If you've ever grown (or killed) a maidenhair fern, you'll know that these delicate, lacy beauties are quite picky when it comes to their growing conditions. We've featured plenty of tough-as-nails plants (spider plants, Chinese evergreens, cast-iron plants, and dracaena) that can tolerate a wide range of conditions, but maidenhair ferns are the opposite. As long as you know that there's no fooling around when it comes to meeting its needs, though, this fern will reward you with gorgeous foliage. Here is what you need to know to keep a maidenhair fern thriving.
About This Plant
The name maidenhair fern actually refers to the Adiantum genus of about 200 different species that grow around the world, everywhere from New Zealand to the Andes. Many varieties are especially suited to growing on rock walls around waterfalls, where the water seepage and moisture in the air keeps them from drying out. Although there are species that live in a variety of conditions outdoors, I'll be talking about the conditions that generally suit varieties commonly kept as houseplants.
The ASPCA doesn't have a listing for maidenhair ferns, but the general consensus is that like most ferns, they're non-toxic to dogs and cats.
Where to Grow
From temperature, to water, to sunlight, maidenhair ferns are divas in every way. Direct sun will lead to scorching, but too little light will cause poor growth and yellowing fronds. If possible, place in a location that gets indirect morning or afternoon sun, such as a northern window, with no drafts. A temperature of about 70°F (21°C) is ideal, but temperatures below 60°F (16°C) should be avoided. Maidenhair ferns can't tolerate dry air, so if your home is dry, you'll need to figure out how to provide your plant the humidity it needs. I've had the best luck keeping mine in the bathroom, near a shower, but giving it regular misting allowed it to thrive in another location. You can also increase the humidity near your plant by standing it on a water-filled pebble tray, or it may do well in a closed terrarium environment or under a glass cloche (but be extra careful to avoid direct sunlight in these situations.)
Care and Planting
Due to the importance of moisture for this plant, it's best to plant it in a plastic pot with drainage holes, or keep it in the plastic pot that it came in, and place this in a more attractive outer cachepot. Clay pots alone aren't recommended because they allow the soil to dry out too quickly. And when the soil dries out, the fronds shrivel up and die immediately. This is not a plant you can be lackadaisical about watering, because you also cannot let the roots sit in puddled water. The soil needs to be kept constantly moist, but not soggy.
From killing a few, and then successfully growing a few, I can tell you what has worked for me. Mine are in plastic pots, inside a cachepot. Every few days I take the plastic pot out, and thoroughly water the plant in the sink. I let the water drip out until it stops, then I put it back in the cachepot. (Ease-of-watering is another reason why a bathroom is an ideal location for this plant.) If your maidenhair fern dries out and its fronds turn brown and die, there may still be hope. Cut the fronds off at soil level, and keep the soil moist. The plant may re-grow after a few months. Even under the best conditions, your plant will end up with dead leaves and fronds. Regularly trim these away at soil level. Fertilize monthly year-round with a half-strength liquid fertilizer. It's best to only repot when your plant is root-bound, and preferably in the spring. Repot in a rich, high quality soil, such as a potting soil amended with 25% compost.
How to Propagate
When repotting, use a clean knife or sharp spade to divide the roots into pieces containing a minimum of two to three healthy fronds each. Plant each section in its own pot, and water well.