Psilotum nudum grown in axenic culture by Dean Whittier

Growing Technique #1

The spores should be as fresh as possible and surface sterilized with 20% Clorox. The surface-sterilized spores should be sown on 15ml of nutrient medium in culture tubes having a diameter of 20mm and screw caps which are tightened to reduce moisture loss. They should be kept in normal light conditions for 6 months. The cultures should then be moved to total darkness for 6-12 months. This should result in a high percentage of germination.

Nutrient Medium: The nutrient medium contained a modified Knudson's solution. A liter of medium contained 250mg NH4Cl ; 250mg Na2SO4; 125mg MgSO4; 7H2O; 235 mg CaCl2and 125 mg K2HPO4plus FeEDTA and minor elements. The medium was solidified with 0.7% agar and contained 0.5% sucrose. The medium was adjusted to pH 6.1 prior to autoclaving.

Growing Technique #2

Some people have had luck by mixing the spores into the soil of a potted Hoya or Diffenbachia or other large house plant theat will not be repotted for several years. If everything is right gametophytes occasionally develop after 2-3 years. 

Grape ferns from spore by Dean Whittier

Growing grape ferns from spore in axenic culture.

Dr. Whittier used Botrychium jenmannii but this method or with slight variations may work for other Botrychium species. Dr. Whittier's method is one of the best developed to date.

Suface sterilize the spores with 20% Clorox (Whittier 1973) and sow on 15 ml of nutrient medium in culture tubes screw caps that can be tightened to reduce moisture loss. The cultures should be maintained at 22 degrees Celsius in darkness until after embryos are formed.

Nutrient Medium: A liter of nutrient medium contained 25 mg arginine; 100 mg MgSO4; 40 mg CaCl2; and 100mg K2HPO4. In addition, 8.5 ml of a FeEDTA solution and 0.5 ml of a minor element solution were added per liter. The medium was completed with 0.2% glucose and 0.8% agar and was adjusted to a pH of 6.1.

Spore germination should occur after 5 wks. in the dark producing cultures with numerous gametophytes that are white. If overcrowding occurs either weed some of them out or transfer them to a different container with the same solution. From sowing spore to mature gametophytes could take as long as 12 months. In any case flood actively growing gametophytes (3-4 months old in Whittiers case) with distilled water for 4 days removing excess water. After 2-3 more months roots will appear. If the young sporephytes are given light at this stage a green leaf will appear. Then you are on your own, no attempt was made to move the plants into more natural soil. 

Growing grape ferns by Norio Sahashi

Among the Japanese grape ferns genus (Sceptridium), there are five species and three varieties in a group (Sect. Multifida) characterized by a chromosomal number of 45. Another group (Sect. Sceptridium) (n90,135; 2n=180) includes three species, one variety and four hybrids. Accordingly, a total of eight species, four varieties and four hybrids of grape fern are known in Japan. Understanding the Habitat of Grape Ferns Some grape ferns grow in bright and moist grasslands covered with grass .5-1M high. Others grow in deciduous woods which is sunless in summer but receives sun from late autumn through early spring. others can also be found in the open at the foot of a steep slope, a ski slope or a golf course, and beside an open trail leading to the top of a mountain. Some grape ferns grow in rather dark and moist woods (comprising a mixture of deciduous and evergreen trees), where it is shady and cool in summer but with sun-light filtering down through the trees after the leaves fall in autumn. There are also some grape ferns vulnerable to direst sunlight that grow in dim evergreen woods where almost no direct sunlight reaches the forest floor, or in mixed woods comprised primarily of evergreen trees. My investigations show that grape ferns prefer an illuminance of 500-3000 luxes and grow poorly outside this range. More specifically, at higher illuminance they become undersized and stop sprouting within a few years, although the roots and rhizome can survive in dormancy for several years as long as they are not extremely dry or wet. At lower illuminance, they will have no fertile blade and consequently become undersized and wither.

Planting Grape Ferns

It is difficult to raise grape ferns from spores . It is more practical to collect plants for planting in pots. young plants will develop fertile blades in a few years if they are given good care. Small plants planted in a group can be appealing, although large plants with attractive sterile blades and well-develops fertile blades can more easily yield decorative plants in a short period of time if cared for appropriately.

The rhizomes of grape ferns are upright and cylindrical and sometimes exceeds 5 cm in length, making them unfit for a shallow pot or planter. An unglazed or plastic pot will do if it is deep enough. The size of the pat should be chosen according to the length of the rhizome and a diameter about 1.5 times the mean length of the roots. A Large plant has several dozen roots (thick and string-like) which may measure 20 cm or more. When potting grape ferns, old roots and the lower part of the rhizome should be cut off preserving 10-15 cm of wrinkled roots.

When potting cover the lower 1/3 of the pot with coarse sand for drainage, and then add a mixture of leaf mold and black soil to the middle 1/3. Place a plant with roots that have been sufficiently soaked in water on the second layer. Apply flower bed soil (possessing leaf mold and good drainage) around the rhizome covering it entirely and packing the soil slightly until level. Water the plant sufficiently using a watering can, and keep the pot in the shade until the plant is established.

On of two sterile blades emerge in early summer to early autumn, usually together with fertile blades, If the first sterile blade is lost (e.g. eaten by a slug) before it opens, a second blade may develop after a while. When planting a grape fern with an open sterile blade, cut off half of the sterile blade to prevent the plant from becoming too dry. Keep the pat in the shade and watered daily until the plant is established. Grape ferns naturally grow in windless woods so it is important to avoid places that are windy or exposed to hard rains. In particular, fertile branches are easily broken and may require supportive sticks, as is the case with flowering orchid stalks.

Grape ferns can be badly damaged by snails or slugs, particularly at the time if sprouting. Even if they survive, it is possible that they will develop their fertile blades or sterile blades alone. Raising the pot off the ground using a shelf make of wire net is an effective means of preventing such damage. Chemical-based pest control is necessary at the time of sprouting.

Although the upper part of the plant, which protrudes above the ground, is resistant to diseases the underground parts (roots and rhizome) are susceptible to bacteria. When the rhizome is injured during transplanting or collecting, the plant will lose its ability to sprout within a few years. When these plants are dug up, one usually finds that the entire rhizome is rotten with only the roots left alive or that the tip of the rhizome (where three years worth of buds are formed) has been eaten by pests. In the latter case, it is possible that many young buds will emerge from the rhizome in a few years, although the probability of such an occurrence is low. It is recommended that the rhizome and roots be sterilized.

Management of Species

As mentioned earlier grape ferns are divided into two groups. The first group which has a chromosome number of 45 prefers to be grown in bright woods and grassland and is thus ill-suited to cultivation in a sunless spot. The other group, which has a chromosome number of 90 or more, prefers to be grown in dim woods, making cultivation in a place with direct sunshine inappropriate. 

Banner image (Psilotum nudum) by Tom Ranker.