Compared to the Midwest United States, where I grew up, winters in Northern Virginia are rather mild. Most daytime highs are well above freezing. Occasionally, however, we get a blast of very cold, arctic air, like the one rolling in today, which causes worry for the well-being of my bonsai, accustomed-as-they are to this milder climate.
Some of you may have read about the expansion and improvement of my winter storage cabinet. (You can go HERE if you want to check it out.) I’ve been thrilled with it’s performance thus far. When closed, this enclosure is generally six to ten degrees warmer than outside temperatures, and I attribute that difference solely to the radiant heat from the house and enclosed window.
As good as this is, the forecast is calling for single digit temperatures (Fahrenheit) which is cause for concerns for a few of the more tender, less cold-hardy specimens I am keeping here, so I have decided to add another heat source. This…
What is it?
This is a small radiant heater that I have fashioned from a number of unused terra-cotta pots. You may have seen a similar candle-powered version which is a great emergency strategy for power outages and the like. This one is a bit different because it is electric.
When I expanded in the fall, I included the exterior power outlet inside the frame of the enclosure. This makes putting my heater into the cabinet super easy.
Let me show you what I have.
The bottom half of the heater is a terra-cotta pot with an old clip lamp I had lying around. The cord extends through the drainage hole, and the lamp is secured in the center pointing upward.
The bulb I am using is a ceramic heat emitter designed for pet reptiles. You should be able to find a similar product wherever you buy pet supplies. This sort of bulb comes in 60 watt and 100 watt varieties (if not others). I am using the smaller bulb, but could increase the heat output with the larger if I was so inclined.
The top half is a series of ceramic pots bolted together through their drainage holes. Suspended above the heat lamp, these absorb and gradually radiate the heat into the space. This many pots may not really be necessary with a consistent, electric heat source, but I assembled these originally for use with candles, and have since adapted to the electric version I am sharing today.
There’s nothing else to it, and I’m sure you could fashion something similar with some spare pots and a little ingenuity.
I have placed my heater on the ground level of the enclosure — heat rises after all. I plugged it in to get warm and sealed the door so the heat can build up a bit. I hope the heater will give a little boost to keep the space even warmer than outside where the temperatures will be dropping all day. We expect arctic winds and sub-freezing temperatures by the evening.
In the meantime, I’ll be checking the thermometer that hangs within from the warmth of the house. Keep your fingers crossed for me.