirror the lushly planted indoors. Still, lacking the stunning contrasts that might help to set the conservatory apart from the outdoors, it was a fun place to connect with a lot of cool plants. When the Huntington’s giant corpse-flower (Amorphophallus titanum) blooms, there is where you’ll find it. It wasn’t blooming, but there were lots of other interesting things inside.

The bright red-orange trunks of the sealing-wax palm, Cyrtosstachys renda were pretty amazing.

My visit was two days before Christmas, so there were this holiday display of poinsettias and amaryllis. At first they seemed like gratuitous holiday decorations but then the aha moment struck me that these plants originate in the tropical and subtropical belt of the Americas.

Floral parts of a large anthurium species…

This carnivorous Asian pitcher plant (a species of Nepenthes) greeted visitors as they entered the cloud forest display.

And dropping down into the bog garden, American pitcher plants, Sarracenia, and sundews, Drosera sp., let viewers see other ways plants have taken up carnivorous ways. (Do you detect a theme of the conservatory playing up the idea of scary, creepy plants, going from these carnivorous species to the stinking giant corpse flower that lines up visitors by the hundreds when it does its thing?)

At this point the blogger rambles on a bit: These days it almost seems that every botanical collection feels to have its very own giant corpse flower plant that will draw the visitors when it blooms, something of the way medieval churches tried to draw pilgrims by having unique relics of saints, or how many temples in Asia will claim to have preserved hairs of the Buddha. So it seems that the giant corpse flowers has become a modern secular botanical relic. It’s a little odd, since you can occasionally find the plant for sale on eBay–granted for a good chunk of change–but still nothing much more than you’d pay for a pair of high-end jeans.

Okay, now back to the trip…

I’m coming to the realization that greenhouses always scare me a bit, like I’m entering a world that’s on perpetual life support. Upon leaving the conservatory I stepped outside into the bright December afternoon. Not far away a reader was seated in warming sunlight on a Lutyens bench, enjoying the moment. I’d had a good time on my visit to the synthetic tropics, but returning to the real sunshine and real weather outdoors I suddenly felt free.

in the greenhouse, or, the dictator's wife

greenhouse-euphorbia-outsideI was in the greenhouse Friday morning, watering some pots of seedlings. It seemed funny for a second, because outside the greenhouse it was raining. If I hadn’t gone in there with the hose that morning, the seedlings would have died in the desert for lack of water.

(Left, a Euphorbia characias ssp. wulfenii outside the greenhouse, blooming away in the rain.)

I used to grow and breed phalaenopsis orchids in the greenhouse. It was gonzo amounts of work to keep up with repotting hundreds of plants. And trying to concoct an environment that would fool the orchids into thinking that they were in the lowlands of the Philippines instead of the flats of Southern California wasn’t that easy either. In addition to all the work, the greenhouse was an energy pig, taking as much natural gas to heat as the entire house.

So, end of orchid obsession. End of heating the outdoors and wasting all that energy. (The New York Times has a recent piece on a couple who decided to build themselves a greenhouse. Their heater hasn’t arrived yet, but they’re already way over budget.)


Now that the tropical orchid episode of my life has ended the greenhouse is only heated by the sun via the greenhouse effect. At this time of year it’s handy to have a spot that will help give young plants a head start on spring. That’s pretty much how I use the greenhouse now.

greenhouseclutterAnd, um, yes, for a place to store garden clutter. Sort of a garden shed with windows…

greenhouselookinginFortunately the windows are an opaque fiberglass, so all the mess inside is obscured. Maybe even a little mysterious and poetic. Here are some potted plants as seen from the outside.

As I was watering the plants in my little artificial outdoor desert I thought back to the 1980s. One the stories from the news that has stuck in my brain all these years was a report on Michèle Bennett, the wife of Haiti’s dictator, Baby Doc Duvalier. The couple was bad news all around, and one of Michèle’s vices was that she’d refrigerate a part of the palace so that she and her friends could strut about in the fur coats that they collected. (Compared to her husband’s brutal ways, it all seems pretty minor, of course.)

Mink and fox and chinchilla coats in Haiti. About as rational as a greenhouse full of warm tropical orchids in San Diego, I thought.

I guess we all want a little of of what doesn’t come easily or naturally. But in an age of a growing awareness of the need to live greener it’s good to stand back and see what we really need.

shading a greenhouse

A few years back I wrote an article for The Growing Edge magazine on a fun greenhouse shading system that I’d devised using plywood sheets cut into interesting shapes. I was trapsing around Google Books and ended up googling myself. (Admit it, you google yourself too!) What should run across but the article I wrote, reprinted in a “best of” anthology. You can click here to see the entire article reprinted in the book.

The reprinted article has my shop drawings but doesn’t have the photos of the complete project. So here’s an idea of what it looked like when I was done:


As a post-postscript to the project, if you do attempt doing this, use wider rabbets than shown in the article. It lets you attach the individual shade pieces more securely than I’d shown. Otherwise the panels start to fall apart as the pieces swell in response to wet weather–nothing you want to have happen after investing some time in making your panels! As cool as it looked, my underengineered panels only last about 3-4 years. Using wider rabbets and plywood thicker than the minimal quarter-inch stuff would have made them last much longer.