How to grow Cool Climate Orchids
How to grow Cool Climate Orchids. Clive and Agi Halls are orchid specialists. In this article Clive and Agi provide some general notes on orchids as well as some ideas on orchid care. Clive and Agi run Mt Beenak Orchids, specializing in cool climate orchids.
Cool Climate Orchid Culture by Mt Beenak Orchids
The orchids we sell at Mt. Beenak Orchids are cool growing epiphytes, that is they come from high altitude, or cooler low lands and typically grow on trees, rocks, stumps etc., not in the ground.
Although different species may require a variety of cultural needs the basics remain quite consistent.
As epiphytes which in nature have their roots exposed or just lightly covered we must always attend to good drainage & freshness of the potting mediums. Wet, decayed and acidified medium whether it be bark, moss or peat will cause your plants root system to decay. New roots will try to grow but die as they contact the acid mix. The plant will shrivel often leading you to think it is dry and water it even more, compounding the problem. Eventually the orchid deteriorates and dies. The good news is that all this takes time and you can take remedial action in the form of re potting in fresh potting medium.
Orchids will give you visual indication of root deterioration in a variety of ways:
Bulb shrivel. Green lead bulbs should remain plump & only show signs of shrivelling when in flower.
Yellow leaves. Plants will generally drop some leaves on back bulbs particularly in Autumn. Yellowing leaves on lead bulbs should be a warning.
Leaf Tip Die Back. This often indicates poor roots but can be genetic or fungal. If it is wet looking and brown suspect the roots. If black and there are also spots suspect fungal problems and spray a fungicide.
Potting mix dark green and slimy. This can just be on the surface in which case scrape off and top up. More often though the whole pot is wet and soggy, the roots mostly brown and soft. This can happen in less than a year from the last re potting. You should expect bark to last 12 – 24 months but due to composting techniques you can’t always guarantee this will be so.
Mix does not dry out. Your potting medium usually dries out in 1-2 days in warm weather , 5-6 days in cooler times.Never be frightened to knock the plant from the pot to have a look & see.
Unless you are repotting because of decayed medium as just discussed, stick to Spring or Autumn with Spring being the best choice.
Use either Orchid Potting Mix or Sphagnum Moss. Buy only recognized brands such as Bio-Gro, Propine, Debco, Austmoss.
Orchid Potting Mix is graded, small, medium, large and may have coarse sand added. We usually recommend small grade up to 125mm pots, medium for up to 250mm, large there on. If possible screen out dusty material in a 3mm sieve.
Choose a pot just large enough to contain the roots and leave enough room for 12-18 months growth. You may need to twist the pot so the roots sit nicely and don’t get broken. Keep the base of the bulbs just about rim level and fill the pot with bark, tapping lightly to make sure the roots are evenly infiltrated.
As you go tap the pot on a hard surface to firm the bark. You must anchor the plant firmly. If there were little or no roots you may need to fix it to a short stick. Water in until water runs through the pot.
Sphagnum Moss. If purchased in dry packs, soak overnight and squeeze out excess water or allow to drain until light and fluffy. Do not use while wet.
Long strand moss is easier to use if chopped into 25mm length. Moss may be mixed with up to 50% polystyrene crumble. This prevents over watering and over compression while potting, it also makes the moss go much further. If you don’t use polystyrene don’t compress the moss too tight in the pot and be careful not to over water.
Moss Potting: Firm moss with fingers easing between roots. Do not over compress moss but make sure the plant is well anchored in the pot. Water lightly.
Use pots with plenty of drainage holes and only use a pot just big enough to allow growth for 12-18 months. You can use tall pots or squat pots. Cymbidiums & Zygopetalums in larger sizes do better in tall pots.
Native Dendrobiums and Sarcochilus prefer squat pots.
When repotting you may need to divide but do this only if you can make 2 or more reasonable size plants. As a guide Cymbidiums not smaller than 3 green bulbs and growth, Masdevallias 7-8 leaves, Odontoglossums 3-4 leaved bulbs and growth, Zygopetalums 2-3 leaved bulbs & growth, Native Dendrobiums 4-5 canes, Sarcochilus 4-5 canes.
Remove all dead roots. These are soft brown or black, cut back to base of plant. Cut broken roots behind break. Remove back bulbs with no leaves. These usually have dead roots attached. If you cut these out first you will find much of the work done.
Clean up all dead leaf bracts, dead canes on Dendrobiums, trim dead leaves. Wash roots if they are muddy from very old decayed mix, otherwise not.
Pests & Diseases: Not many nasties but watch out for scale – white or brown on underside of leaves. Remove and spray with Malathion or Rogor.
Red Spider Mite: Appears in late Spring. Looks like pepper spots on underside of new growth. Severe infections turn underside of leaves silver and reduce growth dramatically. Use a mitecide such as Master Mite or Kelthane
Fungal & Bacterial: Good air movement is the most important factor in keeping fungal infections at bay. Remember some symptoms may be related to root loss. Good sprays are many but a good general purpose is Mancozeb
Slugs and snails: They destroy a years work overnight if you are unlucky. Flower spikes can be protected with cotton wool wrapped around the base of the spike. Cleanliness and removing all dead material is essential. Even when growing plants on wire mesh benches you may still need to use Baysol pellets or similar.
We recommend you grow our cool growing orchids in a position with morning sun, followed by dappled light. Keep the plants under cover in winter so you control the watering. And remember: Cold & wet is bad.
Clive and Agi Halls
Mt Beenak Orchids
19 Hackett Rd Three Bridges VIC 3797
To view Mt Beenak Orchids Catalogue follow the link below
For more information join your local Orchid Club or subscribe to Orchids Australia or The Australian Orchid Review.