Adiantum tenerum

Botanical Name — Adiantum tenerum

Common Name — Brittle maidenhair fern

Plant Family — Pteridaceae

Background

Brittle maidenhair ferns are native to the forests of southern North America, Central and South America along with parts of the West Indies. In the wild they grow on the edges of woodlands and in shady rock crevices or along the sides of streams. At home these ferns do best in moist, organically rich soil, very high humidity and warm temperatures. The genera, Adiantum comes from the Greek word adiantos meaning “unwetted”, and refers to the plants water repellent foliage. This plant spreads by creeping, branching rhizomes forming large colonies over time.

Growth Requirements

Sun

These ferns grow best in bright, filtered sun or light shade. Place in a spot that gets indirect morning or afternoon sun. A north or east facing window would be a great place.

Temperature/ Humidity

This plant requires tropical conditions. High humidity and warm temperatures are essential. A brightly lit bathroom would be an great location.
It’s also important to keep your fern in a spot where temperatures are consistently above 55°F. Your fern will start to suffer in dramatically fluctuating temperatures or temperatures below 45°F.

Water

Keep soil evenly moist, but not soggy. Water when the very top of the soil feels dry to the touch. For a 6 inch sized pot, this should be about every 2 to 3 days. In very warm conditions it could be as often as every day or every other day.

Soil/Roots

Ferns like a rich soil, that is moisture-retentive, yet well-drained.
A good quality potting soil, supplemented with coco coir and compost is an excellent medium that will provide fertile, adequately moist soil.

Flowering

Ferns reproduce by spores, and therefore don’t produce any flowers.

Fertilization

Fertilization for these plants is generally not necessary, but if you choose to fertilize feed your fern once every two weeks with a water-soluble fertilizer diluted at half the recommended strength. Ferns love fish emulsion.

Propagation

The easiest way to propagate these plants is by division. Using a clean, sharp knife or gardening spade, divide the roots into smaller sections, with two or three healthy fronds each. Plant each piece into its own pot and water thoroughly.

Health

Diseases

Because these plants like moisture and high humidity, gray mold and other types of fungal infections are a concern. Prune away any unhealthy fronds and treat with a fungicide for plants. If mold is found in the soil prune away any affected roots and repot the plant in a clean pot using fresh soil.
Aphids, mealy bugs, and scale are attracted to these plants. To treat, wipe leaves with rubbing alcohol or neem oil.
If infestation is especially bad, washing the foliage with a gentle soap is known to be effective. Be sure to rinse thoroughly.

Maintenance (pruning, legginess, repotting)

Repot when the plant is rootbound, and only during the spring and summer. These will do best in a plastic or glazed clay pot. Clay alone would wick away moisture and leave the soil prone to dryness.
Even in the most ideal conditions, lower fronds will brown and eventually die. Pruning these away will allow the plant to dedicate energy to producing new growth.

Toxicity