Boston Fern: Plant Care and Grow Guide

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The Boston Fern has become one of the most popular houseplants today for its lively, lush, green, happy appearance. These plants are still being grown today because of their beauty and versatility.

They can be found at any garden center or home improvement store. This houseplant requires little care but do need some light during the day.

Let’s get into the details of how to care for and grow the Boston Fern plant. 

Boston Fern Overview

A member of the Dryopteridaceae family, the Boston Fern’s botanical name is the Nephrolepsis exaltata bostoniensis. 

The Boston fern mutation was discovered in 1895 in the midst of two hundred sword ferns by a florist near Boston. The Sword Fern species is native to Florida and the American tropics.

There are more than 200 varieties of the Boston Fern.  Some popular cultivars include:

  • Nephrolepsis exaltata “Compacta” – A short very compact fern.
  • Nephrolepsis exaltata “Florida Ruffle” – A medium sized-fern with ruffled, feather-like fronds.
  • Nephrolepsis exaltata ”Fluffy Duffy” – A very dense small fern with feathery fronds that boast a fine texture.
  • Nephrolepsis exaltata “Golden Boston” – A fern with fronds that are yellow-green.
  • Nephrolepsis exaltata “Rita’s Gold” – A compact fern with chartreuse-tinted fronds.

Boston Fern Care

Boston ferns appreciate an extra bit of care. They like their environment to be humid and warm. They suffer when exposed to extreme temperatures when cultivated outside.

Indoor fens need to be protected from drafts and should not be positioned near heating or air conditioning vents. These plants do best when in a stable environment.

Frequent watering is a must to keep the soil bed from drying out. They should be fed the entire growing season from spring to autumn. Humidity is also a necessity for your plant’s overall health.

Soil for Boston Fern

The Boston fern prefers a soil bed that is a rich loamy peat-based potting mix with excellent drainage.

If the soil bed does not drain adequately, root rot may ensue and kill your fern. You can mix a potting soil that is 50% peat moss, 12% horticultural bark, and 38% perlite.

Light for Boston Fern

Boston ferns like very bright, but indirect light. If they are in a very shaded area, their fronds may suffer in appearance. 

Too much direct sunlight will burn their fronds. Whether you cultivate your fern indoors or outdoors, they should have access to bright light, but no direct exposure to the sun.

Too much sun will scorch the foliage, too little sun will cause the plant to drop its leaves.

Water and Humidity for Boston Fern

It is important that the soil bed of your Boston fern is always kept moist. It should not be soggy or water-logged, but always moist. If the soil bed dries out, the foliage will follow suit, drying out and dropping from the plant.

In the autumn and winter, watering can be reduced somewhat, because the plant is not growing. However, always keep an eye on the fronds. If they look dry, you need to water more often or increase the amount of water given.

A dry soil bed is the number one reason that Boston ferns fail. A good option is to soak your Boston fern monthly, particularly for the peat moss in the potting mix. Leave the plant to drain thoroughly before placing it in its usual location.

Also, it is recommended that you use rainwater or water that is not chlorinated when watering your Boston fern. Tap water can often contain fluoride and chlorine, but that doesn’t mean you can’t use it either.

Leave tap water out overnight in a container and that will allow the fluoride and chlorine to dissipate before you water the plants. Leaving water out can also help with adding moisture in the air for the Boston fern.

High humidity is a must for Boston ferns. They do best in environments that have 80% humidity or above. This is a wonderful plant for bathrooms.

If you do not have particularly high humidity in the space where your fern is located, use a space humidifier, or a tray filled with pebbles and water. The plant should sit on the tray but above the waterline. The container should not come into contact with the water.

You can also fill a receptacle with water and place it near the plant to help. Misting the leaves can also help.

Should your fern be suffering because of low humidity levels, the tips of its fronds will become brown. If you do not increase the humidity, this will spread from the tips to the entire plant. Fronds may also turn yellow when humidity is too low.

If your home has heating in the winter, watch the humidity levels. You can let them go dormant and place them in a garage, basement, or similar as long as temperatures do not dip below 35°F.

While the Boston fern is dormant, it is not necessary to provide light as the plant is sleeping. It should still be watered thoroughly, at least once a month.

If you are moving the plant, acclimate it gradually to its new location. Avoid an abrupt switch.

Temperature for Boston Fern

A constant mild temperature between 65° and 75° Fahrenheit is ideal for the Boston fern. They do not tolerate extreme temperatures whether hot or cold.

Temperatures that rise to 95°F or above will harm your fern, as will temperatures that fall to 35°F and below.

Boston ferns can be left outdoors in the winter if you reside in an area that is subtropical, meaning without freezing temperatures or frost.

Fertilization for Boston Fern

The Boston fern should be fed from spring to the beginning of autumn using a liquid fertilizer diluted to half strength on a monthly basis.

Foliage should be rinsed after fertilization to prevent burning the leaves. During the dormancy period from the middle of fall through the winter, they do not require fertilizing.

The use of an Epsom salt solution of two tablespoons per gallon of water, applied twice annually, will contribute to maintaining its vivid green color.

