Terrarium: A MAR-velous Glass Garden

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Originally known as a “Edwardian Case”, terrariums have been around for about one hundred years. I had my first terrarium when I as eight years old in second grade. We grew beans in cotton in glass jars. It was exciting back then to watch things grow, particularly without dirt. Today, I get a lot of enjoyment from my terrariums as they are intriguing to guests who always find them interesting and beautiful. When they find out how little care is required, they immediately want one.

Terrariums can be covered or uncovered. I prefer the covered version for the simple reason that it requires less maintenance. A covered terrarium is a self-sustaining system where the water vapor is trapped creating a high humidity environment. This is a good thing because you only have to water it three to four times per year. How’s that for low maintenance?

Here’s what you need to build a terrarium:

A container. While there are containers sold specifically for terrariums, any clear glass or plastic container with a cover will do. It all depends on how big and how fancy you want to get. Examples include glass jars, jugs or bottles; fish bowls or tanks work well too. I prefer glass apothecary jars with tops which come in various shapes and sizes.

Pea Gravel. Pea gravel is small stones that are used for drainage and can be found at pet stores and garden centers.
Horticultural Charcoal. While many will tell you to use either charcoal or pea-gravel, I believe that you must use both for the best result. Terrariums are damp environments and charcoal will keep the soil from developing as sour odor.

Potting Soil. The best soil for terrariums is a high quality, sterile potting soil because it has a high amount of organic matter.
Plants. Before you purchase plants, first determine where you would like to place the terrarium because light conditions and temperature will affect your choice of plants. They should have similar requirements. Low-growing, dense plants are best. Do not overcrowd them. Make your selection based on size, color and texture.
Spray bottle for cleaning the sides of the terrarium after planting.

So, let’s get started. The first thing you need to do is to sterilize the container. This can be easily done in your dishwasher or by washing it in hot soapy water. Make sure to rinse and dry thoroughly.

In general, roughly one-quarter of the container will be used for the drainage materials and soil. Just as you would layer an English Trifle or parfait, begin with a layer of gravel, at least one inch deep depending on the size of your container. Sprinkle a thin layer (about one-half inch) of charcoal on the gravel and follow with the soil. This layer of soil should be a minimum of 1 ½ to 2 inches deep.

Now to the planting. It is very important that your plants are insect and disease free. Make sure that you remove any leaves that are damaged, yellow or show signs of disease or insects. Keep in mind that there will always be a front and a back side. Place the taller ones in the back. An interesting rock, shells and/or driftwood that has been washed and dried are perfect additions and will give your terrarium a finished look.

Once you are done planting, spray the sides of the container and the leaves of the plants to remove any dirt that got there while planting. This is enough water at this time. The next day, mist the plants again while observing the water level at the bottom of the container. That level should not exceed ¼ inch. You will want to keep the container uncovered until the leaves are completely dry. Then cover. Your job is mostly done.

That is until you need to water. In four to six months, remove the top and add only enough water to moisten the soil, about ¼ cup. Once again, do not cover until the leaves have dried somewhat. Over watering will result in standing water and that’s never a good thing. Less is more in this situation.

How often you will need to water subsequent to this depends on how tightly the lid fits on the container. Condensation or the lack thereof, is your prime indicator. If there is a lot of condensation, remove the lid until the plants dry out. If there is none, water just enough to moisten the soil.

A mistake that is often made is to crowd too many plants into the container. Be selective. Remember that your terrarium will look empty in the beginning but once the plants begin to grow, your terrarium will soon be lush and beautiful. Do not put plants so close to the sides of the container that the leaves touch it. They will become wet from the condensation and may develop mold. Should you ever need to replace a plant, follow the same directions as when you built the original terrarium.

Some of my favorite plants to use are: mosses, Creeping Fig, Button Fern, Piggyback plant, Swedish Ivy, Ti plant and Parlor Palm.

This project is great to do with kids. It makes a great gift for grandparents or elderly friends of the family who no longer garden and would appreciate bringing a little bit of Mother Nature inside. Your terrarium will give you years of enjoyment for very little effort and nurturing. Would that more relationships could survive under these conditions!

And there you have it.