Boston Ferns (Nephrolepis exaltata) can be grown outdoors year-round in semi-tropical and tropical climates (USDA hardiness zones 8b-11) but what if you live in an area that freezes in winter?
Should you just let your pretty ferns die, or is it possible to overwinter them and enjoy them again next year? Indeed, it is!
In this article, we share advice and tips to help you care for your Boston Fern during the winter. Read on to learn more.
Why Not Keep Boston Ferns As Annuals?
Many people just buy new Boston Ferns in the springtime, keep them through the summer and then sacrifice them in the fall. This is certainly one way to do it, but it’s pretty wasteful.
The Boston Fern is a perennial plant. It can live for many years when properly cared for, and it will spread and multiply. This saves you money and gives you more plants to enjoy and share.
Where Should You Keep Boston Ferns In Winter?
You have two choices. You can either keep the plant as a houseplant, or you can store it in a dormant state.
Option #1: Keep your Boston Fern as a houseplant by setting it up in a location where it can enjoy an abundance of bright, indirect sunlight (minimum 2 hours) during the day. Put it near (not in) a south-facing window that gets lots of direct sunlight.
Keep the temperature in the room around 75° degrees Fahrenheit during the daytime and allow it to drop a bit at night. The temperature should never go lower than 55° degrees Fahrenheit.
Keep humidity levels high by setting your plants’ container on a pebble tray filled with water (not allowing the bottom of the container to touch the water) and misting it a couple of times a week.
If the air is very dry in your home, you may want to run a humidifier nearby. Very dry indoor air will cause leaf drops and may make your plant susceptible to problems with pests, such as scale and spider mites.
Give your plant a good pruning before bringing it in. If you are keeping it as a houseplant, prune away all older growth and just leave the youngest, newest, most recently sprouted fronds. This will help prevent older fronds from drying out and shedding messy leaves around your house.
Keep your plants’ soil slightly moist throughout the winter. You shouldn’t water it as much as you do during the growing season, but never allow the soil to dry out completely.
A thorough monthly watering should be enough but check frequently to be sure. When the top inch of soil is dry, provide water.
Use filtered water or rainwater or allow tap water to sit in the open air for at least 24 hours so that chlorine and other chemicals can dissipate.
As with most plants, don’t fertilize Boston Ferns in winter.
After all danger of frost has passed, you can begin transitioning your houseplant to the outdoors if you wish. On warm, sunny days, give it a little time in a sheltered area where it will receive bright, indirect sunlight.
Gradually increase the amount of time the plant spends outside so that it will be ready for outdoor living by the time the days and nights are consistently warm.
Option #2: Let your fern go dormant. If you don’t have a good room to keep your plant happy through the winter, you can simply store it in a dark, cool (not cold) place, such as a basement or a garage.
Cut the fronds back to a couple of inches before putting your fern in storage.
Check the soil weekly or so. It should stay very slightly moist, never soggy.
Use filtered water or rainwater or allow tap water to sit in the open air for at least 24 hours to allow chlorine and other chemicals to dissipate.
Never fertilize any dormant plant.
Early in the springtime, transition your plant to an indoor setting and begin treating it as a houseplant as described above. Once it has begun to sprout some new fronds, you can transition it to the outdoors.
Boston Fern Care Tips
Whether you keep your fern as a houseplant or place it in cool storage for the winter, there are a few things you’ll want to do to prepare it before bringing it indoors.
- No matter how you keep your fern through the winter, transition it gradually to its new setting to prevent shock.
- After pruning, give the plant a blast with the water hose to knock off any lurking pests.
- Give the plant a deep watering by soaking it in a tub of lukewarm water. This hydrates it nicely and forces pests that may be hiding in the soil to come to the surface.
- Examine the plant thoroughly and pick off slugs or other pests that may be hiding in it.
- Quarantine your plant after you bring it in. Keep it away from other houseplants for a couple of weeks to be sure it’s not bringing in pests or diseases.
- Keep all dormant plants in storage separated to prevent the spread of disease and pests.
- Check for pests and/or diseases regularly throughout the winter and take steps to mitigate them whenever you find a problem.
Why Bring Boston Fern Indoors For Winter?
In some moderately cold areas, where there is no hard freeze, Boston Ferns planted in the landscape can survive the winter if they are cut back to the ground and mulched heavily before the first frost.
In other areas, where there is no freeze at all, they might survive the winter, but they’ll take a beating and look dreadful by the time spring arrives. Additionally, in this sort of setting, they are subject to developing fungal diseases in the winter because of cold winter rain.
For these reasons, even if you live in an area where your fern could survive the winter, you may wish to bring it indoors. These pretty plants brighten up your living space and make a lovely addition to any wintertime plant room.