How to Grow Boston Fern
Nephrolepis exaltata
Boston fern produces lush arching fronds and thrives in bright indirect light with consistently high humidity. Mist daily or place on a pebble tray with water, and use rainwater or filtered water to avoid brown tips caused by fluoride. Keep above 10°C, water frequently to keep the soil evenly moist, and feed monthly in spring and summer. One of the best ferns for hanging baskets and humid rooms.
Yearly Lifecycle
Care Essentials
Feed monthly with half-strength balanced fertiliser from spring to early autumn. Do not feed in winter when growth slows.
Watch For
- Scale insects on frond undersides
- Mealybugs at frond bases
- Brown frond tips from dry air or fluoride in tap water
- Root rot from waterlogging
Track your Boston Fern care schedule — pruning, feeding, and seasonal tasks
Start planning freeCare Requirements
☀️ Light
Bright indirect light; no direct sun.
A north- or east-facing windowsill is ideal. Direct sun scorches fronds; deep shade produces sparse, pale growth. Move back from a south-facing window to avoid afternoon rays.
💧 Watering
Keep soil consistently moist but never waterlogged.
Water thoroughly when the top centimetre of compost begins to feel slightly dry, then allow excess to drain freely. Use rainwater or filtered water to avoid fluoride-induced tip scorch.
🌱 Fertilizing
Monthly half-strength balanced feed, spring to early autumn.
Apply a balanced liquid fertiliser at half the recommended strength once a month from March to September. Do not feed in winter when the plant is resting.
✂️ Pruning
Remove dead or brown fronds at the base as needed.
Cut individual yellowed or fully browned fronds back to the crown with clean scissors. Light tidying can be done year-round; avoid cutting into healthy green growth.
🌿 Humidity
High humidity is essential — 50% or above.
Place the pot on a pebble tray filled with water, mist fronds daily, or use a humidifier nearby. Low humidity is the single most common cause of browning frond tips in centrally heated homes.
Growing Tips
Boost humidity with a pebble tray
Set the pot on a tray filled with pebbles and water, keeping the base of the pot above the waterline. As the water evaporates it raises the humidity around the fronds without waterlogging the roots.
Use rainwater or filtered water
Tap water contains fluoride that causes brown leaf tips over time. Collect rainwater or use a filtered jug to keep fronds looking their best.
Bright indirect light only
Direct sun scorches the delicate fronds; deep shade causes sparse, pale growth. A north- or east-facing windowsill, or a metre back from a bright south-facing window, is ideal.
Repot in spring when roots fill the pot
Move up one pot size each spring using a peat-free houseplant compost mixed with perlite. Boston ferns prefer being slightly pot-bound, so do not overpot.
Pests & Diseases
Pest Scale Insects
Identification: Brown or tan oval bumps on frond stems and undersides; sticky honeydew residue on leaves below.
- Scrape off with a soft toothbrush dipped in soapy water; repeat weekly until clear.
- Apply neem oil solution to affected stems, avoiding new growth.
- Systemic houseplant insecticide containing acetamiprid applied as a soil drench.
Pest Mealybugs
Identification: White cottony clusters at frond bases and leaf axils; leaves may yellow and fronds wilt.
- Dab colonies with a cotton bud soaked in rubbing alcohol.
- Spray with a dilute insecticidal soap solution, ensuring good coverage of frond undersides.
- Systemic insecticide drench containing imidacloprid for persistent infestations.
Pest Fungus Gnats
Identification: Tiny dark flies hovering around the compost surface; larvae are small white grubs in the top few centimetres of soil.
- Allow the top 2 cm of compost to dry between waterings to break the larval cycle.
- Apply a biological control drench of Steinernema feltiae nematodes (available in UK garden centres).
- Imidacloprid-based compost drench labelled for use against vine weevil also controls fungus gnat larvae.
Disease Root Rot Pythium spp. / Phytophthora spp.
Symptoms: Fronds yellow and collapse despite moist soil; roots appear brown and mushy rather than white and firm.
Treatment: Remove plant from pot, cut away all brown roots, dust cut surfaces with sulphur powder, and repot into fresh free-draining compost. Reduce watering frequency.
Prevention: Always use a pot with drainage holes; never allow the plant to sit in standing water; water only when the top centimetre of compost begins to feel slightly dry.
Disease Frond Tip Scorch Physiological — fluoride/salt toxicity
Symptoms: Brown, dry tips progressing inward along the frond margins; no pest visible and the rest of the plant looks healthy.
Treatment: Flush the compost with large volumes of rainwater to leach out accumulated salts; remove badly affected fronds at the base.
Prevention: Always water with rainwater or filtered water; avoid over-fertilising — use half-strength feed only.
Log Boston Fern in your garden — track growth, care, and harvests year after year
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