Boston fern care and growing guide: expert tips to master

Also known as the sword fern, the Boston fern is an elegant houseplant, that will create a lush look in your home, with its fountain of bright green frilly foliage. 

The arching leaves, known as fronds, can grow up to 3ft (90cm) in length, given the right conditions, and make a beautiful feature when cascading from a hanging basket or displayed in a pot on a tall stand. 

Boston ferns (Nephrolepis exaltata) hail from the forests of South and Central America, and consequently prefer a warm humid atmosphere that replicates their native habitat. However, while this fern comes from swampy areas, it is an epiphyte, which means it lives among the branches of trees, so it will not be happy in sitting in soggy soil.

You may find the Boston fern listed under Nephrolepis exaltata ‘Bostoniensis’ which is a popular plain green variety. Or try the variegated form N. exaltata ‘Tiger Fern’, with its unusual yellow-streaked foliage, which is also one of the best indoor plants. 

3 essential Boston fern care tips to follow

Tom Knight of Our House Plants says the Boston fern is a good choice for beginners wanting to start their own indoor garden: 'It’s readily available, relatively cheap and offers a great way to enjoy lush green foliage, in the feelings of tranquility it seems to evoke.'

1. Find the right light for your Boston fern

Tom Knight says this fern likes a bright or slightly shaded position: 'The Boston fern is really versatile. You can grow it on a north- or east-facing windowsill or in a sunnier room, setting it back a little.' 

'Just make sure you avoid spots in very low light, or in harsh sunshine such as on a south-facing sill.' He also suggests growing them as a bathroom plant, if the light conditions are right, or as a steamy kitchen plant, where humidity levels are high. 

2. Water and feed as required

Make sure your fern’s compost is consistently moist from spring to fall. But, as with many houseplants such as the yucca or Chinese money plant, guard against soggy, wet soil by planting it in a pot with drainage holes in the base. 

Tom adds: 'Mine sits on an east-facing windowsill and I need to water it once a week, sometimes more in very warm weather.' Reduce watering in winter, applying moisture only when the top of the compost feels dry. 

If you are displaying your Boston ferns in a living or dining room, or as bedroom plant, where humidity levels are low, also be prepared to mist the leaves a couple of times a week. Or stand the plant in its pot on a tray filled with pebbles and topped up with water. 

Feed with a half-strength liquid fertilizer once a month from spring to early fall to keep the foliage green and lush.

3. Keep the atmosphere moist

Like orchids, Boston ferns like humidity. The fronds may turn brown if the compost or atmosphere is too dry. Water well, making sure that you don’t overwater. As with pothos care, soggy compost can result in wilting or yellowing leaves and may cause the roots and fronds to rot. 

Ideally, water over a sink and leave to drain before replacing your fern in its waterproof container. If the atmosphere is dry, mist the leaves regularly.

If you find dark brown spots beneath the fronds of a Boston fern, do not panic. These are not a pest or disease but the ‘spores’ by which ferns reproduce, although as per calathea propagation, it is much easier to propagate this fern by division (see below).

Common problems with Boston ferns

Boston ferns suffers from very few diseases and pests, although like philodendrons you might find that mealybugs and scale insects may occasionally attack it. Mealybugs looks like little woodlice and hide beneath a white fluffy coating, while scale look like hard little shells. 

Both suck the sap from plant stems, leading to distorted growth. Try washing off these insects and the scale’s white, waxy eggs with a damp cloth. If this does not work, soap-based insecticides may remove both scale and mealybugs.

Or, for persistent infestations, try dabbing them with a cotton wool bud soaked in a little methylated spirit (test a small area first to ensure it does not harm your plant). This method will work on other infected houseplants including kentia palms and Maidenhair ferns.

Can I put my Boston fern outside?

Christopher Young, leader of the glasshouse team at RHS Garden Wisley in the UK, says that your Boston fern will be happy outside during the summer months. 

He adds: 'Just make sure you place it in partial shade, out of the midday sun. It would also be best to gradually introduce the fern to outside living, by placing it in the backyard during the day, but bringing it back inside at night for a week or two, before putting it out permanently. It should then be okay in temperatures down to about 50˚F (10˚C).'

How do I propagate a Boston fern?

Unlike rubber plant propagation which is done via cuttings, Christopher says that the best way to propagate this fern is through division. 'Divide your plant in the spring, so it can re-establish over the summer months.' 

To do this, water the plant well and remove the rootball from its pot. Then, either use your hands to prize apart rooted sections with the leaves attached, or take a sharp, clean knife and cut the rootball into a few pieces. 

Pot up each new rooted section in a 50:50 mix of fresh multipurpose compost and soil-based compost, in containers just large enough to accommodate the roots. Discard any sections with brown, dried leaves or unhealthy dark-colored roots.

How long does a Boston fern live?

Christopher says: 'I don’t know exactly how long this species lives for, but ferns tend to be long lived, so with careful cultivation they should survive for many years.'

Where to buy Boston ferns

Shop Boston ferns in the US:

• View Boston ferns at The Sill
• View Boston ferns at Amazon
• View Boston ferns at Lowes
• View Boston ferns at Plants.com

Shop Boston ferns in the UK:

• View Boston ferns at Dobies
• View Boston ferns at Suttons
• View Boston ferns at Crocus