It happens every year.

We go through a cold spring and cool, moist June then all of a sudden a high pressure system moves in off our coast and beautiful sunshine and hot temperatures jolt us into the reality that summer is here and so is the drought.

For those gardeners that mulch their gardens, the benefit of their hard work is now paying off during the drought. Applying mulch to the garden is the simplest, most economical and most effective way to counteract drought stress on plants. For all you non-mulchers out there I have one thing to say -- a mulched garden weeps no water.

Besides mulching, watering during the summer is one of the primary garden tasks and with watering restrictions in place throughout Metro Vancouver, some gardeners may find it difficult to get all their watering done within the restrictions. The watering restrictions do not affect my garden at all because I have no lawn, and watering restrictions at the current level only restrict the days and times lawn grass can be watered. Anyone can water their trees, shrubs and veggie gardens at any time regardless of watering restrictions. To be truthful, I do have a small patch of grass, but it will be brown soon enough and then my wife won't have to cut it again until fall. Perspective is everything and many people now view a brown lawn as a sign of good environmental stewardship versus the old days of excessive lawn watering in a vain attempt to forestall the natural dormancy period of lawn grass. Brown is the new green when it comes to grass.

We must water our beautiful gardens, veggies and especially trees on city boulevards. Watering trees on city boulevards helps to establish healthy roots systems for our city trees and bigger trees help to shade our roads and sidewalks, which helps to decrease the heat sink effect, thereby cooling our cities.

The recent trend of micro irrigation and drip irrigation that was developed to help conserve water consumption, works for some applications but personally, I do not use micro or drip irrigation. I simply do not believe in the principle of applying localized water right near the base of the plant because it supplies a very limited amount of water to a small portion of the soil. Drip irrigation may work in Arizona or the Middle East where water is limited, or in greenhouse production, but I do not recommend it for general garden watering. Thoroughly watering the entire plant root zone is very important when watering plants. The more surface area you water, and therefore the larger the number of soil particles that are moistened, the longer water is available to supply the plant's needs.

Proper watering should take into consideration the type of soil and its percolation rate (different soils infiltrate and drain at different rates) and the water needs of the specific crop. For established gardens, watering during summer drought should occur once every 10 to 15 days. The watering should be on long enough to penetrate down at least two feet into the soil and preferably deeper, down to three feet. Deep watering may not be possible for some gardens due to varying soil conditions, topography and other factors, but the deeper the water penetrates into the soil and the wider the area covered, the longer the water lasts. Repeat watering should not occur until the water has been used up to the same depth as the water was applied.

For gardens with large trees and accompanying understory plantings, I recommend watering for a long duration, every 10 to 15 days, for at least three hours or more using an oscillating sprinkler or other manual type sprinkler. The purpose of the long duration is to allow sufficient water volume to penetrate deep into the soil, which allows trees to access deep water and understory planting to access shallower water near the surface, thereby preventing competition between the two types of plantings. In-ground irrigation systems cannot typically run for such a long duration due to the large volume of water such systems apply. Therefore, irrigation systems must be calibrated and monitored to apply the maximum amount based on their volume output and soil type.

Watering every three or four days for 20 or 30 minutes is useless, due to the time it takes for sufficient water volume to penetrate to depth in the soil. It can take 30 minutes or more for water to penetrate the plant foliage, mulch and perhaps the top four inches of soil. So short duration watering does not penetrate deeply and accordingly plants will develop roots in the shallow depths of the soil, instead of deep root systems that are found in gardens where deep watering is practised.

stmajor@haw.ca