The Canadian Wildlife Federation has lots of useful tips for seasonal gardening.  Here is what you should be doing in mid to late summer!

Wildlife

• Prepare a snake den or toad hibernaculum for overwintering amphibians and reptiles.
• Top up ponds during dry spells.
• Clean hummingbird feeders and change nectar often in hot weather. Learn about the beautiful native plants you can include in your garden to attract them.
• If skunks are digging up your lawn to get at grubs (actually a very useful form of insect control), rake the grass back in place and water it. The grass will grow to fill in the spots. For serious grub infestations you can use applications of nematodes (microorganisms that eat grubs) instead of poisons, which can harm beneficial insects like pollinators and insect-eating birds like hummingbirds.
• Check your garden regularly for signs of insect damage and avoid using pesticides.

General Gardening Chores

• If your water supply is limited, you may safely let your lawn go brown. This is a natural and protective dormancy. Grasses have evolved to survive summer droughts and will revive in rainy, cooler weather.
• If you use sprinklers to water the garden, do so in the morning to help prevent water loss from evaporation. Additionally, foliage left wet overnight is more vulnerable to mildew, fungus and disease.
• Water container plants daily and fertilize every two weeks.
• Continue to inspect plants regularly for signs of insect infestation or disease so you can take quick action when necessary.
• Turn your compost pile.
• Maintain your grass at five to seven centimetres high to better withstand drought and compete with weeds.
• Prepare beds for fall planting by adding compost.
• Remove faded flowers to encourage second blooming for plants such as purple coneflower and bergamot.
• Prune unwanted shoots on trees.

Planting

• Avoid moving plants in the heat of summer. Mark the plants that need to be split or moved so that you can identify them once cooler fall weather comes.
• Mildewed summer phlox should be replanted in an airy location with good wind.