Tips for Growing Fern Plants

Ferns - In the Garden and Indoors

Polystichum setiferum 'Divisilobum Group' (Soft shield fern), evergreen fern against a wall
Dorling Kindersley/Getty Images

Ferns are some of the most beautiful plants in a woodland, but they can grow equally well in your garden or even your home. The term "fern" refers to any of about 12,000 species of plants that do not produce flowers or seeds, instead reproducing by spores. Not all 12,000 fern plants are suitable as garden plants, but the selection is still quite large.

Ferns have been in existence for over 300 million years. Many ferns are easily recognizable because of their fronds, or lace-like leaves. However, there are many different species of ferns growing around the world, in a variety of habitats and fronds can range in size from less than an inch to well over 12 feet.

To be successful growing ferns, whether in your garden or indoors, you will need to know something about the variety of fern you have and its preferences. Here are tips for growing and caring for some of the more popularly grown fern varieties.

Sun Exposure for Ferns

While most ferns prefer a shady location, they don't do well in deep shade, The dabbled shade provided by tree branches makes a better choice. Think about how they grow in the forest and try and find similar conditions in your yard.

Ferns can handle some direct sunlight, however, the more sun they get, the more moisture they will need. Few ferns will tolerate dry, hot, sunny locations.

Growing Ferns from Spores

Ferns do not produce seeds, they are grown from spores. Spores look like small dots on the undersides of the fronds. Fern plants can drop millions of spores onto the ground, but only the few that find ideal conditions will grow. If you would like to try growing ferns from spores, you can collect them and plant them just as you would seeds.

To collect fern spores, wait until they darken and start to fall off the fronds, signaling they are ripe. An easy way to do this is to cut off a frond when its spores are beginning to darken in color. Leave the frond in an open paper bag or on top of a piece of paper (indoors, where the spores won't get blown away) and wait for the spores to fall. You want to be sure they are fully mature and fall off on their own.

Planting Ferns from Spores

  1. Fern spores are quite small and can be difficult to work with. Keep them on the paper or in the paper bag until you are ready to plant them.
  2. Fill a flat or another container with sterile, moistened potting mix. Shake the spores off the paper or bag directly on top of the mix and press gently, so the spores make good contact with the soil.
  3. Mist the surface of the potting mix, to moisten the spores and keep them in place.
  4. Cover the container with plastic and place it in a tray filled with 1 - 2 inches of water. Move to a warm spot, with indirect sunlight.
  5. Keep replacing the water in the tray until you see signs of growth. This can take 6 - 12 weeks, so be patient and don't let the soil dry out.
  6. The first thing you will see will be small heart-shaped shoots called prothalli. These can be gently lifted out of the container and moved into individual pots filled with damp, sterile potting mix.
  7. Leave the transplants uncovered, but keep them moist.
  8. Once the prothalli begin developing fronds, they can be slowly hardened off and transplanted outdoors.

    Planting Ferns from Stolons

    You may notice long, fuzzy string-like things growing from your fern. These are stolons or runners, and you can propagate more ferns by layering them on the soil.

    Pin the stolen to the nearby soil with a U-shaped landscape staple or a small rock. Keep moist and in a few weeks the stolon should root and send up new growth. When that happens, cut the stolen from the mother plant. The new plant can be transplanted at this point.

    Growing Ferns Indoors

    Ferns make lovely houseplants, but the humidity in homes is often too low for some ferns to thrive. This is especially true in the winter when the heat is on. Misting the plants will help improve humidity levels as will sitting their containers on a tray filled with pebbles and just enough water to reach the bottom of the fern's pot.

    Some ferns that can better handle low humidity include:

    Dividing Fern Plants

    Fern plants divide much like other perennial plants.

    1. The best time to divide ferns is in early spring when they are just resuming growth.
    2. Make sure the fern plant has been well watered either the day before or at least several hours before dividing.
    3. Lift the fern and pull or slice the root ball into 2 - 3 pieces, depending on the size of the existing plant. Each piece should have a least 1 growing tip where the fronds are sprouting.
    4. Transplant as soon as possible and water well. Be sure to keep the new transplants moist, until new growth is seen.

    Caring for Fern Plants

    Watering: Ferns prefer a moist location, but they can handle a brief dry period. They will slow in growth and may turn a bit brown, but they should come back when the dry spell ends.

    Mulching: The best mulch for ferns is leaf mold or finely shredded leaves. This mimics the conditions they would have grown on a forest floor and helps to retain the moisture they need. Add a new layer of mulch each spring.

    Weeding: Ferns tend to be shallow rooted. Be careful cultivating around them, especially in the spring, when the tiny fiddleheads are first emerging.

    Feeding: Most ferns do not need supplemental fertilizer. Adding some compost to the original planting hole and following up with side dressings of leaf mold mulch should be enough for them.

    Winter Care: Don't cut back ferns in the fall. Leave the fronds as protection for the crowns of the plants. You can clean up old, dead fronds in the early spring when the fiddleheads appear.