This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
As soon as the first little true frond or two are seen above the thin semi-translucent prothallus (see p. 213) the young Ferns will be ready for pricking out. For this purpose 5-in. pots, or shallow cutting boxes, are filled with the Fern compost already described, and one, two, or three little plants are lifted with the point of a penknife, or a stick, and gently pressed into the soil. The little plants are afterwards carefully watered and kept in shaded spots. They grow freely if the temperature is kept up to about 65° to 75° F. at night, and in a few weeks are ready for transferring into 2½-in. or 3-in. pots singly, or two or three together in a 5-in. pot.
This method of raising Ferns from spores applies to almost every species and variety. In practice, however, it is found more convenient with some of the Aspleniums, like bulbiferum, biforme, etc, to detach the plantlets or bulbils on the fronds and treat them exactly in the same way as the young Ferns raised from spores. Most of the Nephrolepis are propagated by means of the stolons or runners that are freely produced. In this work only the most remunerative kinds of Ferns are alluded to. Readers interested in others are recommended to consult The Gardeners Assistant.