Record-low water levels in Vancouver’s water-reservoir system are leading to restricted water-use for this region’s homeowners, and therefore brown lawns.
Earlier this week, Metro Vancouver declared that Stage 3 water restrictions were in effect immediately, and that lawn watering, pool filling and car washing was prohibited to conserve the public’s water resources.
Under the Stage 3 water restrictions, no watering of residential or non-residential lawns is allowed; no outdoor washing or rinsing of cars or pleasure crafts like boats (except for safety such as windows, lights, licenses, etc.) is allowed, nor is the refilling of private pools, spas and/or garden ponds.
However, watering flowers and vegetable gardens, decorative planters, shrubs and trees is allowed if done by hand only.
And experts say there’s no respite from this water shortfall in sight with more than 260 additional millimetres (mm) of rain needed between now and the end of September (this area only gets a little more than 120 mm of precipitation usually) to top up Metro Vancouver reservoirs.
So how will these water restrictions affect your lawn?
Most grasses can tolerate a certain level of dry spells. But even the hardiest of grass types need water and, in desperate times, can show signs of drought stress.
Because water carries and spreads grass’ nutrients, your lawn can fade and even die if water is lacking.
The first sign your lawn is suffering drought is the obvious faded appearance.
Healthy, watered grass has a vibrant colour and durable stiffness. And healthy grass, when depressed, quickly regains its vertical posture. But drought-stressed lawn doesn’t snap back up, instead it lies flat when stepped on or pressed down.
Longer-bladed grass species (i.e. bluegrass or fescue) will be the first to fade and flatten while shorter-bladed grasses (ryegrass and centipede grass) tend to maintain their shape and color longer.
Longer periods without water will cause grass to wilt; an indication of heavy stress on a lawn’s grass and experts say it needs to be remedied immediately.
And experts suggest homeowners do not mow their lawns when stringent water restrictions are in place.
Grass with longer blades have more surface area to store moisture and can continue to absorb sunlight; maintaining the photosynthesis process. So wilted grass can still be salvaged.
It is suggested that homeowners always mow their lawns at the highest recommended height for their turf species to increase blade area and allow for more photosynthesis, and help it survive stresses like drought. The higher the mowing height, the deeper and more extensive the root system will be.
One should never cut more than one third of the leaf blade at a time. This will reduce needed mowing frequency as the grass will grow slower during drought.
Because soil dries out inconsistently, some parts become arid before others, and lawns die in patches.
Brown lawn patches will occur first in grass species with shallower root systems, such as bent grass and later in deeper-rooted grass types like perennial rye.
Obviously if the ban on lawn watering continues for too long, lawn grass can die. Ryegrass and meadow grass are naturally better adapted to low-water conditions and can go longer than more domestic and colorful species like St. Augustine or Bluegrass.
And once the majority of a lawn’s grass is dead, it will need replanting.
Reseed your lawn after the water restrictions and drought conditions have abated.
And fertilizing during drought periods should be reduced or postponed. Nitrogen fertilization encourages grass to put its energy into growing shoots rather than roots, which prevents grass from developing the deep root system it needs to survive and creates new grass blades that will suffer from the drought.
If you do choose to fertilize, try to use a product that slowly releases nitrogen.
A fertilizer with a high potassium can help enhance drought tolerance.
And going forward, for summers to come, it may be worth considering a rainwater-collection system that would allow you to continue watering during periods of water-use restrictions. But that’s a topic for another column.
Kevin Gillies is a freelance writer for Black Press.