The Giant Staghorn Fern or capa de Leon (Platycerium grande) can be propagated deliberately from spores even without following the advanced, but meticulous, procedure in fern spore propagation. The latter involves the sowing of mature spores on sterilized fragments of “cabo-negro” or “paslak” and maintaining humid condition all throughout until germination and seedling emergence. Mass propagation by spore can also be done through tissue culture.
Cabo-negro is a local term for the indigenous, black, trunk-like columnar plant organ probably consisting of the root of a giant terrestrial fern.
It was only by accident that we discovered that the Giant Staghorn can be mass produced sustainably by exploiting its natural method of propagation. We’ve had several large Giant Staghorn ferns in the backyard at General Santos City since about 40 years ago, but we always grow these from starter plantlets or juvenile ferns which we bought from private suppliers. Until recently, the city had a hot climate with scarce rainfall.
Then one day about a year ago, my mother Mama Maxi noticed plantlets, with only overlapping basal fronds, growing from a lone, upright cabo-negro which has been used as support for epiphytic orchids for several years. It stands about 5 meters away from a huge Giant Staghorn which clasped the trunk of a Fishtail Palm. The cabonegro was regularly sprinkled with tap water. The Staghorn itself regularly produced spores from the underside of its foliar frond.
My mother taught us the basics of gardening. At 74, she still tends the various ornamental crops, seedlings and vegetables in the backyard. She extracted the fern plantlets from the cabonegro with the help of a knife, including a segment of the cabonegro which held the roots of the fern. She then attached it to a segment of a coconut husk.
1. Harvesting of spores. We harvest the mature spores by scraping those “browns” from the underside of the foliar fronds, placing them in a brown envelope, and allowing them to dry by air drying. Otherwise, we cut the spore-containing frond, divide it into smaller segments, insert the segments in a paper envelope, and dry them by exposing the envelope to full sun. The dry spores can be placed in a closed glass jar or plastic canister and stored under refrigeration.
2. Sowing of spores and care. We dusted the dried spores on the sides of the same standing cabo-negro. The cabo-negro is kept moist by regular watering. Care of the sown spores and plantlets, therefore, becomes incidental to the management of orchids which adhere to the cabo-negro.
3. Extraction of fern plantlets. As soon as it becomes visibly certain that the green growth belongs to the Giant Staghorn Fern but preferably when the plantlet reaches a horizontal width of about 4-5 cm, we extract it from the cabo-negro with the use of a chisel, including a segment of the latter which hold the base of the plantlet.
4. Transplanting of fern plantlets. The propagule (plantlet + cabonegro segment) is immediately immersed in water, pressed on a small piece of a decomposing coconut husk, and attached to the surface of a slab of coconut trunk (we use rejects) or wood lumber or split bamboo. The coconut segment (or substitute) is then inserted in a plastic bag. The bag is closed tightly and kept under shade for at least 7 days. This is an application of the “bukot” or “kulob” system which ensures that the plant is kept under high humidity, a condition which favors healing from shock and root development.
5. Care and management. After at least 7 days, the plastic bag is removed. The slab with attached propagule is hang under partial shade and tended intensively.
Disclaimer: We are not promoting the harvesting and trading of cabonegro. We are in fact experimenting on other possible growth media for fern spore germination and growth.