If your weather is anything like ours (1/2" rain past 3 wks. temps above 90 almost every day), the plants could probably use it. I put the hose on full on one shrub a couple weeks ago and just let it run for a few hours. All of it just soaked in, none of it ran off....
Your garden should be fine. with this heat it will dry up fast.
I did that this year myself. I put the sprinkler on about dinner time in front and forgot about it. I woke up the next morning seeing wetness thinking "Did it rain?". Than realizing holy &*%$ that's my sprinkler. 14 hours or so I had a big bill but the everything loved the water.