Nephrolepis exaltata ‘Bostoniensis’
How to keep them thriving indoors in Melbourne!
Please Note: The information below is specific to this particular variety. For more detailed notes on the general growing conditions required for all Indoor Plants, check out our ‘Growing Indoor Plants Successfully’ factsheet.
When I finally gave in and succumbed to indoor plants the Boston Fern was the first one to enter the house. I couldn’t resist its easy exuberance. It is such a chameleon: on a pedestal in a vintage pot, it looks perfect in a heritage setting; in a smooth modern pot, it fits naturally in a modern edgy home; works equally well with shabby chic or rustic farmhouse. Nor is it a delicate fussy little show pony, it is as resilient as it is cheerful. A good ‘first plant’ for indoors, giving you success and courage to try a few more!
Adjust watering to suit the season. This is easy, in the warmer months it tends to put on growth and needs more water. Water so that the potting mix is never completely dries out, aim for a nice even moistness. In winter however, allow the surface to dry out slightly before watering.
Bright indirect or filtered light all year round. Avoid direct sunlight as it can scorch the fronds.
Temperature and humidity
Ideally keep between 4C and 30C. Keeping it cooler at night helps avoid fungal problems. It needs humidity, so a humidifier is useful, or failing that misting spray. This is particularly important in winter if you are using central heating. Alternatively, you can put the pot on small stones or blocks to keep it raised, and fill the saucer or slip pot beneath with water. The water evaporates increasing the humidity, but by keeping the pot raised, it allows for free drainage that is essential for a happy indoor plant.
Fertilise monthly in spring and summer with an indoor plant fertiliser diluted to half strength. Only fertilise once over winter and once in autumn. Once a year, flush out any salts that may have accumulated by watering thoroughly and deeply with clean water.
General maintenance can be done anytime. Old, leggy, discoloured or ragged fronds should be cut back to the base. Any major trimming or rejuvenation pruning is best done in spring. They respond well to pruning, giving dense bushy new growth. Boston ferns can grow quite rapidly which is great, except that over time they can become pot bound and this can lead to having to water too often for convenience. If this happens you can simply trim off some of the roots to reduce the size or you can grasp the nettle and repot your fern.
• Best done in spring.
• You can either simply go up a pot size or you can divide the fern into smaller plants resulting in two or more pot plants.
• Use a good quality potting mix and pots with good drainage.
• Make sure your fern is nicely moist before repotting as this ensures the potting mix is adhering to the roots. If you see nodules on the roots – that is normal.
• If simply repotting into a larger pot, go up one size, if you choose too big a pot, then the excess potting mix retains moisture and can lead to fungal problems and root rot.
• If dividing the plant allow it to dry out slightly first. Use a sharp blade (some people find a serrated blade easier) and cleanly slice through the root mass, carefully separating the fronds to get two or more plants. Repot into smaller pots. Trim off any overlong, tired or damaged fronds. This is a good time to really trim back the fern, allowing more good strong bushy growth to develop. Do not plant too deeply into the potting mix, the plant should end up 2-3cm from the top of the pot.
• Pat down firmly (removes air-pockets) and water in well using a weak seaweed solution.
• Allow to settle in for a couple of days in a shady spot, then move to a position with bright indirect light and treat as per normal.
The fronds will eventually age and die, this is normal, but excessive leaf drop is commonly a result of either lack of water or lack of humidity. Occasionally, it can be the result of soluble salts accumulating due to over fertilising. If this is the case you will see white flakes on the surface of the potting mix. Just flush the potting mix with clean water and wash the salts through the mix.
Grey looking plant
Most often due to insufficient watering. Increase your watering. If you are sure your watering regime is good, then root rot may be the problem. If the roots look unhealthy or stunted, treat the plant and soil with an anti-rot fungicide.
If the black appears on the underside of the fronds then this is most likely to just be the normal reproductive spores. Ignore.
o If in direct light, fronds can burn.
o If the temperature is too hot, fronds will brown off
o If drainage is poor, and potting mix becomes soggy, fronds will brown.
o If humidity is too low, fronds can brown off.
o Being pot bound can lead to browning of fronds
o Being physically touched too much. Avoid running your hands through the fronds etc.
o Old fronds naturally turn yellow as they age, before turning brown and dying.
o Overwatering can lead to yellow fronds
o Stress from moving to a new position, being repotted or divided. Allow time for it to settle in.
o Lack of humidity