Boston Fern Pruning and Repotting

For pruning, look to the Boston fern’s leaves. Old fronds that may be yellow or brown should be snipped at the soil bed level to encourage new growth. If you have runners dangling without leaves, your fern needs a trim.

If you wish to do radical pruning, it should be done in the spring or summer. This plant responds well to radical pruning.

Use clean scissors or a pair of pruning shears. Avoid cropping the plant’s top, but work at the base from the sides. You can then clip the plant to your desired shape. If necessary, you can cut the plant to the base.

Boston ferns should be cultivated in containers that are approximately one inch larger than their root ball, and the pot should have very good drainage holes.

If you notice roots that are peeking out of the soil bed, you will know that you need to repot, because the Boston fern is growing too big for the container. Another hint that it’s time to repot will be if the plant slows its growth.

It is best to repot your Boston fern in the springtime. Remove it from the container gently and remove some of the old soil. Place it in its new pot with fresh soil mix.

Propagating a Boston Fern

The Boston fern is easiest to propagate by crown division. When you repot in the spring, you can separate and cut a section of your mother plant, making sure that some roots remain attached.

You can do this by cutting both larger or smaller sections. Place your divided section in its own container with a fresh soil bed, and water. Keep the soil bed moist at all times, same as you would for a mature Boston fern.

Also keep your baby fern in a warm spot far from drafts, breezes, direct sunlight, and changes in temperature.

When you notice some resistance while pulling gently at the base of the fern, you will know that the roots have established themselves.

Boston Fern Toxicity and Pets

According to the American Society for the Prevention of Cruelty to Animals (ASPCA), the Boston Fern is non-toxic for both cats and dogs.

Boston Fern Pests, Diseases, Problems, and More

While not particularly at risk for disease and pest infestations, Boston ferns are still susceptible to a few diseases and insects, in particular mealybugs and spider mites.

You can treat your fern to a good shower to help remove some pests and then apply an organic insecticidal soap or neem oil. It is important to treat the infestation immediately.

If foliage turns dark brown or black, it may be a sign that the soil bed has nematodes. In that case, add compost to the soil to encourage the development of fungi that are beneficial.

If the infestation is advanced, you should eliminate infected plants. Brown and black spots with a bad odor indicate bacterial soft rot and the plant should also be eliminated.

Leaf tip burn will manifest with brown withering frond tips. Rhizoctonia Blight manifests itself with brown or black spots near the plant’s crown that spread rapidly. In this instance, the fern needs to be sprayed with fungicide.

Outdoor Cultivation of the Boston Fern

Although usually grown as a houseplant, a Boston Fern can do exceptionally well outdoors if the climate is warm and humid. They can survive in dryer climates if sufficient water is provided.

The fern should be positioned in a location that offers partial to full shade. It will require water because it is not drought-tolerant. Mist your fern on very hot days.

When cultivated outside, your fern will be susceptible to visits from slugs. If there are only a few, you can remove them by hand.

Placing a coarse substance around the Boston fern will also dissuade slugs, such as coffee grounds, broken dry eggshells, or diatomaceous earth. You can use slug pellets but follow the product directions carefully.

Growing Boston Fern Final Thoughts

The Boston Fern is an old-fashioned, elegant parlor plant from days gone by. It is a perfect decorating choice for any room or location and will add lush greenery to your home or office decor.

For more guides on growing houseplants, here are some more articles: 

Growing Boston Fern FAQs

How much sun does a Boston Fern need?

The Boston Fern likes bright indirect light. Direct sunlight can scorch the leaves, so be sure it gets some shade and filtered sunlight. 

What kind of soil mixture works best for my Boston Fern?

Use a potting mix rich in peat moss and perlite for the Boston Fern. This combination provides excellent water drainage and air circulation.

Is it okay to fertilize my Boston Fern?

Yes! Fertilizing the Boston Fern helps promote healthy growth and blooms. Use a balanced liquid fertilizer every month during the spring, summer, and early fall months. 

Are Boston Ferns hard to care for?

Boston Ferns are easy to grow once they have been established. The key is providing adequate water, light, and nutrients throughout the growing season.

Can a Boston Fern live outside?

Yes, a Boston Fern can live outside as long as the climate is warm and humid. Be sure to monitor the soil regularly for moisture. Water the plants when the soil is dry. Be sure that there’s also shade, so there aren’t long exposures to direct sunlight that can scorch the leaves.

How often do you water a Boston Fern?

Watering depends on how frequently you notice signs of dehydration. A good rule of thumb is to water at least once a week. Keep the container slightly moist at all times. The length of time the soil stays moist will depend on your local environment, so keep an eye on it for how often to water.

Do Boston Ferns have to hang?

No, although many people prefer hanging their Boston Ferns. Hanging allows more natural movement than planting directly into pots on the ground. 

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Written by:

Amy Walsh
Amy Walsh is a passionate indoor gardener, deeply engrossed in the world of houseplants and herbs. Her apartment is a lush sanctuary of foliage, reflecting her journey from hobbyist to devoted botanist. She's constantly exploring the latest in smart garden technology, eager to share her insights on nurturing green spaces indoors. Alongside her botanical pursuits, Amy enjoys connecting with nature and friends, continually enriching her lifestyle with greenery and growth.

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