How to Care for a Terrarium

Terrariums are extremely low-maintenance compared to potted plants. If properly constructed, a terrarium will last for about a year with minimal care. A 2001 report from Michael N. Dana of the Purdue University Cooperative Extension Service says that at that point, it's time to redesign the terrarium, after which you'll have another year of low-care greenery to enjoy. A 2007 article from the University of California Cooperative Extension says the first round of watering when you put the terrarium together determines whether the terrarium succeeds or not.

Add water little by little once the terrarium plants and growing media are in place. No matter how much your terrarium plans say to add, do it in very small amounts because you don't want extra water pooling up in the soil. Stop once you see water begin to collect at the bottom of the terrarium.

Replace the cover once you no longer see water droplets on the plants.

Place the terrarium in bright but indirect sunlight. A University of Missouri Extension service report from 2010 says the one exception to this is a dish-style garden containing plants that require bright light. If you don't have an area with bright indirect light, place a 100-watt light or fluorescent bulbs over the garden for 16 to 18 hours each day.

Look for condensation on the plants, and for dry soil. Condensation should form on the inside of the container and eventually run back down into the soil to serve as a water supply. If it forms on the plants instead, then the interior is too moist. Keep the cover off for a time each day until the plants remain dry. The Purdue report says to leave the cover off for several hours, while the UC Cooperative Extension recommends only 10 to 15 minutes. If the soil dries out, add water in small portions and stop if you see it begin to sit and not absorb into the soil.

Remove extra leaves and other parts if a plant begins to get too big for the environment. Pinch them off with your fingers. Remove dead plants if you find any.