The greenhouse has now been tested in a freeze, and I'm happy to report temperatures stayed above 36 degrees Fahrenheit, which is what I set the thermostat to run the heater at. While everything else was covered in thick frost, the greenhouse was a sanctuary for tender plants.
Some of my orchids are from subtropical climes or high elevations in the tropics that can tolerate or even enjoy temperatures below 50. One of them is Lepanthopsis astrophora 'Stalky'. This tiny miniature is responding to the cooler, humid conditions in the greenhouse by pumping out a cloud of tiny, amethyst star-shaped flowers. You can see them developing in the photo below. When open, they're only slightly more than an eighth of an inch across, but can be produced by the hundreds. The bright red foliage below belongs to Agapetes 'Ludgvan Cross'
On this side of the greenhouse are a few orchids, bromeliads, and gesneriads that can tolerate chillier conditions. Also my vireya rhododendrons, which love a cool, humid environment. I was experimenting with some of my begonias here, but the only one still in the greenhouse is 'Little Brother Montgomery', behind the rosemary on the left which was tucked inside during the cold snap. I planted two other rosemary varieties in the ground this summer, but every time I do, it seems we get some extreme weather event that kills the recently planted herbs, so I planted a third in a container to move inside as insurance. This time around, all three survived. Maybe the curse is broken!
Over on the other side, I've got a stand covered in tillandsias and Schlumbergera (Thanksgiving and Christmas cacti), my Lapageria rosea, Agapetes, Crinodendron hookerianum, and Cryptanthus pups that I'm experimenting with to see how much cold they'll tolerate. They seem to be doing fine so far. I've also got an assortment of seeds started, and the big container on the right is full of lettuce seed, which has finally started to germinate. The company that builds these greenhouses offers smaller shelves that are half the width of these. I want to add some to this side to make more room for seeds and smaller plants.
The succulents and a few drought-tolerant bromeliads are organized in this corner for watering purposes, or lack of watering in this case.
Underneath are a few larger plants like Blechnum gibbum, Abutilon megapotamicum, and other tender and semi-hardy plants.
I love having access to a greenhouse to keep these plants that, while tender, wouldn't appreciate the relatively dry heat and darkness of the house. Though I am itching for more seed space. Those shelves will help. I have a fan set up on a timer to run intermittently, circulating the air. The closed vents caused a buildup of condensation and still air that made the perfect environment for fungal problems. Moving air makes the environment slightly less friendly to such pathogens, though I've also started treating things with an organic fungicide for extra measure. I had started to lose some seedlings to damping off, but the combination seems to have stopped it for now. I wish I had taken advantage of the warmer weather last weekend to open up the greenhouse and air it out a bit, but I didn't think of that. Ah, well.