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Frosts and cold damage on orchids. Re published 27.06.2019 PART TWO. We just had our coldest day in 30 years. So what happens?

Frosts and cold damage. We just had our coldest day in 30 years.
So in South Eastern Australia  we usually break a cold record every 15-30 years.
So that means, unless you have measures in place ,your collection is going to cop a cold bite badly every 15 years.
So what can you do.
1/  Have a carry tray ready every winter to bring inside your favourite gems of orchids ,Avrils Golds ETC
2/ Dont live in Canberra
3/ Have a hard cover over your shadehouse for winter, frost will go through shadecloth.
4/ Dont grow orchids without heavy protection if you live on the INSIDE of the great diving range.
An example of this was 25 years ago at Mandurang Orchids near Bendigo Victoria.
Cymbidiums, Laelias, Sarcochilus and Aussie Dendrobiums all froze to death at minus 7.C
Once it gets that low,there is nothing to do. Even if the frost needle crystals are not present that damage will still be done. The above photos are of extreme cold death and damage.
What else can you do?
5/ Run a fan. Moving, mixed air tends to be a little warmer and frost crytals cant grow.
6/ If your growing area is enclosed, run a small cheap 2kw fan heater. It may cost you $20 in Juice for the night ,but thats better than all the damage a valuable orchid collection mat strike. Keep the heater on a bed of bricks or concrete for extra safety and to create a warmth bank.I have known two collection to be detroyed by these heaters going up in flames. If using an extension cord to reach the growing area,electrically tape the connections.
7/ Have a large fish pond or barrels of water in your growing area. Frosty nights are accompanied by sunny days so the water can heat up and store warmth.
8/ Place a cheap $28 Aquarium heater in a barrel or large container of water.
9/ Never, ever water on a still sunny day in winter!!!  Frosts may come and all that water wont be evaporated by night and will freeze on the foliage.
Water on a windy overcast day. Even if it means weeks without watering
We are currently watering only every 2-3 weeks. Even the weeds wilt. But great roots are produced on the orchids chasing water!
10/ If you live in a colder area dont try to grow Genera not suited to your area.
We use the word Temperate Grower for anything thats needs strong winter protection.
Part Three soon! With the latest photos on the damage.

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  • sally milne on

    I live in Bendigo and have only been growing cymbidium orchids for 4 years . I can keep them alive it’s just trying to get them to spike . What’s the secret? I have them facing north but what am I doing ?

  • Bronwyn stanton on

    I live in Tallong NSW in the southern highlands. We currently have our orchids well protected from frosts but we are thinking the limited light is effecting flower production. If we build a house for the plants what would be the best covering material to prevent frost and allow sufficient light and not cook them i summer?

  • Sue on

    Frost Damaged flower spike on my cymbidium. yes I asked for it Yes I live in Canberra this sadly was the first time I got my orchid to flower and eek I left it under the eaves but -8 hurt badly the spike the leaves looking fine. Question do I cut the flower spike off now or wait. Hope you can help. Suze

  • Ian Broughton on

    Hi Wayne
    I HATE seeing and hearing such horror stories and my heart goes out to all in the nursery industry affected by such damage.
    One small thing: free water on foliage actually gives a degree of frost protection. It’s called the latent heat of melting: turning ice at 0 deg to water at 0 deg requires heat. The reverse applies and freezing water makes heat available to the foliage and gives some frost protection. I used that to good effect in my fern nursery in the Upper Yarra Valley.
    But you do have to keep the foliage wet which means running the sprinklers for short bursts regularly through the period of frost. And another really BIG BUT: you don’t want orchids wet through winter – so that’s not a lot of use to you, and flower spikes will probably be cooked anyway.

  • Newbie on

    Thanks for your info, my glass house was not closed up tight enough and i have had more damage than ever, about 50% of my cymbidium spikes burned off , not sure how to do proceed.

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