Ferns can be the unsung heroes of the garden, given little credit for gracefully filling those awkward corners where little else will grow. Usually hardy, and sometimes evergreen, they have an important role in creating the backbone of the garden planting. They are easily outshone by more colourful and spectacular plants, but few have the same long lasting value as a fern, which will still be there, unchanged, when the dahlias and daturas have stopped flowering.
When an experienced gardener has a plant they love, they will often try to propagate it through trial and error, until they learn to be successful. However, even seasoned horticulturists take fright at the thought at growing ferns from spores. There seems to be a mystique about it, a cloak of mystery, which puts it in the same specialist sphere as skills such as hybridising, grafting and budding. In reality, the skill which is the most important is actually patience, as spores can take weeks or months to germinate and young ferns can grow very slowly.
The first thing you need are … spores ! They are available to buy from specialist growers, some seed suppliers, and fern enthusiast societies. Growing from spores is a very inexpensive way to get lots of new plants, as spores are so tiny that there can be hundreds in a packet. You can also gather your own spores from parent plants in your garden, which means that your new ferns will be free!
Spores are found on the underside of the leaves of mature ferns towards the end of the growing season. They are usually brown or black spheres, adhering to the leaf, and the size varies according to variety. Ensure that the spores are ripe before you gather them, and you can judge this by colour. Spores can be harvested in two main ways, solid leaves can be gently scraped with a round bladed knife, over a sheet of white paper, so that spores fall onto it and can be clearly seen. Finely dissected fern leaves can be sandwiched between 2 sheets of white paper, and left until the spores are visible on the paper, often almost leaving a silhouette of the original leaf. Once the spores are on the paper, it can be gently rolled into a funnel so that the spores can be put into an envelope, ready for sowing.
Once you have obtained your spores, you need a container to grow them in, and anything you would use for sowing seeds will probably be fine. A small seed tray, shallow plant pot, plastic take away container with holes punched in – anything with adequate drainage will do. The chosen container must be really clean and sterile, which means a good wash, followed by sterilisation in boiling water.
The container should then be filled with compost, preferably a fine, sieved potting compost, rather than a more coarse, peat free one. The compost should be filled to leave between 1 – 3 cms below the rim, and carefully levelled. Immediately cover the surface with a sheet of kitchen paper, or a coffee filter, to reduce contamination. Then, boil a kettle and pour it over the compost and paper, to sterilise, before leaving to cool. The cooling process can take a long time, but do wait until the compost is completely cool before sowing the spores.
The spores can then be sprinkled over the surface of the compost. As they are so tiny, sowing can be difficult, and spreading the spores evenly is hard to achieve. Try not to cough or sneeze at this point, and do sow indoors where there is no breeze ! The container of spores should then be labelled and placed straight into a plastic bag, which should be sealed. The spores now have a micro climate which is damp, sterile and ideal for germination. Place it out of direct sunlight, under the greenhouse staging for example … and wait.
And wait … and wait … and wait …
Keep having a sneaky peek every couple of weeks, but try to do it without opening the plastic bag. Hopefully, the first thing you will see is a green film on the surface of the compost. Over time this film will develop into a moss like growth, which grows taller and ‘lumpier’. Do not do as I did, the first time I attempted to grow ferns, and throw the compost away, thinking this was some gross and unwanted moss – this is most likely be the beginning of the growth of prothalli.
Prothalli are a stage in the life cycle of a fern and they resemble a small-leaved moss. Fertilisation has to take place between egg and sperm, at this point, before the ferns can begin to grow. As the sperm travel through water it is important to keep the environment moist, and even mist the prothalli if necessary. Again this process will take some time, and the length of time can vary tremendously.
Once the prothalli develop into small fern plants they can be patched out. Small individual pots should be cleaned thoroughly and filled with compost then watered and allowed to drain before the young ferns are planted out into them. If the ferns are large enough, then it may be possible to transplant them individually, but if they are too small for this, then a patch,or clump, can be potted up at this stage. Drying out is not an option for young fern plants, so each pot should be labelled, then put into a clean, plastic bag and sealed. They should then be placed somewhere cool, away from direct sunlight.
When the small ferns have grown and are filling their small pots, they can be carefully potted on into larger pots. It is at this point that they will no longer be given the protection of the plastic bag, and the loss of this micro climate can be a shock . Misting, or partially covering them can help them to acclimatise to their new environment. Again they should be kept somewhere cool, out of direct sunlight.
Once the young ferns are well established and growing strongly, they can be moved into their final places in the garden.