Feed and Water Houseplants
Houseplants are actively growing in summer. Feed them with a slow-release fertilizer or scratch some worm castings into the top of the soil for an added nutrient boost. If possible, collect some rainwater to use on houseplants. They love the boost!
Watch for Squash Vine Borers
If some brownish goo is exuding from a squash vine, split it open lengthwise and kill the squash vine borer larva. If you see tiny amber-colored eggs on the leaves or along stems, squish them.
Check Irrigation Systems
It doesn't take long for a non-native plant to die without water in the midst of summer. Make sure the irrigation timer is functioning (sometimes they go out after thunderstorms) and the emitters and sprinklers are working.
The sun's angle is high overhead in summer, and areas that were in shade during winter may now have direct exposure. Most container plants will benefit by being out of direct sun exposure all day.
Palms are one of the few things that actually thrive being planted in the midst of summer. Choose species based on their mature size, both vertically and horizontally, so they don't quickly grow out of bounds. Keep the soil consistently moist, but not wet. This probably means watering daily for the first two weeks, gradually spreading the interval to once per week for the first growing season.