Hartley Magazine

All the latest news, hints, tips and advice from our experts

Fresh and fine

The fine, feathery leaflets of ferns dry out easily without high humidity. If you don’t have a waterfall, you’ll need to make an extra effort.

I love the light, airy feel of ferns. Unfortunately, this is one category of houseplants that have a very tough time making it through the heating season in the dry air of a living room. A conservatory? That’s much more likely to be good fern habitat.

One of my favorite places is the Fern Room of the Garfield Park Conservatory in Chicago. It was designed in 1908 to resemble the landscape of the Midwest in the Jurassic period 200 million years ago, when the dinosaurs roamed. It’s warm and moist and full of ferns—and plenty of fern fossils have indeed been found from the Jurassic. They may not be exactly the same species that we find today as garden plants or houseplants, but still, it’s a reminder that these ancient plants are survivors.

There are plenty of temperate-zone ferns—I have several species in my garden—but the ones we grow indoors come, like most of our houseplants, from rainy tropical forests.

Even more than most houseplants, ferns need high humidity. That’s because they have a lot more edges than most plants, and edges are where leaves dry out. If you look at the long leaf, or frond, of a fern, you’ll see that it’s deeply notched into dozens of leaflets. That’s what gives these plants their lovely air of lightness. It’s also what makes them so vulnerable to dry air.  The same is true of many plants with delicate, slender leaves, including the plant we call asparagus fern (Asparagus aethiopicus), although technically it isn’t a “true” fern.

Think of your bathroom after a long, hot shower, and you’ll know what your fern needs. In fact, a very bright bathroom is a good place for a fern. Otherwise, you’ll need to make an effort to raise the humidity level in the air enough to keep most ferns fresh and green.

Spritzing the plants from a spray bottle won’t help much. Instead, encourage water to evaporate into the air. Leaving some buckets of water around a conservatory will help, but it helps more to bring the vapor closer to the plant.

One way is to place a few river rocks in a large saucer, fill it with water, and set the fern’s pot on the rocks. Water will evaporate from the saucer up around the fronds. Make sure the pot always sits above the water level, so surplus water can drain away from the soil and the roots don’t rot. Refill the saucer as needed. Or fill an entire large tray with water and set several plants up on rocks. They’ll all share the water vapor and, as a group, help keep each other moist.