How to Grow Ferns in a Terrarium

Like many plants, the normal home environment is not humid enough for ferns. The best way to give ferns the proper humidity indoors is to grow them in a terrarium. Ferns also have unusually high moisture requirements, which makes them a perfect terrarium plant because terrariums trap in moisture as well as humidity.

Difficulty: Easy

Instructions

1. Grow ferns in a terrarium in a well balanced potting mix. The potting mix must be mostly compost, but also contain a little peat moss and a little perlite. As with all terrariums, you should use a sterile potting mix. Sterile potting mix can be purchased at greenhouses and many gardening centers.

2. Water ferns in a terrarium only when the potting mix begins to dry out. Ferns need high moisture, but because the terrarium traps in moisture and you'll not be doing anything to improve drainage, the potting mix may take a month of longer to begin to dry out.

3. Use a fine mist to water ferns. Spray the mist onto the fronds and then saturate the potting mix with the mist. Ferns loose a lot of water out of their fronds, so you do need to give them more water at a time than other plants in a terrarium. However, you should stop watering before puddles build up.

4. Remove the terrarium lid when fog builds up. Terrariums tend to fog over when the humidity inside reaches a high point. Because ferns loose so much water from their fronds, this is especially true with ferns. When this happens, just remove the lid for a day and then replace it.

5. Place the terrarium in low to medium light. Ferns will tolerate shade, but thrive in medium light. In a terrarium they will not tolerate direct sunlight.

6. Control pests in the terrarium. Terrariums are susceptible to many insects. Keep a close watch on the ferns for any signs of infestation. Many pesticides will burn a fern's fronds, so control pests by spraying slightly soapy water onto the plants.

Tips & Warnings

• Rotate the terrarium once a week. Fern's fronds move toward light very quickly, so this is necessary to keep shapely ferns.
• Spiders are a great way to control pests in a terrarium without pesticide. They feed on decaying foliage and insects, but do not harm ferns.
• Avoid fertilizing ferns in a terrarium. Most terrarium plants seldom need fertilizer, and ferns need even less fertilizer than most plants.