How To Care For A Maidenhair Fern In Winter

Understanding how to care for a maidenhair fern in the winter is a new problem for me. I’ve owned no less than three of them over the years, but the first two both met crispy deaths in the same summer I bought them. And yet, I can’t help finding their frothy, delicate foliage completely irresistible. And so far my third maidenhair fern has hung on in my home for six high-maintenance months. But as winter starts to draw in, I’ve noticed some changes in its appearance. Which sent me on a research mission to find out exactly how my maidenhair fern is going to behave over winter. And what I need to do to keep it healthy until spring. Here’s everything I’ve learned!

• Maidenhair ferns 101
• How to care for a maidenhair fern in the winter
• Temperature
• Humidity
• Light levels
• Feeding

Maidenhair ferns 101

Maidenhair ferns (Adiantum raddianum) are also known as Venus hair ferns, and delta hair ferns. They’re native to the tropical rainforests of South America and the West Indies, where they poke out of rocky crevices alongside rivers and waterfalls. In fact they’re so highly adapted to this warm, wet environment that they’re notoriously tricky to keep happy as houseplants. They tend to do best out of direct sunlight, in spots with high humidity, like bathrooms or terrariums.

My maidenhair fern lives in our snug. Since I bought it in spring, it’s been getting a moderate amount of indirect light every day, and I’ve been diligent about watering and misting it every two or three days. But as I write this in late November, I’m confronted with unmistakable signs that my maidenhair fern is not completely happy. For reference I live in a temperate maritime region, somewhere on the cusp of climate zones 8 and 9. So the days are getting much shorter at the moment, the weather is hopelessly gray and wet, and the outside temperatures are tracking ever downwards.

I’ve been researching how the changing seasons are taking my maidenhair fern out of her comfort zone, and what I need to do to stop her going the same way as her predecessors, and ending up on the compost heap!

How to care for a maidenhair fern in the winter

Maidenhair ferns are adapted to thrive in a sheltered spot in a fairly unchanging, warm and humid climate. They are not very resilient or adaptable to changes in light, temperature or humidity, because they have never needed to be. Depending on your region, and where you keep your maidenhair, there might be a period during the year when they’re in their element without a lot of input from you. But if like me, you have cold winters, it’s likely you’ll need to change the way you think about them in winter.

Temperature

Maidenhair ferns like warm temperatures. They’re happiest between 65 and 75°F, but they tolerate rooms down to about 60°F. If their spot dips below 50 or 55°F, your fern is likely to start turning brown and losing leaves. They equally dislike their environment getting too hot, as it tends to drive away humidity. Which causes their thin, delicate leaves to dry out.

Maidenhairs don’t just dislike extremes of hot or cold – they absolutely loathe lurching from one to the other. And this can be a problem if they’re positioned in a spot near a hot air vent, radiator, wood stove or fireplace in winter. My maidenhair sits two feet from a radiator which was off all summer, but now comes on on a timer twice a day. The snug is less well insulated than the rest of our house too, so it gets pretty cold when the radiator is off. In other words, my poor maidenhair is suddenly being exposed to a rollercoaster of temperature changes every day! So one thing I’ll be doing is moving my fern into a room we manage to keep more evenly heated in the winter months.

Humidity

Maidenhair ferns love relative humidity of 60 – 80%. However, keeping our homes that humid is a recipe for problems with damp and mold, and all the health risks and potential for damage that come with them. In fact, it’s much better for us to keep our rooms between 40 and 60% relative humidity. This means that in order to keep everyone happy, maidenhair ferns need their own little humid microclimate. This could mean:

• Keeping them in a room with high humidity, like a bathroom.
• Growing them in a terrarium.
• Misting them every day or two.
• Or standing them on a tray of pebbles half-filled with water.

Whatever approach you take, you’ll need to make sure you adjust for the effect of turning on your heating in winter. Wherever I move my fern to, I’ll be misting every day from now on until we stop using the radiators again in spring. And since our 1930s house really does get damp between fall and spring, I’ll also be making sure that whenever my husband runs the dehumidifier to protect everything else, my fern is safely out of its way!

Light levels

Maidenhair ferns are forest floor plants. In their native environment, the light which reaches them has been filtered through tens or even hundreds of feet of foliage from other plants. So they’re adapted to relatively gloomy conditions. But seasonal changes in daylight hours are also relatively small near the equator. The shortest day is only 3 or 4 hours shorter than the longest. On the other hand, where I live our shortest day is more than 7 hours shorter than our longest. Until now, I’ve exploited my fern’s tolerance for low light and used it to cheer up a relatively dark corner. But maidenhairs are adapted to low light, not no light! So now I’ll move it somewhere that gets a bit more sunshine (when the weather’s playing ball!)

Feeding

There’s one more thing to change in winter. During spring and summer, maidenhair ferns flourish with the addition of a little liquid plant food once a month, diluted to half the strength recommended on the packaging. But come fall, that’s going to change. Maidenhairs grow much more slowly in fall and winter, meaning they have no use for fertilizer. So leave the cap on the bottle for now.

How to care for a maidenhair fern in the winter – summary

Following my research, I’m confident I can keep my maidenhair fern alive and happy throughout the colder months. In summary:

• Protect them from winter chills below 60°F
• Move them away from hot air vents, radiators, stoves and fires which drive the humidity away and cause them to dry out.
• Move ferns in very dark corners closer to a window, to make the most of the daylight available on shorter days.
• Stop feeding them until spring.

And remember:

• It’s normal for maidenhair ferns to lose old leaves every now and then. They will be replaced with new ones, but this process is slower over winter, and speeds up again in spring.
• Maidenhair ferns grow from a crown – an area of connective tissue level with the top of the soil, which joins the leaves and roots. Whilst its leaves hate dry conditions, it’s crown will simply go dormant until water is available again. So if the central heating kills off the foliage on your fern, water the soil, pop a sandwich bag over the pot to trap humidity, and wait!

Let us know if your maidenhair fern has been showing signs of distress this winter in the comments bow down below. Good luck restoring them to good health!