Good Fronds Are Easy To Come By

As we retreat indoors for the colder months, some horticultural angst can take place.

Those who are suffering from a chlorophyll deficit could benefit from a good collection of ferns cultivated indoors. Good fronds are easy to come by.

Ferns may be the hardiest of houseplants. Look back at the great old and very cold English houses; they were adorned with ferns.

Many of the species adapt well to the low winter light. And with some weaning, many ferns will even tolerate the dry conditions that we subject our homes to in the winter months.

But ferns can be challenging as well. Keeping the humidity high enough for the wonderful staghorn fern may be tricky, but after caring for a 6-foot-tall tree fern or billowing staghorn that has been in your house for a few years, you’ll find ample payoff since a replacement of equal size and shape may be 20 to 100 times what you originally paid.

Even though most ferns used for indoor culture are native to parts hundreds if not thousands of miles south of here, they all, for the most part, prefer the combination of cool temperatures and high humidity. In the woodlands or the tropics, ferns are found under rather dense canopies of trees or large woody plants.

There are some species native to rather dry climates, which do have periods of heavy rainfall.

Years ago, we kept our homes around 75 degrees and at night we’d set the thermostat back down around 70. This would have been a bit on the warm side for most ferns but with our daytime house temperature now round only 68, tops, and night temps around 60, most ferns will be very comfortable.

The biggest challenge to growing ferns is going to be in keeping the air moist. Before the advent of forced air and steam heating there was usually one room in a house that was cooler and where the humidity was a bit higher. This was the fern room or parlor during the 18th and 19th centuries. But now it is rare to find a home with the humidity above 30 percent in the colder months.

If you decide that you can’t or won’t increase the humidity in your entire house (which, by the way, benefits you, your plants, your furniture, artwork and paint job), then you might consider a humidifier for one room. If this isn’t an option and you still want to try ferns, you can set each pot on a saucer or humidity tray filled with gravel and water. Always maintain the water level just below the top of the gravel so that the pot is never standing in water.

When the heat is on, misting the plants in the morning is also helpful. But beware that ferns with ruffles or fluffy foliage will resent being wet for long periods of time. Pay close attention to the humidity situation, as this will probably be the most limiting factor in establishing a fern collection.

As far as light is concerned, there are ferns suited to almost any condition in the average home. Holly ferns, cyrtomium falcatum, grow in low to medium light. Bird’s nest ferns, asplenium nidus, grow in low to bright light, but not in direct sunlight.

If you have young children, they will be delighted with a rabbit foot fern. This variety has ground runners that will encircle the outside of the pot, which must be clay, and as they grow and seemingly reach out, their tendrils develop a soft fur-like downy covering. Children enjoy watching the snaking growth and petting the “feet,” which can easily grow 12 to 15 inches around the pot.

My favorites are the staghorns (they do great in a bright bathroom), and the Pteris family, which includes 280 species of ferns, whose swordlike foliage can be green with silvery inlays.

When it comes to placement, a north window usually provides ideal light conditions for many types of ferns. For brighter or sunny windows, simply grow them to the side so the sun never shines directly on the plant. During the summer months, you will need to reduce light in an east or west window by at least 50 percent.

Fortunately, most ferns prefer to be pot-bound or at the very least, snug. Ideally, an attractive fern will have just enough room to accommodate the root system with about 1 inch of space for further growth. Repotting should be an annual event although larger varieties, such as tree ferns, may require repotting more often if they are growing properly and if you wish the plant to appear true to nature.

Clay pots are beyond a doubt the choice for ferns, though they can be happy and quite attractive in moss baskets. The fine fern root hairs require a good mixture of air and moisture and plastic pots, which they are frequently sold in, usually result in either too wet or too dry root zones. The experienced gardener may be able to get away with using plastic, but for all others this is a case for clay.

Growing mediums, or soils, vary considerably. But all good fern mixes have several components in common: these soils are well drained due to the incorporation of sand, grit or gravel. Considerable organic matter is of prime importance and this is found in the form of peat moss, peat humus, leaf mold or ground sphagnum moss. A typical mixture contains equal parts of peat moss, sand and unfertilized peat-based potting soil.

Remember that artificial or peat-based potting soils have very little nutritive value. Fertilizing at regular intervals is very important to keep the plants healthy, but at the same time remember that ferns are light feeders and high-dose chemical fertilizers, such as Miracle-Gro, will quickly kill them. Compost teas and fish- or kelp-based organics are perfect.

Properly watering any houseplant is not a simple three-times-a-week or every Wednesday routine. Watering ferns is no different.

I’d say that more ferns are killed from underwatering than overwatering, which is the opposite of most other houseplants. Remember that the fern’s soil is going to be rather porous—allowing rapid drainage—but at the same time the ferns tend to like it moist, but not dripping wet.

Ferns will probably require more watering in the winter since evaporation will be quicker. The simple rule to follow is never let the pot sit in water. If you have a saucer under the pot, fill it until the plant stops soaking the water up and empty the excess. If watering from above, stop as soon as the saucer or pan underneath fills, and then remove excess water.

So get yourself a new frond. And keep growing.