Terrariums make great, inexpensive gifts

If you're looking for an inexpensive gift idea for a friend, consider making a terrarium. A terrarium as a gift would be a big surprise, and the expense depends on the size you build.

Container: There is no limit to the size of the terrarium container. I've seen them from a pill bottle up to a giant aquarium. The only thing you need to be concerned about is an opening. It needs to be at least the diameter of a dime.

Glass is classically considered best, but there are containers made of acrylic or other types of plastic that make attractive terrariums.

The color of the container also is important. A clear container with a slight tint works best, because you must be able to see the plants in the terrarium to appreciate them and there must be light to make plant food. In the presence of light, water and atmospheric carbon dioxide convert to carbohydrates, which produces the plant's new growth in the form of foliage, roots, stems and blossoms. This process stops if the plants can't get light. A terrarium also needs a lid to keep air out and moisture in to sustain them.

Preparing the terrarium: Start with a clean container. Wash it several times using hot water and detergent and rinse thoroughly. Fill it with a mixture of hot water and a good household disinfectant, such as liquid bleach, to eliminate bacteria and spores that might still be lurking in the container. Use ½ cup of disinfectant per gallon of warm water and let it sit in the container for 30 minutes, then rinse again with warm water. Finally, turn the container upside down to dry thoroughly.

Tools: You need several tools to plant, and they're not expensive. You need a bamboo stick or small doweling, along with a wire coat hanger, to dig holes when positioning plants. Make a funnel by rolling a newspaper into a funnel shape. Finally, you'll need a razor blade inserted into the end of a bamboo stick or doweling.

Now decide the type of terrarium you wish to make -- a desert or tropical garden. Do not combine plants with different cultural requirements, such as cactus and tropical plants, or combine blooming with nonblooming plants.

Plant choices: To add interest, use plants with contrasting leaf size, texture and coloring. The day before, wash off the plant's leaves.

Here are some tall plants that adapt to the terrarium environment: croton, palm, small-leafed philodendron, syngonium or nephthytis (often called the arrowhead plant) and schefflera.

Medium plants include dracaena, small-leafed ivy and fittonia or Chinese evergreen.

Groundcovers suitable for terrariums include baby tears and the small-leafed wandering Jew.

Planting: Place at least ½ inch of gravel on the bottom of the container for drainage. Follow with a ¼-inch layer of horticulture charcoal to sweeten the soil and keep the roots from rotting. Finally, add two to three inches of good potting soil.

If planting a desert garden with cactus, mix together equal parts of builder's sand and potting soil, because these plants need fast drainage.

Before planting, arrange the plants outside of the terrarium to get a feel for how they'll look.

If you'll see the terrarium from only one side, slope the soil upward toward the back of the container. Place the larger plants in the back and the smaller ones in front. If you want to view it from all sides, place taller plants in the center and smaller ones around them.

Dig a suitable hole with your planting tool. Next, shake the soil from the plant's root system, roll up the leaves one behind the other and lower the plants through the neck of the container with the roots going in first. If you are working with a larger opening, you won't need to roll up the leaves. If you must remove plants, purchase a "pick-up" tool, to do the job.

If you want to add something such as decorative mulch, use the funnel to direct the mulch to the precise places. You'll use the pruning tool to remove unwanted or misdirected plant parts.

Maintaining: Terrariums do best with indirect light.

Water them sparingly. Those with small or completely enclosed openings need only a few drops of water every three to six months. Those with larger openings need more. If drops of water form inside the container, it's getting plenty of moisture. We call this the rain cycle.

You don't need to feed your terrarium plants because you want them to grow very slowly.

Linn Mills writes a garden column each Sunday. You can reach him at linn.mills@springspreserve.org or call him at 822-7754.