I made the same mistake I've made more than once... again!
I planted out some cool-season annuals a week or so ago to enjoy while my warm-season seedlings mature. Made the mistake of thinking it wouldn't go straight to broiling hot from the high thirties...so, I didn't mulch right away. Yesterday I really had to scramble to get it done...
All of today's transplants did get mulched right away! The ones in full sun with logs...