Be water wise

Be Water Wise

By Colin Hamilton

Whether we like it or not, Australia is in dire straits with its water supplies. As a result of prolonged periods of drought, many water collection areas, including the underground aquifer, have not received sufficient run-off for replenishment. But we, as a nation, have kept using water with gay abandon. We are one of the highest users of water per capita of any nation. Now the rooster has come home to roost. We have to take action to conserve our dwindling resources.

I have given the matter some thought and asked some friends from around Australia for their ideas on how to save water in caring for their orchids, and looked at some of the websites advising tips to help mend our wicked ways.

I guess the first and probably most obvious, yet most ignored, is the dripping tap. Leaking taps, pipes and dishwasher hoses is an easy way to reduce water wastage. One leaking tap can waste more than 2,000 litres a month. (Source: Sydney Water Board)
Installing water efficient taps or tap aerators is a great, inexpensive way to cut your water usage without you even noticing.
Mulch your garden beds to retain moisture and lessen evaporation.

Turning to more orchid-specific matters, here are some tips collected from across Australia:

I found that using sphagnum moss as a potting mix or adjunct to a mix can help to increase the time required between watering orchids. Phalaenopsis especially love it. I found that they could be watered here at weekly intervals except in the heat of summer. On warm days I mist them in the morning. They do need repotting annually but their large thick roots make this easy as pie. I also found that small to medium size Vandas and Ascocendas do well with a layer of sphagnum moss in the bottom of the pot. Sphagnum is not recommended for orchids with fine roots as these are too easily damaged when repotting.
For conserving water, one possible way is to use water-absorbing crystals in the orchid mixture - I think they're called Absorber Crystals. They hold the water and then release it slowly as the mixture dries.
Use a wetting agent for all watering. This ensures that the water used 'sticks' in the pot and onto the plant and root system thus saving a lot of water and also allowing greater periods between watering.
After the plants have been watered, plastic under the benches could collect the run-off and run it into drums, filter it and reuse it.
Obviously any rainwater that falls on the rooves of your house, orchid houses, or any other sheds needs to be collected and stored in tanks. Remember the old days when every house had a tank? If so, your age is showing! A friend installed a 4500 litre water tank at the beginning of 2003 purely for watering his orchids.
Multiple small tanks of collected rainwater can be connected together to maintain even levels in each tank. Add a small pressure pump to service foggers, air conditioners and for watering by hand These small tanks can be hidden behind the garage, garden shed, orchid house etc.
I feel some growers will need to look at what orchids they purchase and their water requirements. Many growers have a tendency to water more frequently than is necessary. The time of day plants are watered is also a factor. Many orchids can do with less water than is currently applied, Australian native dendrobiums and their hybrids included. Hot/Cold hybrids with greater than 25% Den. bigibbum influence do not need large amounts of water, as per the needs of the major parent. It may also be necessary to put pots in trays that contain water and leave the rest to capillary action.
The ongoing water situation eventually will prove to be too much if we don't act now. I visualise some growers giving up because of the cost and unavailability of water. Reuse of water will need to be investigated but this is something difficult on a small grower-to-grower scale. Orchid growers, and particularly the professionals, will need to put their case to the relevant Governments to initiate an investigation into reuse of grey water and also reclaimed sewage water.
Another friend has installed three rainwater tanks to collect the water from the roof. For Adelaide's poor water quality, he finds it important to have rainwater for Phals. etc. Also he has his misters on a timer to try to conserve water and to apply it only when necessary.
I think that if you choose a potting medium with materials like moss, peat, vermiculite and perlite, these hold more water in the mix, and you don't have to water as often.
No magic tricks for a friend in Sydney. What he has done over the last few seasons is simply reduce watering to harden his plants by watering less and less often, hand water using a watering can where necessary.

So there are a few views to get you thinking.

Colin Hamilton

Based on an article first published in Orchids Australia (October 2005).