The maidenhair fern, Adiantum, a genus of roughly 250 fern species belongs to the subfamily Vittarioideae in the Pteridaceae family, although some place the genus in the Adiantaceae family. The name means “unwetted” in Greek, alluding to the ferns’ ability to shed water without getting wet.
These ferns are 12 –24 inches high and 12 –24 inches wide, with a distinctive lace-like appearance, bearing dark, frequently black stalks and stems, very small fronds, and delicate fan-shaped bright green leaves. They’re considered to be hardy ferns, unlike other ferns that prefer humid conditions, but don’t let this deceive you – they are somewhat difficult to grow indoors, as they’re very particular about their environmental conditions.
These ferns are often found growing naturally in locations where other plants rarely do, like in rock clefts and rock walls, surviving on water seepage. They commonly prefer moist, well-drained, and humus-rich locations, from vertical rock walls to bottomland soils to rock walls near water seepages and waterfalls. These ferns thrive when planted outdoors in zones similar to their native habitats.
Although they are stunning through all stages of their growth, these ferns are slow-growers, usually taking almost three years to become fully mature.
Most species are indigenous to the Andes although some are also found elsewhere in the world, with nearly 40 species found in China, a few from North America, New Zealand, including a few tropical species. This popular species is cultivated by many growers in the horticultural business.
These ferns are generally found growing in natural environments below tree canopies that provide them with partial sunlight and shade, you will have to try to mimic these conditions to successfully cultivate the ferns indoors.
Find an area indoors that only gets indirect sunlight. Harsh lighting or direct sun should be avoided since their delicate leaves can get burnt very easily. However, insufficient light will lead to leaves turning yellow and poor growth. Ideally, try to look for a spot that has indirect sunlight in the morning or afternoon.
Moisture is important for this thirsty fern and it requires consistently moist soil to thrive. Water the fern regularly, either daily or every second day, never permitting the soil to become dry. However, over-watering might make the leaves turn yellow. Do not allow the fern’s roots to get water-logged, so good drainage is essential to prevent root rot.
You can grow the fern in a container with good drainage capacity, placing it in another outer container with no drainage holes and filled with pebbles at the bottom to collect excess water – this will also help raise humidity levels.
This will enable you to easily check moisture levels, with the drainage holes preventing the soil from getting too soggy. When watering, just lift the pot, hold it over a sink, and water it. Wait until water stops draining out. Before replacing the potted fern inside the cachepot, remove any excess water from the cachepot.
These ferns require warm, humid air to survive and thrive – this is the most significant environmental element in caring for these ferns successfully and often very challenging to achieve indoors, to copy their natural environmental conditions, you can mist them twice a day, place them near a humidifier and keep a humidity tray nearby to maintain proper moisture levels on the delicate leaves – you can use all 3 methods as well since these ferns love moisture on their leaves.
Alternatively, you could also house the ferns in a humidity-rich room indoors, like your bathroom or in a greenhouse but be extra careful – these divas don’t like cold drafts.
These ferns are best kept in temperatures above 70°F and should not be kept in any area indoors where temperatures drop below 60°F.
They prefer to grow in a well-draining growing medium that still retains some moisture as mentioned above, water is very essential for these ferns, so create the proper environmental conditions by adding moss or any organic matter such as peat or compost to the soil to help it retain water without getting soggy.
These ferns are generally slow-growers and typically take up to 3 years to become mature, which means that they don’t have to be repotted very often. They can be repotted after they become mature, depending on the container size and their growth rate.
They don’t mind getting slightly crowded, so don’t hurry to repot them if you’re not sure, some care has to be taken while doing this to avoid damaging their delicate fronds. Repotting them successfully also includes dividing and propagating them, as described below.
When you are repotting, use a knife or sharp blade or your hands to split the delicate root ball into several more manageable sections, each section possessing 2 – 3 healthy fronds. Plant each separated section into individual pots and water well. Repotted ferns should not be fertilized straight away, as their roots might get burned.
It isn’t necessary to fertilize these ferns, as they will grow fine without feeding; however, if you think they need extra nutrients, a monthly application of a diluted balanced fertilizer will be sufficient. Avoid fertilizers with excess nitrogen as this could cause leaf burn and do not over-fertilize.
Pruning is not necessary other than removing dead leaves or fronds.
Only a few common insects find these ferns tasty. Mealybugs and scale can attach themselves to the fronds and cause some damage. Check the plants frequently and treat infestations with insecticidal soap.
The small leaves of these ferns are very delicate and sensitive. The plants have to be located in a good spot or their leaves will tell you if they are not placed well. These plants need lots of moisture and humidity and if the air is dry, the leaves will either dry up and/or brown at the tips, curl up or drop off. Removing dried-up, browned, or curled leaves will also help the foliage grow thicker.