The Boston fern (Nephrolepis exaltata) is a popular houseplant for rooms that receive bright, indirect sunlight.
You can grow this pretty plant outdoors year-round if you have a shady, sheltered yard in a tropical area (USDA hardiness zones 9-11). They do well as understory plants for trees and bushes, as bedding plants in shady areas, or naturalized in a woodland setting.
This article discusses outdoor care for Boston ferns and shares advice to help you grow these attractive plants.
Choose And Prepare The Right Setting
Outdoors, Boston fern plants do best in a sheltered setting with moist soil, consistent warmth, humidity, and partial or dappled sunlight.
If you live in an area that experiences some light frost, your plants may die back in the wintertime. As long as the roots don’t freeze, the plants should grow back nicely in the spring.
Sun
Sunlight is your first consideration. You will want to shelter your plants from harsh sunlight and high winds.
A setting near a wall or in a grove of trees that provides some morning sun, along with shelter from noonday and afternoon sun, is good. Dappled sunlight or high shade all day long will work as well.
Wind
Provide a windbreak. High winds can batter these plants and make them look dreadful.
Harsh wind also brings sudden temperature changes, which can kill your plants. For this reason, be sure to plant them in an area protected from the wind by a wall or stand of trees or bushes.
Planting in a small walled garden, the corner of a fenced yard, or any L-shaped bend where two walls meet can be a good idea.
Water
Be sure you have a water source nearby. These plants need consistently moist soil (never soggy).
Generally speaking, a weekly soaking supplemented by daily watering makes a good watering schedule. During scorching weather or times of drought, you may need to water a couple of times a day.
Unlike watering instructions for many plants, overhead watering is ideal for Boston ferns. Situate them in an area where you can shower them with a spray nozzle on your garden hose.
Soil
These jungle plants like very light, loamy, rich, well-draining soil. Before planting your Boston ferns, till the soil and work in some compost, leaf mulch, or finely chopped bark.
After planting, mulch around the plants to help the ground keep water. As the mulch decomposes, it will feed the plants. You can turn it into the soil and add a fresh layer every spring.
Fertilizer
Boston ferns are not heavy feeders. If you have well-amended soil and add fresh mulch every spring, you may not need to fertilize.
If your plant’s leaves are sickly looking (pale green or yellowish), you may wish to provide a light feeding of good water-soluble fertilizer. Fertilize no more than once a month during the spring and summer.
Another way to fertilize is to feed slow-release fertilizer early in the springtime and mid-summer.
Pest Control
Outdoors, Boston ferns are subject to slug infestation. The best ways to deal with slugs are also the most natural ways. They may have the added advantage of amending the soil and feeding your plants.
First, when you see slugs, remove them by hand. Be sure to wear disposable gloves to protect yourself against germs and disgusting slime.
Carry a bucket of soapy water with you when you go slug hunting and drop them (and other significant pests) in when you find them.
Second, cover the soil around your plants with sharp substances such as diatomaceous earth, eggshells, and coffee grounds.
Slugs do not like to glide across these painful substances, and these all break down nicely and nourish the soil.
There are commercial slug poisons available, but they are no more effective than natural solutions. Also, they pose some threat to kids, wildlife, and birds.
Don’t use salt. It will kill slugs, but it will also poison your soil and kill your plants.
Pruning
Throughout the growing season, prune away dead or damaged fronds as needed. Late in the autumn, you may wish to cut your ferns back to ground level to help protect them from the cold winter months.
You can add a layer of mulch to give the roots a little insulation. Your Boston ferns will return with bright, all-new foliage when the weather warms up.
Can Boston Ferns Be Grown In The Landscape In Cold Climates?
You can grow these perennial plants as annuals in colder climates by following the advice above. When cold weather comes, you can dig them up and bring them indoors to overwinter or accept that they will soon perish.
In climates that don’t experience a hard freeze, try cutting the plants back to the ground and mulching heavily before the first freeze. They may surprise you by returning in the spring.
What About Container Plants?
If you live in a cold area, it’s a good idea to let your Boston fern enjoy the warmer months outdoors. To do this, transition your houseplants gradually to an outdoor setting with shelter, warmth, humidity, and light, as described above.
Good locations for container Boston ferns include covered decks, patios, and porches. They do well in hanging baskets in these settings.
You might set your fern under a shady tree or near a backyard pond, as long as the light is right and there’s not too much wind.
Before the weather turns cold, you’ll want to bring your potted Boston fern back inside. Keep your plant in a room that receives bright, indirect sunlight and stays comfortably warm.
To keep your indoors tidy when you bring your fern in for the winter, you may wish to cut it back to about 2″ inches high to prevent leaf drop. This act may also spur it to generate new growth.
If it looks too pretty to cut back, leave it. If it starts looking shabby and making a mess during the winter, you can give it a good pruning.