The other day I was at a conference and attended a lecture on building terrariums. There was a lot of mumbo jumbo about what terrariums actually are, with lots of descriptions of various glass-fronted cases and hand-blown vessels. This was followed by a lot of suggestions, mostly in Latin, of plants that work well in these container gardens.
Frankly, there was too much technical information and not enough down-to-earth information on a subject that should interest all Alaska gardeners. Why? Because terrariums are an easy way to have plants that will actually thrive during the winter months when many indoor plants simply will not.
Yes, technically, terrariums are sealed containers that contain plants in an ecosystem that lets them grow with minimal care. Practically, the speaker should have been talking abandoned fish tanks, at least for starters. These make the easiest containers to use and are without question the easiest to come by. In fact, you might even have one left over from that last garage sale you held. Of course, you can use anything that is clear and can be covered. Anything from a wine or brandy glass to a fish tank to a turtle cage.
The big drawback of terrariums is that they don't drain, because they have no holes. This means that a lot of care has to be taken to ensure the soil in them does not become so wet that it turns anaerobic -- a situation in which there is no air and roots die. Dead roots leads directly to dead plants.
My speaker had all sorts of complicated mixes. I have a different idea.
First, figure out what kind of plants you want in your terrarium. The choices are basically two: succulents (in which I include cacti) or leafy plants. If you go the succulent route, put about an inch of sand down. Then place about an inch of gravel or stones on top of that. If you are planting leafy plants, cut the amount of sand used down to 1/4 of an inch.
Once the base is in place, you will need a soil media. If you are an experienced grower, you can use a homemade mix of compost and coconut coir. Or, you can buy a terrarium mix at a nursery or box store. Once you do, you will get a feel for how to make your own, not to mention a list of possible ingredients from the label.
Depending on the size of your vessel and the size of your plants, you again have two choices. The first is to simply transplant plants from their containers to the terrarium. Keep the root ball if possible. Some folks use tweezers or chopsticks to place the plants, especially with a small container. The second choice is to plant the plant still in its container. Roots will grow from the drainage holes. If the plant needs replacing, it is easy to pull out. It is also easy to move around and arrange when designing the terrarium in the beginning.
Once your plants are in the terrarium, you will need to beautify it and "borrow" from nature. You want your scene to look natural. Place rocks around, for example, so that they look like they have been there forever. Consider introducing a couple of twigs to make a tree or to become a log on a forest floor. Add lichens to the surface of the soil or consider laying down moss. There are all sorts of things you can do, including adding toys to create a scene (no matter how kitschy the results). One of the great things about terrariums is that you are not limited to just a few possibilities.
The next step is to clean things up. Brush or blow soil off the leaves. Clean the glass. Clip off and remove any leaves that were damaged in planting. You don't need me to tell you what to do.
Where to place your terrarium depends on the kind of plants you used. Succulents like bright light, and leafy plants, just a bit less so. For cacti and the right succulents (low ones) you can even use the light that came with the aquarium. If it doesn't put out too much heat, you can use it for leafy plants as well. (There is a problem solved.) That way you can put your terrarium anywhere, even a room without windows.
Finally, watering. You have to be careful as there is no drainage. Use either a dropper or a tablespoon to water. Too much water and you will have lots of condensation inside your container, at best, and waterlogged, dead plants at worst. A covered terrarium can go three weeks or more without adding water. If you leave the top off, you should check yours every week.
There you have it. No lecture, either. Terrariums are easy. They are also perfect for Alaska. They are not affected by drafts and can be put right up against a leaky window. They are easy to light. And, best of all, they are easy to make. Frankly, I didn't need to sit through an hourlong lecture to learn how to plant a terrarium. It is just like planting the garden outdoors, only on a miniature scale. Just plunge in and do it. It isn't hard.
Jeffs Alaska garden calendar
House plants: They are in all over the place. Buy some. Of course, you should have an artificial light set up to help yours get through the winter.
Fungus gnats: Cover your soil with newspaper to prevent the adults from laying eggs. Let the surface of the soil dry out between waterings.
Thanksgiving and Christmas cacti, jasmine plants: Place yours where they will get natural light and keep cool, 50 to 55 degrees. These two moves will induce buds.
Jeff Lowenfels is co-author of "Teaming With Microbes" and author of "Teaming With Nutrients." Contact him on his website at teamingwithmicrobes.com.