Thankfully, ferns are easy plants to care for. They don’t need repotting all that often, probably every four or five years, but in late January every year it’s customary to check plants to see what needs to be done. Turn the pot or container on its side and check the drainage holes for signs of roots crowding the holes or starting to grow out. Ferns usually provide signals when they are pot-bound: roots about to exit the drainage holes. If you find roots there, repot the fern in the next week or two. If no roots cover the drainage holes inside the pot, you need only improve the soil at the top of the pot.

Here are a few management summaries for indoor ferns:

* Bird’s Nest Fern: soil should be equal parts of milled sphagnum peat moss, perlite and vermiculite (the so-called Cornell Mix) . . . keep the soil lightly moist at all times, with humidity between 30-45 percent . . . northern exposure or subdued light is needed . . . don’t overwater and avoid cool drafts indoors.

* Boston Fern: the Cornell Mix is the best soil . . . plant does best with eastern exposure and filtered sunlight behind a curtain . . . soil should go moderately dry between waterings, 40 percent humidity . . . foliage frequently browns over the winter, so prune fronds away.

* Button Fern: use the Cornell Mix . . . let soil go fully dry between waterings, 40 percent humidity . . . best grown in poor light, eastern or western subdued exposure . . . soil must drain well at all times.

* Holly Fern: use the Cornell Mix . . . soil should dry lightly between waterings, 40 percent humidity . . . takes bright indirect sunlight in any room . . . easiest indoor fern to grow, tolerates neglect for novice gardeners.

* Maidenhair Fern: use the Cornell Mix with humus or some compost added . . . soil must be kept moist at all times, but avoid overwatering . . . 40 percent humidity is a priority . . . best grown with subdued light with northern exposure.

* Rabbit’s Foot Fern: use the Cornell Mix with humus or compost added . . . soil should dry lightly between waterings, 30 percent humidity is fine . . . provide eastern or northern exposure with low light . . . easiest indoor plant of all ferns.

* Shield Fern: use the Cornell Mix with some humus or compost added . . . soil must be lightly moist at all times, but avoid getting water on the foliage . . . needs a strong humid environment, 40-50 percent . . . eastern exposure is best year-round.

* Staghorn Fern: use the Cornell Mix with humus or compost added, and a handful of osmunda fiber . . . soil should dry between waterings . . . normal humidity is OK . . . best grown behind a thin curtain with western exposure.

If repotting is needed, remember to let the soil go fairly dry. At this point, the rootball should start shrinking away from the wall of the pot. Strike the base of the pot with your fist and the plant should come out, rootball and all, intact. Add an inch or two of warm water to a plastic dishpan, and then dip the bottom of the rootball in water to moisten the soil. On newspapers set on the kitchen counter, turn the rootball sideways, then use a kitchen fork to dislodge the moist soil on the bottom half of the rootball. Careful forking away of the old soil will save the roots.

Increase plastic pot diameter to two inches wider than the old. Line the base of the new pot with broken-up Styrofoam pellets or exploded popcorn.

Using a paper bag, add equal amounts of milled sphagnum peat moss, perlite and vermiculite (the Cornell Mix), secure the bag at the top with your hands, then shake for 15 seconds to homogenize the soil. Add a pinch or two of bone meal to your mix. Put your mixed materials in a plastic dishpan, followed by hot water; stir your materials with a plastic spatula, then spoon the wet soil onto sheets of newspaper on the kitchen counter to dry for 5-10 minutes. Spoon the soil so it fills the new pot about halfway.

Now, check the fern. Set the rootball into the pot to see if more soil needs to be added to position the plant in the top half-inch of the pot. In most cases, soil will have to be added to the pot.

Take time now as you repot. Set the plant atop the soil in the pot, spooning your pre-wet soil around all sides of the rootball so soil contacts all roots. By now, the pot should be resting in the kitchen sink. Add tepid water to move the spooned-in soil to the base of the rootball. Don’t worry about having to spoon in ample amounts of soil, followed by more water. All roots at the base of the rootball must come in contact and be surrounded by then soil you are spooning in. When the fern is secured in the pot, a final watering will remove any air pockets.

As for providing humidity, ferns must be double-potted at all times to avoid browning of the tips of fronds, also to avoid defoliation by mealybugs and spider mites.

If repotting isn’t needed this winter, pre-mix a small amount of your moist Cornell Mix in a plastic dishpan. Moisten the fern with warm water under the kitchen faucet, wait a few minutes, then carefully spoon off the top inch of old soil. Replace it with your moist Cornell Mix, followed by another soaking of tepid water to cement the new soil to the old.

All indoor ferns need a soil pH between 6 and 7. After caring for your ferns, run a soil pH test with your electronic pH soil tester. Soil must contain some moisture for valid test results. If the pH is near 6 or below, sprinkle a teaspoon or two of pulverized lime atop the soil before the next watering. One pinch of 20-Mule-Team Borax to a half-gallon of water twice a year works wonders; apply only enough of this solution to wet the soil of each fern twice a year.