Healthy Ferns: Time for Summer Look at Ferns

When ferns gradually look poorer, it is time to check them over and start remedial treatment promptly. Three possible steps to improve sick ferns include: 1. moving them outdoors. 2. re-potting or 3. evaluating and possibly changing conditions the plants have experienced indoors. Plants moved outdoors are exposed to higher humidity and dew. Light is better than indoors, and free air movement means better oxygen-carbon dioxide exchange on the leaves. All these may lead to better growth. However, plants must be moved outdoors with caution. They cannot be put in direct sun. Therefore, a sheltered location must be selected carefully.

Any plant in a pot will dry quite rapidly outdoors. Daily waterings are normally required when there is no rain. If conditions are very dry, even more frequent watering may be necessary. Extra watering means extra fertilization, but no stronger fertilization. As a plant adjusts to the outdoors, and fall nights become cooler, the fern given good care should develop vigorous new growth that will make the extra work worthwhile. The added vigor the plant develops makes it better able to endure less favorable conditions indoors. Plants that have outgrown their pots are usually divided and reported as new growth begins in spring. However, re-potting and division may still be done this summer, if necessary.

A root-bound mass of a well established fern forms a tight ball. Although it may seem harsh, a sharp, long knife should be used to cut the plant root mass in half or quarters. Additional divisions can then be pulled from these if desired. However, the more divisions are made, the longer it will take the new plants to recover and begin growth. Ferns are not well adapted to heavy clay soils. Potting soil should be light and fibrous with liberal amounts of organic matter. It must also be well drained. A typical mix might contain equal parts of peat moss, sand and rich soil. One teaspoon of ground limestone per quart of mix is also helpful to most ferns.

The "sand" portion of the mix is better for many ferns when composed of one part coarse sand, one part small gravel, and one part charcoal. When indoors, ferns do not like either direct sunlight or very poor light. Most of them like a diffuse, but strong light. If only a sunny window is available, a sheer curtain between the window and the plants provides adequate protection from the direct rays of the sun. Sun in midwinter is not harmful. If no bright location is available, fluorescent lights may be placed over the plants.

Ferns like high humidity and cool temperatures. Misting over the plants or increasing humidity with a vaporizer, humidifier, or trays of water is helpful. Best temperatures are 55 to 60 degrees at night and 70 degrees during the day. Never fertilize heavily. Apply a soluble house plant fertilizer at half normal strength about monthly. Always keep ferns moist, but not standing in water or watered so frequently that the soil remains soggy. Even at their best, ferns will occasionally die. Remove any dead leaves promptly so the plant is always at its best appearance.

http://en.wikipedia.org/wiki/Fern