"Improving" on an EarthBox?

[Greatgardens]

I have a total of 11 EB's, and really find them very handy, especially for my 70+ year-old knees. But to me they have a weakness of being too shallow. As a result, when you dig into the media 4 or 5" (apx), the mix is downright "mushy." There are several possible fixes for this, but using more perlite is not one of them, unless you would get to the point of having a layer of nearly all perlite close to the plastic grate. A common "fix" is to heap up the mix at the top making a significant "bread loaf" under the EB cover. That certainly helps.

Another idea I've toyed with is to make a "collar" that would raise the height of the box by several inches. The is a limit, of course as to how much wicking you can get, but I really don't believe that would be an issue, since the roots can always go down a bit to get to moisture.

Has anyone ever experimented with ways to increase the depth and increase the area of not-so-wet media? If you have (or just have any thoughts on the subject), what material would you use? I may just try a box or two modified for next year.

-GG