I can't remember where I saw some postings of how some people put the fertilizer in a porous "sock" instead of directly on the soil in a strip. Has anyone tried this, if so what material did you use and did it work? I think it would help greatly to remove the used fertilizer when prepping the box for a new planting. I'm going to hunt down some soft mesh or tulle-like material to wrap it into. What do you think?

I do that, and it makes it much easier to remove the fertilizer - in a trench, it seems to spread out, and sort of make a mess, when it comes to "topping off" the tubs in the spring. I got a bunch of brewer's socks - something that I got on ebay - and they last through two seasons. I cut one end open, add some more fert, then tie it shut again. In the bucket SIPs, I make smaller ones, with just 1/3 c/sock, and 2/bucket, add 1 the second year, then remove the old ones - it's easy to spot the old ones, as they are darker, and starting to decompose a little, but still holding together.

Update: after posting this, I remembered when I was uncovering all of my SIPs the last two days, and pulling the roots out, only a few of the varieties were still not wanting to come out! (I cut the ones that don't come out at the slightest pull to a short stub, and most pull out easily, come spring). And one of them pulled so much out with it (most aren't that hard to pull up in the fall!), that part of the fertilizer sock came up with it, at least part way. I figured I'd take a photo of it, and a photo of the new ones, as well, to show what they are. The roots grow through the socks, sometimes, but don't really destroy them - they still last at least two seasons.
Part of a fertilizer sock in an EB. by pepperhead212, on Flickr

Bag of brewer's socks, showing one unfilled by pepperhead212, on Flickr

The sock is a little over 2', so it fills an EB in almost the whole length of it.

[mention]pepperhead212[/mention] what material is it made of?

@peebee It's listed as cotton muslin, but that's a sort of vague term. Here's a link, showing some photos of the same type I have:

[mention]pepperhead212[/mention] thanks!