The gardening section of About.com helpfully tells us:
... there's no definitive list of gardening chores for the July garden.
Apparently, the problem is that July occupies that netherworld of the calendar, on the cusp between the exuberant growth of Spring and the dog days of August. So, if you are going to intervene in the natural cycles of your plants and lawn in July, you must pay heed to the particular circumstances that confront you. In other words, in July, general rules of gardening should give way to the specific conditions of your yard and gardens.
Not least because we run the risk of hurting more than we are helping,
as we cautioned against here.
Nevertheless, amidst all this uncertainty,
About.com provides a helpful list of chores to keep you busy in the summer heat.
Read the whole thing. As for me, I favor this heat-healthy suggestion:
... sit back and enjoy your garden and all the efforts you put in earlier in the year to get it where it is now.