Aug 162009
 

Photo © Bulleen Art & Garden

Adiantum spp.

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.

The Maidenhair fern is surely one of the most delicate and graceful of ferns. It somehow combines cool and ethereal with lush and gorgeous. To see a big beautiful maidenhair is to covet one.
They are much easier to grow than you think, without many requirements; but those it does have need to be met. The key is finding the exact right position, if you have that, you are 90% of the way there.

Watering

Adjust watering to suit the season. In the warmer months it tends to put on growth and needs more water. Water frequently so that the potting mix never dries out, aim for a nice even moistness. In winter keep moist, but not over-wet, it will need less water.

Light

Bright indirect or filtered light all year round. Can take a bit of direct very early morning light but avoid any more direct sunlight – it can scorch the fronds. Will not tolerate a dark position.

Temperature and humidity

What they don’t like is large fluctuations in temperature and humidity. They prefer consistency (hence enjoying terrariums) and sulk if moved. Keep out of draughts. Ideally keep between 10C and 30C. They need humidity, so a humidifier is useful, or failing that, a misting spray. 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 humidity, but keeping the pot raised allows the free drainage essential to a happy indoor plant.

Fertilising

Fertilise fortnightly in spring and summer with an indoor plant fertiliser. 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.

Maintenance

General maintenance can be done anytime. Old or tatty fronds should be cut back to the base. Any major trimming or rejuvenation pruning is best done in spring.

Repotting

• Best done in spring.
• You can either simply go up a put size or you can divide the fern into smaller plants resulting in two or more pot plants.
• Use a good quality potting mix with water retaining crystals in it, 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.
• When replanting it is essential the crown is left above the soil level.
• If dividing the plant, allow it to dry out slightly before undertaking the task and 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.

Problems

Leaf Drop

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.

Black fronds

If the black appears on the underside of the fronds then this is most likely to just be the normal reproductive spores. Ignore.

Yellow fronds

• Old fronds naturally turn yellow as they age, before turning brown and dying.
• Overwatering can lead to yellow fronds
• Stress from moving to a new position, being repotted or divided. Allow time for it to settle in.
• Lack of humidity

Mealy bug

Spray with white oil or pest oil.