Top Dressing Dr. Earth

Dry amendments are feed once every 3 weeks"most brands", they only need ph'd water going in. Depending how processed the amendments are and its particle size will plat a factor in determining how fast it will breakdown. Somethings break down faster or slower and other things that influence are heat and other microbes present in the soil. I would recommend a booster of microbes anytime you fertilize. Good note below on feeding autos with regards to hot soil. Been there done that, use less vs more. Good Luck

I would look at their recommendations. With the fox farms dry organic nutrients it's 1xmonth

I'd wait a week... I'm not sure if you have seen it yet but 420 fast buds has a blog with tons of autoflower info. There's a specific feeding schedule they reccomend. But basically with autos dont give the recommended full dose. I've been top dressing with earth worm castings myself. I hope this helps! Just cut those doses. I'd say wait a week and a half and maybe top dress the same amount it you don't have any nutrient burning. I've run some hot soil on autos.