[Crowbob]

I'm a fan of Milorganite.

Milwaukee owns the patent on repurposed sewage. Really good stuff but you need a ton of it and it's not so cheap. 6% N but with a ton of micronutrients like Fe (iron). Can't burn anything, slow-release and smells like, well you know what it smells like.

It takes a while to show results but it is feeding the soil, not the plants. I put it in the broadcast spreader and am completely unconcerned about where it goes (except for the deck and patio) any time of the year, as often as it's on sale. Over time it's made a huge difference.