Mabuse's Fern FAQ (Frequently Asked Questions)
Do ferns grow in the dark?
Many fern species adapt well to indoor circumstances. Popular examples are Davallia and Nephrolepis (the famous "Boston Fern") who are beautiful indoor plants. Their success began with the invention of the Wardian Case, invented by Nathaniel Bagshaw Ward, that resembles a modern terrarium and provides constant humidity. Besides that, temperature and lighting are other main topics to care about.
Often ferns prefer a shady environment. If your home has a garden, ferns will be the natural choice for plants growing under a tree or behind the house in a shady place without direct sunlight. In your home things become a little bit more complicated. A normal lit room that has no direct sunlight might be too dark while direct sunlight, even when it's filtered by the window grate, is much too bright. Depending on the species, there is a minimum of approx. 200 - 300 Lux [6] at the bottom and approx. 2000 Lux for light-loving plants that don't want direct sunlight. (If this sounds too technical for you, we recommend our DIY section.) That means, if placed too shady, your fern won't feel well. Sunshine at morning or in the evening in many cases is okay, sunshine at noon will burn most ferns immediately. If you have a window on the north side of your house, many ferns will feel fine here. If the sun shines through the window, put your fern at a place where the sun doesn't touch it directly.
Do ferns need plenty of water?
As any other plants, ferns need a certain amount of humidity. While tropical ferns demand constant watering all year long we keep hardy ferns on the rather dry side during the winter. Watering a fern isn't much more complicated than watering a flower plant. Some species need moist to wet soil (Blechnum), others will do with less than that (Asplenium / Bird's nest fern, Phlebodium), some will even need less water (Pellaea) and Platyceria just want to get a dunking once a week. This all depends from various environmental influences: if your fern is placed in a shady and cool situation it will need less water than during the summer because light, temperature and plant growth demand different watering. If you are not sure how much water your fern needs, put a finger on the soil. If it feels dry, water your fern immediately. If it feels soggy, wait some time, because this is too wet. If it feels just wet, this is okay for many ferns. If your soil starts to molder, remove the mould. In most cases, it won't hurt your plant but it doesn't smell well and may pollute your air at home. Avoid waterlogging or the roots will rot! After watering your plants, you should wait an hour and then remove water that's still in the bottom plate of the tub.
Talking about humidity, you should make sure that there's enough air moisture. Buy yourself a hygrometer: 40%-60% humidity are okay. Kitchen and bathroom are first choice places for ferns. To support humidity you should group the plants together and spray them with water from time to time (exceptions: Blechnum Gibbum and Platycerium don't like this).
In hotter parts of this planet (desert areas of America), the resurrect fern (Selaginella Lepidophylla), a fern ally that grows in low rainfall areas on dry ledges and is a curled brown ball of stems and leaves for the most of the year. After rain the stems and leaves open and re-green. [7]
Are ferns poisonous?
This is true for Bracken fern (Brake fern, Pteridium aquilinum), the "Lucrecia Borgia of ferns" [8]. Especially the fiddleheads of Bracken are highly toxic and may cause bellyaches, various blood diseases and would be harmful to cattle and horses. Carcinogenicity of Bracken has been demonstrated in laboratory tests [9].
The toxin in Bracken is thiaminase, an enzyme that destroys thiamine (vitamin B1). For horses and swines, loss of vitamin B1 causes myelin degeneration of peripheral nerves. Ruminants suffer from ptaquiloside, another Bracken toxin that affects bone marrow. Hemorrhagic syndromes may occur if they graze bracken for one to two months.
For insects, it gets even worse: if an insect's mandibles tears into the young fronds, the release hydrogen cyanide. Usually this will kill the bug. If not, then a hormone cocktail of ecdysones will cause uncontrolled molting of the insect. [10]
In Japan and arabic countries, Bracken is a special treat, especially the young fronds. Since its poisonous nature, Bracken is not safe for consumption! [11]
Are ferns older than dinos?
Ferns were the dominating plants of the Carboniferous (360 - 290 million years ago) and Permian (290 - 250 million years ago). Though these early ferns resembled the tree ferns of our days, there is no direct relationship between them. Most fern groups of Palaeozoic are extinct, but two groups (Marattiales and Osmundales) are still existing today. Most extant ferns belong to groups that evolved in the Mesozoic (195 - 136 million years ago), the most successful fern group of our days (Polypodiaceae) dates from the Late Cretaceous (136 - 63 million years ago) and is much younger. [8], [12]
Where are the little ferns coming from?
There are various ways ferns use for propagation. Some species use perennial rootstocks, creeping beneath the surface and then outgrowing. Others grow bulblets or their fronds bend over to the earth and root at the tip. Boston ferns grow stolons that try to reach out for new ground, other ferns produce plantlets directly on their fronds.
The existence of fern spores kept unknown for long times. People thought of ferns having invisible blossoms, flourishing in the dark during one night in a year. The truth is even more mysterious. Instead of seeds fern produce spores: small bodies that emerge from spore capsules on the fronds and that are taken away by the wind (This is one reason why ferns are pioneer plants. Fern spores are almost everywhere.) Once a spore falls on suitable ground it germinates, producing a small heart-shaped plantlet: the prothallium (or prothallus). On its under surface it develops root hairs and two sorts of reproductive organs: male (antheridia) and female ones (archegonia). The antheridia release small, spiral cells (antherozoids) that move through the watery film on the prothallium, trying to find an archegonium and the oosphere (egg cell) in it in order to fertilize that cell. Antherozoids may travel several meters until they find their goal (or get lost). In most cases, the archegonium will be on the same cell. Sometimes it may be on a different cell, thus enabling gene exchange between individuals of the same or different species. After fertilization the first leaf unfolds and the sporophyte, the new fern, emerges. The prothallium isn't needed any longer and withers away.
Is it possible to grow outdoor ferns indoors?
Depends. We're still experimenting. We've got four Dryopteris that are deciduous and lost nearly all fronds during winter. Two of them are still hibernating, while the other two are already developing new fronds. Maintaining outdoor ferns indoors is possible, but a pot just filled with soil and a sleeping rhizome during the winter isn't neccessarily an impressive sight. We put them in a cold, well-lit room and watered them sparingly (just as much not to let the soil dry out). If you bought your ferns from a nursery there might be a risk of pests overwintering in the soil. So care has to be taken that young fronds coming up in the spring won't be accompanied by caterpillars and snails. Another possible problem could be the size of outdoor ferns: some get pretty big and you should give them enough room. If you have a garden, put them outside.