How to Grow and Care for Maidenhair Fern Indoors

Maidenhair ferns have delicate fan-shaped leaf segments, typically clustered on wiry black stems, and their leaves are smaller than other types of ferns. In addition to being one of the most popular fern houseplants, the maidenhair fern can also be found in nature, growing in places where other plants typically don't, like on rock walls and in between rock fissures where the moisture from water seepage keeps them alive. Though they are visually stunning throughout all stages of their growth, they are considered a slow-growing fern, typically taking up to three years to reach their full mature size. Plant the fern outdoors any time during the year if you live in the right USDA zone where they'll thrive.

Common Name	Maidenhair fern, Delta maidenhair fern
Botanical Name	Adiantum raddianum
Family	Pteridaceae
Plant Type	Fern
Mature Size	1–2 ft. tall, 1–2 ft. wide
Sun Exposure	Partial sun, shade
Soil Type	Moist but well-drained
Soil pH	Neutral
Bloom Time	Non-flowering
Flower Color	None
Hardiness Zones	10-11 (USDA)
Native Area	North America

Maidenhair Fern Care

Maidenhair fern is part of the Adiantum genus that includes over 200 varieties of ferns grown around the world. The genus name is derived from the Greek word adiantos, which means "unwetted"—an apt description for the fern since its leaves repel water.

Maidenhair ferns are delicate plants with very small fronds and a lace-like appearance. They're considered hardy ferns, rather than ferns preferring steamier conditions, but don't let the description fool you. Maidenhair ferns can be difficult to keep healthy indoors, as they're quite particular about their growing conditions. The most important environmental factor when it comes to caring for this fern with success is humidity—it thrives on moisture and needs a lot to survive, which can often be difficult to achieve in indoor environments.

Light

In their natural forest environment, maidenhair ferns are primarily covered by a canopy of trees, receiving a bit of shade and partial sunlight. To successfully grow the fern indoors, try and mimic these conditions by finding a spot in your home that receives indirect sunlight only. Avoid harsh light or direct rays, as the delicate leaves of the maidenhair fern can burn very easily. However, too little light leads to poor growth and yellowing fronds. Try to find a spot that receives indirect morning or afternoon sun, like a northern window. But be careful: this prima donna dislikes cold drafts!

Soil

Maidenhair ferns prefer moist but well-draining potting soil. As mentioned, water is very important to this fern, so up your chances of creating the proper environment for it by incorporating moss or an organic matter like compost into the soil to help it to retain water.

Water

Your best bet to ensure that your thirsty maidenhair fern thrives is to focus on giving it multiple water sources. Consistently moist soil is a great place to start—from there, be sure to water your fern regularly, either daily or every other day, never allowing the soil to dry out. Watch for yellow leaves that may occur from overwatering. Do not let the plant's roots stand in water. Moisture is vital--but drainage is important to avoid root rot.

Keep the fern in a plastic pot with holes, then place that plastic pot in a more attractive outer pot if you wish. This way, you can easily check on the moisture levels in the plastic pot, and the drainage holes will prevent the soil from becoming too soggy. To water, simply remove the plastic pot from the cache pot, water the plant over a sink until the water stops draining from the plastic pot, then replace in the cache pot.

Temperature and Humidity

This fern requires very warm, humid air. To mimic its ideal conditions, mist the plant with warm water a couple of times a day to maintain the proper moisture levels on its delicate leaves. Alternatively, you can place the potted plant near a humidifier or atop a tray of wet pebbles to increase humidity levels. Also consider housing the plant in a moisture-rich environment at home, such as a bathroom or garden greenhouse.

Temperature-wise, the fern is best kept above 70 degrees Fahrenheit and should not be placed anywhere in your home where the temperature or cold drafts dip below 60 degrees Fahrenheit.

Fertilizer

It's not necessary to fertilize a maidenhair fern, as the plant will do just fine without it. However, if you wish to provide it with an added dose of nutrients, feed with a balanced, diluted blend of fertilizer once a month. Avoid any fertilizer with too much nitrogen (use 200 ppm or less), which can cause the tips of the leaves to burn.

Potting and Repotting Maidenhair Ferns

These ferns can be repotted annually or biannually, depending on the pot size and the plant's growth rate—they don't mind being a little crowded, so don't rush to repot them if you're unsure. Instead, wait for signs that your fern is outgrowing its home, like the roots filling up the pot. To repot a maidenhair fern successfully:

1. Use a clean, sharp knife or spade to divide the roots.
2. Divvy the plant up into more manageable sections, maintaining a minimum of two to three healthy fronds within each division.
3. Plant each section into its own pot, and be sure to water them well.
4. Do not fertilize the repotted ferns right away, as this may burn the roots. 

Common Pests

Only a couple of common insects find indoor maidenhair ferns tasty. Scale and mealybugs like to attach themselves to the fronds. Check the plant regularly and treat any infestation with insecticidal soap.

Common Problems With Maidenhair Ferns

The small leaves of maidenhair ferns are very sensitive. You'll need to find the perfect indoor spot for the plant or the leaves will let you know it's not positioned well. If the air is too dry and the plant needs more moisture and humidity, the leaves will do the following: curl up, dry out at the tips and/or brown at the tips, and fall off.

Additionally, vigilant removal of curled, dried-out, or browned leaves can also help the fern grow denser foliage.