Binder is derived, I think, from plantain; comes as a powder which you mix with, say, grass seed and mulch, in order to "glue" the seed and mulch to a slope. Works very well, if you use just a little. Too much and you have a thick crust which the emerging seed will have trouble penetrating.
In theory, the binder should help glue the seedlings into vertical crevices.
This is really in reply to Number 15.....
extreme western edge of Denver, Colorado; elevation 1705.6 meters, average annual precipitation 30cm; refuses to look at thermometer if it threatens to go below -17C
Lee, as a forum moderator I finished adding your photos that you uploaded. You're almost there! All you need to do (in addition) next time to get them to show is have the cursor in the in the text box where you want the photo to be, then click the "insert" button under your already uploaded photo.
And nice photos they are! Thank you!
Rick Rodich zone 4a. Annual precipitation ~24 inches
near Minneapolis, Minnesota, USA
Thanks, Bob. I was looking for a way to look it up (something other than just googling "binder", and that did the trick.
I think in the UK grass seed is mixed with a cellulose wall paper type adhesive when spraying onto roadside banks, but I would have thought a gritty sand/clay mix would be a better temporary crevice filler. The clay will slowly wash out if it is that exposed and hopefully the seedling roots will be doing their job by then. Aggregates used for bedding paving slabs often has some clay content that acts as a binder and might work on their own. The crevice garden at RHS Wisley I think used only gritty sand between the stone "slabs" as a planting medium, after washing any potting composts off the young plants.
You can read about the making of this garden on Kenton Seth's blog, "I Need a Cup of Tea." http://kentonjseth.blogspot.com/
Has anyone tried polymeric sand as a binder? I was thinking if one was using sand and wanted to keep something planted from washing away until it was established, this might be a solution if applied lightly.