Taken from Eclectic Gardener @ www.teachinggarden.org
Written by Alan Hickman

With the dog days of summer upon us, the parking lot garden centres are packing up their tents and disappearing into the night. For them, like many of their customers who buy a few annuals to plant like a wreath around the front lawn tree and then depart for the cottage, the gardening season is over.

For the rather smaller subset of the population, those for whom gardening provides a year-round interest rather than just being another spring chore, the 2008 garden season is just starting to get a good head of steam. The spring flush is over, the blooms of high summer are beginning to show, and the asters and goldenrods are building up their reserves ready to explode with colour in a couple of months’ time.

Although the past two years have been horribly dry, this year we’ve had some good rainfalls and, so far, reserves of soil moisture have really been quite reasonable.

Preparation is the key to conserving what nature has provided. At the Teaching Garden, the almost constant wind sucks water out of the ground wherever the surface is bare. The beds which were heavily mulched, either with last year’s shredded leaves or with old straw, have remained mostly weed-free and moist enough for planting. The beds which didn’t get mulched are simply a mess; weeds literally shoulder-high and soil as dry as a brick.
Unless we have a very wet year, however well the surface is mulched, the shimmering heat of summer will eventually deplete the soil’s available moisture reserves and the more vulnerable plants will start looking sad. In most gardens at least some supplementary watering is inevitable, but there is little excuse for the gross waste of water which one sees in most neighbourhoods.

The most obvious economy is to water only those plants which are showing signs of distress. Given the size of what is now a typical subdivision garden, the first few plants that show drought stress can be aided with nothing more complicated than a half-bucket of water poured over their roots. No hose pipes, no timers, no sprinklers. If you carry the water down the garden in a bucket you’re much less likely to pour it where it is not needed!
If you are hand watering, you will also find out where the drought-vulnerable plants are. If they are scattered hither and yon about the lot, it might be a good idea to dig them up and put them all in one place so that they can be kept moist together.
I have a few moisture-loving ferns which have ended up being planted around the front stoop. A couple of times a day, when the dogs’ drinking water needs changing, the water dish gets emptied over the rail and onto the ferns and hostas below. The plants thrive and the water doesn’t go down the drain.

At the other extreme, from watering single plants, is the lawn. Southern Ontario has hot summers and grass is a cool season crop. Grass is supposed to go brown and dormant when soil moisture drops and temperatures reach the high twenties and thirties. Leave the lawn alone and it will come back thick and lush when the fall rains arrive. A brown lawn says that you care about the environment.

To some extent, drought and heat induced dormancy can be delayed by cultural practice. Cut the grass with the mower blade at least 3" above the surface. The longer the grass, the fewer times it needs to be cut and the deeper the roots will penetrate into the soil. The further down the roots are, the more time they will have access to adequate soil moisture. Don’t keep pouring fertilizer on the grass. An abundant supply of nutrient reduces a plant’s need for feeding roots, and simply makes the plants soft, lazy and more vulnerable to environmental stress.

If you can’t leave well alone, at least water somewhat efficiently. The rule-of-thumb is 1" of water per week, but few people seem to have any idea what that actually means. If the water is flowing at a rate of 300 gallons an hour - about what an unrestricted outside faucet might pass - it would take about a quarter hour to get one inch of water on a lawn twelve feet square. It might just about be practical to hand water such a lawn using an open-ended hose or a wand that offered very little flow resistance.

People who wave around a hand-held squirter, with water spraying out of one little hole, are just wasting water to no effect. Most of the fine spray evaporates or is blown away and the total flow is so low that it would take hours to get an inch of water actually onto the ground.

A similar principle applies to mechanical sprinklers. The smaller the hole and the finer the spray coming out of the nozzle the less effective and more wasteful it is. Likely, the least wasteful machine is one of the oscillating devices with multiple coarse jets. The coverage is uneven - more water is applied at each end of the swing than in the middle - but, if it’s set-up so water isn’t running on half the driveway or down the sidewalk, the oscillating sprinkler is about as efficient as anything gets that throws water into the air.