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The Boston fern (Nephrolepis exaltata Bostoniensis), often referred to as a sword fern derivative of all cultivars of N. exaltata, is a houseplant popularized during the Victorian era. It remains one of the quintessential symbols of this time period. The commercial production of the Boston fern began in 1914 and includes around 30 tropical species of Nephrolepis cultivated as potted or landscape ferns. Of all fern specimens, the Boston fern is one of the most recognizable.
Propagating Boston ferns isnt too difficult. Boston fern propagation may be accomplished via Boston fern shoots (also referred to as Boston fern runners), or by dividing Boston fern plants. Boston fern runners, or stolons, may be removed from a mature parent plant by taking the offset whose runners have formed roots where they come into contact with the soil. Thus, the Boston fern shoots create a new separate plant. Historically, the early nurseries of central Florida grew stock Boston fern plants in beds of cypress-covered shade houses for the eventual harvest of the Boston fern runners from older plants to propagate new ferns. Once harvested, these Boston fern shoots were wrapped in newspaper bare rooted or potted, and shipped out to the northern reaches of the market. In this modern era, stock plants are still kept in climate and environmentally controlled nurseries wherein the Boston fern runners are taken (or more recently, tissue-cultured) for propagating of Boston fern plants.
As a long-time gardener, I’ve learned that dividing perennials is one of the best ways to get more plants for free. This is especially true for ferns like the Boston fern, which can easily be divided into multiple new plants.
The Boston fern (Nephrolepis exaltata) is one of the most popular ferns grown as a houseplant. It has gracefully arching fronds that can grow quite large often getting up to 5 feet long! While having a huge Boston fern may look impressive it can be difficult to manage its size indoors. The good news is that Boston ferns are one of the easiest ferns you can divide.
Why Divide a Boston Fern
There are a few key reasons you may want to divide your Boston fern:
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Control the size – Large Boston ferns can be hard to manage indoors. Dividing it into smaller plants helps control its spread.
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Propagate new plants – Dividing ferns is an easy, free way to get more plants. Boston fern divisions can be potted up for your home, given as gifts, or traded with fellow gardeners.
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Rejuvenate overgrown plants – Old, overgrown Boston ferns often have unattractive, congested root balls and misshapen fronds. Dividing them gives you fresh, new starts with full, beautiful fronds.
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Renew tired plants – Dividing stimulates new growth and can rejuvenate old, tired plants. The divisions act like young seedlings.
How to Divide a Boston Fern
Dividing a Boston fern is a simple process. Follow these steps:
1. Remove from Pot and Prepare Root Ball
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Carefully remove the fern from its pot. Knock off any old soil clinging to the roots.
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Use a knife to slice through the root ball in half. Then slice each half into quarters.
2. Make Divisions
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Cut a 2-3 inch section off each quarter root section. This will be your new division.
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Trim any long roots and retain just 1-2 inches of root on each division. This helps stimulate new root growth.
3. Pot Up Divisions
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Prepare small 4-5 inch pots with drainage holes, and a well-draining soil mix.
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Place each fern division in a pot, spreading its roots out. Fill in around roots with soil.
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Water well and place in a bright, shaded spot while the new plants establish.
4. Ongoing Boston Fern Care
To keep your divided Boston ferns looking their best:
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Water frequently, allowing the soil to dry out slightly between waterings.
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Provide high humidity by sitting pots on pebble trays or grouping plants together.
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Give bright, indirect light indoors near an east or west window. Protect from direct hot sun outdoors.
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Feed monthly during spring through fall with a balanced liquid fertilizer.
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Prune off any dead or damaged fronds to keep plants looking tidy.
Tips for Dividing Boston Ferns
Follow these tips to ensure success dividing your Boston ferns:
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Divide ferns in early spring or fall. Avoid the heat of summer.
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Discard any diseased or pest-infested sections of the plant. Only divide healthy ferns.
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Use sterile pruning shears and knives to prevent disease spread. Wipe tools with isopropyl alcohol between cuts.
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Allow divisions to dry out slightly before potting up. Freshly cut roots are prone to rot if kept too wet initially.
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Pot into a loose, well-draining soil mix. Avoid heavy potting mixes that retain moisture.
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After dividing, don’t overwater newly potted divisions. Wait until soil is partly dry before watering again.
Troubleshooting Problems After Dividing Boston Ferns
Sometimes Boston fern divisions can struggle after being separated from the parent plant. Here are some common problems and solutions:
Yellowing fronds – This is usually caused by dry soil. Increase watering frequency and provide higher humidity.
Brown leaf tips – The most common cause is dry air. Increase humidity through grouping, pebble trays, and misting.
Root rot – Overwatering is the culprit. Allow soil to partly dry out between waterings.
Few new fronds – Low light causes limited new growth. Move plant to a brighter location.
Leggy growth – Insufficient light leads to spindly fronds. Provide bright, indirect light to encourage full, compact growth.
Dividing Ferns Opens Up New Possibilities
Learning how to divide a Boston fern gives you an easy way to generate new plants from a single purchased fern. You’ll find dividing ferns is highly rewarding. It allows you to create lush containers of Boston ferns to brighten up your indoor space or outdoor garden. Plus you can share the joy with others by gifting Boston fern divisions.
Propagating Boston Ferns via Boston Fern Runners
When propagating Boston fern plants, simply remove the Boston fern runner from the base of the plant, either with a gentle tug or cut with a sharp knife. It isnt necessary that the offset have roots as it will easily develop roots where it comes into contact with soil. The offset may be planted immediately if removed by hand; however, if the offset was cut from the parent plant, set it aside for a couple of days to allow the cut to dry and heal over. Boston fern shoots should be planted in sterile potting soil in a container with a drainage hole. Plant the shoot just deep enough to remain upright and water lightly. Cover the propagating Boston ferns with a clear plastic bag and place in bright indirect light in an environment of 60 to 70 degrees F. (16-21 C.). When the offshoot begins to show new growth, remove the bag and continue to keep damp but not wet.
How to Divide a Boston Fern
FAQ
When should I split my Boston fern?
Wait until it gets big enough to merit dividing, because otherwise it’s just unnecessary stress. My own personal benchmark for when a Boston fern needs dividing is when the overall foliage mass is about the size and shape of a laundry basket, which means the crown is about two fists in diameter.
What time of year do you split ferns?
Dividing ferns with several crowns
Other ferns may look as if they have several crowns, but are in fact a clump of different plants, potted up together by the nursery. In both cases, you can split the crowns apart in spring, using two back-to-back forks, and pot up or replant them individually.
Can I cut a Boston fern in half?
Unpot it and cut it in half. The roots are so dense its impossible to separate them. They fill in pretty pretty quickly. Lots of water in indirect sunlight.May 1, 2025
When should a Boston fern be repotted?
Repot a Boston fern once every 2 years in a pot that is 2” larger than the current one.Feb 21, 2024