On The Brink

Another hot, windy, intensely sunny day in Brisbane. I’m getting used to watering whilst holding an umbrella because with low humidity and few clouds the UV is really extreme.

The rainwater tank has about two days worth of water for household use left. We’re producing about 350 litres of recycled water a day, well short of what is required for sound cultivation, and insufficient for survival watering for all our crops and fruit trees.

Dust Storm over Wynnum, 30th November 2006
Dust Storm over Wynnum, 30th November 2006

This October our garden received 6mm of rain (the 50 year average is about 95mm). November looked promising when we received 71mm (the 50 year ave is about 95mm), but windy weather took most of that back. So far we’ve received 39.5mm rain this month with the 50 year ave being 120mm. That’s 116.5mm instead of an anticipated 210mm…

Despite water saving actions late last month, including three minute showers, I’ve drawn up a list of further cuts to reduce water consumption. I count the watering times for each plant. The rate of flow from the recycled water pump means that by counting to fifty the hose delivers 5 litres, so projected watering savings are noted below. These will be enacted as soon as possible.

1 Planting out of potted stock:
This helps to reduce watering because potted plants need watering more frequently than plants grown in open ground. Pots and potting mix heat up and dry out quickly in summer:

* Pot up twelve of the best White Cedar seedlings, Melia azederach ssp. australasica, and put the remainder onto compost heap. Watering twelve pots three times weekly will use 3.6l needed a week instead of 4.2l for watering one seed tray daily;

* Plant out one pot of the succulent Kalanchoe orgyalis. Watering once weekly uses 0.2 litre saved;

* Plant out one pot of the succulent Glottiphyllum. Watering once weekly uses 0.2 litre;

* Plant the single cutting of Euphorbia caerulescens in the pot with its parent plant. Watering once weekly uses 0.1 litre;

* Plant out last Bunya pine. Watering one plant three times weekly uses 1.5 litres;

* Plant out cuttings of Pollia crispata; Watering six pots three times weekly uses 2 litres;

* Plant out four Queensland Bottle trees; Watering five plants three times weekly uses 22.5 litres;

* Plant out two ornamental pineapples. Watering five plants four times weekly uses 8 litres;

* Give away or sell one Polyalthia, two Prumnopitys ladei, one Alloxylon flammeum, one Ginkgo biloba and one Pandanus veitchii; watering these uses 22 litres weekly;

These actions will save 56.9 litres of water per week.

2 Use shade to reduce watering.
This reduces the rate of evaporation:

* Move crotons, Codiaeum variegatum, into semi-shade. Watering eight plants five times a week uses 40 litres;

This action will save 40 litres per week.

3 Remove plants to cut water use.
Two of the eight vegetable beds are unplanted and a third, growing the sweet potato, has been watered once only since August.

* Remove half of the mangelwurzel and eat as much of these as possible. Watering twenty plants five times a week uses 100 litres;

* Remove the two luffa plants. Watering two plants five times a week uses 20 litres;

* Remove one young passionfruit vine. Watering one plant three times a week uses 12.5 litres;

* Remove half the chillies, and store what’s ripe. Watering twenty five plants seven times a week uses 175 litres;

* Remove half the parsley. Watering one row seven times a week uses 31.5 litres;

* Remove and eat the last of the taro. I had six cultivars and while this was the best and least water-demanding of the lot it still needs frequent watering to survive. Watering seven times a week uses 26.25 litres;

* Remove four out of seven zucchini plants and eat the fruit. Watering seven plants seven times a week uses 98 litres;

* Remove one of three pumpkin plants. Watering three plants seven times a week uses 42 litres;

These actions will save 505.25 litres per week.

4 Thin plants so that those remaining have more water for growth:
I’ll thin out the okra, reducing them from three rows to two. Wherever two seedlings have germinated in spaces allocated to one plant, remove the weaker plant from the two rows to be kept;

This action will save 31.5 litres per week.

5 Reduce watering frequency of recently transplanted lemongrass and cardamom:
Not much of a saving here as the cardamom have only been watered twice since transplanting two weeks ago. I wouldn’t have moved them had it not been necessary to create space for repairs to the rear steps, because transplanting creates stress for plants in hot, dry weather. The seven clumps have been receiving 24.5 litres per week. The six lemongrass have been receiving 36 litres per week.

This action will save 60.5 litres per week.

6 Cut down plants to temporarily reduce water consumption.
I’ll cut down the Moroccan mint again.

This action will save 20 litres per week.

7 Cease watering food plants that are ready to set seed, or are easy to restart, hastening their demise:

* The Huauzontle – we can eat the best shoots. Watering five times a week uses 25 litres;

* The Warrigal greens after taking some tip cuttings. We can eat the best shoots. Watering five times a week uses 37.5 litres;

* The choko. Easy to replace and we can eat the shoot tips. Watering five times a week uses 17.5 litres;

These actions will save 80 litres per week.

Total recycled water available for whole garden per week is 2,450 litres.

Total projected savings per week are 794.15 litres.

Showers and rain are forecast from Christmas day onwards, so things may ease a bit. I’ll have to consider ceasing watering the Hibiscus insularis hedge in the front garden, risking it’s survival. I’ll also skip watering whenever I can should we get any cool, cloudy conditions – one such day occurred last week.

The front garden, bamboos and George’s lawn are surviving OK without water, the pineapples, cocoyams and yams are surviving without watering and grow a bit each time it rains, but the main compost heap is becoming mummified – it’s too dry to decompose well.

These are the sort of challenges that will face residents, businesses and government during 2007 as SE Qld prepares to run out of drinking water. This household is lucky to be so closely connected to the water crisis and these actions will keep us ticking over for the time being.

Jerry Coleby-Williams


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