Fern is a division of vascular plants that have roots, stems and complex leaves. Ferns reproduce by spores and don’t have seeds or flowers. Today ferns became a plant of interest due to the popularity of the varieties of Boston Fern which is a very common houseplant.
Greenhouse growers couldn’t stay away, especially if you are a fan of Victorian times when ferns were grown in large numbers and were a must have in any conservatory. Although today majority of gardeners use a couple of ferns as background plants between flowers, other growers dedicate a whole greenhouse for large specimens.
You can either grow ferns in pots or hanging baskets, however they have special needs. You can also grow them in ground, so make up your mind about container growing. These special needs are high humidity, shade from direct sunlight and moist compost during the growing season. The best orientation for growing ferns is an east or north facing greenhouse structure.
Ferns are perfect plants to grow in a greenhouse because almost all the popular types can grow in the temperatures ranging from 50° to 80°F. So you can keep them in an unheated greenhouse. However, most ferns require high air humidity.
What are the best ferns to grow in a greenhouse?
Adiantum (Maidenhair Fern)
These ferns consist of filmy leaflets on wiry stems. The leaves are long and delicate. It is also known as Venus hair fern and originally comes from the tropical regions. In wild Maidenhair Ferns grow on rocks around waterfalls, so they really like moisture.
Adiantum raddianum is a perfect fern for greenhouse growing as it thrives in humid environment. It is a very robust plant which grows to 1 ft in height. The stem is black and leaves are fan-shaped. It also prefers bright indirect light.
It is a genus of approximately 700 species of ferns. Asplenium nidus and several similar species are well-known as Bird’s Nest Fern. They are characterized by 2 ft long spear-like leaves that surround the fibrous nest at the center.
The second common species in cultivation is Asplenium bulbiferum also called spleenwort or Mother Fern. This plant has feathery fronds (large, divided leaves) that bear numerous tiny plantlets once mature. All Asplenium ferns like shade and moist environment.
The popular species for greenhouse growing is Blechnum gibbum which is known as hard fern or Silver Lady. It is a large fern with a crown of palm-like stiff fronds. This plant needs space as when mature it will be 3 ft high with a 3-5 ft spread.
Another species you can grow is Blechnum brasiliense that has larger fronds which can reach up to 4 ft. B. brasiliense ‘Volcano’ is an interesting find as it has reddish green fronds. To thrive this fern needs higher temperature, so you would need to run a heater in a cool greenhouse.
Davallia (Rabbit’s Foot Fern)
It is a genus with about 40 species of ferns. Davallia fejeensis or Rabbit’s Foot Fern or Hare’s Foot Fern gets its name because of the furry creeping rhizome which grows over the surface of the compost and down the side of the pot.
Wiry stems carry the fronds which consist of tiny leaflets. The most popular species for greenhouse growing is Davallia canariensis with Carrot-like leaves. It is growing well in dry and sunny atmosphere in comparison to other ferns.
Dicksonia (Tree Fern)
It is a genus of tree ferns that originate from eastern Australia. Dicksonia is the most widely available tree fern. Dicksonia antarctica commonly called Tasmanian Tree Fern or soft tree fern grows outdoors in mild areas, but in a greenhouse or conservatory it can reach 15 feet tall with a possible 6-10′ spread.
Nephrolepis (Boston Fern)
It is a genus of approximately 30 species. In Victorian times it was popular to grow varieties Nephrolepis exaltata and Nerphrolepis cordifolia because of their stiff leaves. Today, Nephrolepis exaltata ‘Bostoniensis’ commonly called Boston Fern or sword fern is the most popular fern to grow in a greenhouse and in homes.
All Boston Fern types are easy to care for and they look incredible in hanging baskets. Boston fern has attractive, erect fronds. Other cultivars that you can grow in a greenhouse are ‘Fluffy Ruffles’ with feathery leaflets and ‘Whitmanii’ with lacy leaflets.
Pellaea (Button Fern)
Ferns of genus Pellaea have bluish-gray stems and members of the genus are commonly called cliffbrakes. Variety Pellaea rotundifolia known as Button Fern has a creeping rootstock which produces 1 ft long fronds. Round, leathery leaflets make up these fronds. This fern is growing low, so the main use is to cover the ground or to keep it in hanging basket.
Platycerium (Staghorn Fern)
Platycerium genus comprises 19 varieties and are also widely known as staghorn or elkhorn ferns because of their uniquely shaped fronds. For example, Platycerium bifurcatum or Staghorn fern has large fronds – one flat and clasping and 3 ft long fertile fronds, which bear spores, that are anter-like and spreading.
It is an epiphytic fern meaning that in wild it grows on a tree bark. So in a greenhouse you can grow it in a shallow pot or cover the root ball with sphagnum moss and attach a piece of log with wire. You would need to immerse Staghorn fern in water for a few minutes every week.
Polypodium (Hare-Foot Fern)
The hare-foot fern or golden polypody is native to tropical regions but is distributed worldwide. The common variety, Polypodium vulgare, is a large plant with thick creeping rhizome which grows in dry air. Another variety – Phlebodium aureum has 2 ft long deeply-divided fronds.
Phlebodium aureum is a tender plant so can be grow indoors only. The best variety for greenhouse growing is ‘Mandaianum’ as it has bluish-green leaflets that look fascinating in a greenhouse. It can grow up to 5 ft with large and wide fronds.
Polystichum (Soft Shield Fern)
Polystichum is a genus with several species that don’t look similar to each other. The most popular is Cyrtomium falcatum ‘Rochfordianum’ also known as Rochford’s Japanese Holly Fern. Fronds consist of dark green and glossy holly-shaped leaflets. This fern can grow in a dry atmosphere.
Pteris (Table Fern)
Pteris is a genus with around 300 species, however, most of them are easy to grow. The fronds come in a range of shapes and sizes. The most popular varieties are Pteris cretica or Table Fern and Pteris ensiformis or Silver Lace Fern.
Table Fern is an evergreen fern originating from Europe, Asia and Africa. You can find it in a variety of colors and forms. Pteris ensiformis has a silver band along the midrib, that is why it is called Silver Lace Fern or sword brake fern.