I've heard of people putting them in the bottom of their pots for drainage and to make the pots lighter. I can't imagine them being used for plugs. Try a few just to see if they work!

The cornstarch ones are usually tubular, not S shaped and tend to not snap when you break them. They also tend to flatten when you squish them, instead of compressing and springing to their original shape.

I know this is an old thread but for unrelated reasons, been thinking about this too. My answer - or my hypothesis anyway - is that 'dietary' (human diet) carbohydrates (sugars, pastas, some breads, etc) are mostly being lumped in as 'greens' even when they don't fit the strict C:N framework yard waste is generally looked at in. And I think that's because these starches and sugars are so easily digested that they cause a burst of microbial activity (who mostly bring their own nitrogen i.e. proteins to the party and reproduce like mad, get eaten, return their proteins to the pile as urea, etc). So even if pouring straight sugar onto your compost pile doesn't directly add any nitrogen, it acts more like a green. And if you look at the ways compost manuals talk about the C, it's focussed much more on the cellulose and lignin. The carbs we eat just behave differently (I think part of it is their relative solubility but out of my area of expertise). Or in a dietary comparison: the 'starches' are not the relevant C, but the dietary fibre - the parts human digestive systems mostly can't directly break down, that's the analogue to the 'compost C.' Let's call it compost fibre, since it's not so much the elemental C that impacts how different materials act in a normal compost pile. Caveats: some foods like breads do have more protein in them than we tend to think. It'll depend on what the 'biodegradable things' are actually made of. Other part of this hypothesis might be that because more soluble, they don't keep any structure in pile and act like a lot of the wet greens too, most of which break down faster.

Here is a link to your previous posting of this question - with answers. It was just a bit further down the page. ;) If you couldn't see it then you may need to refresh the page. Dave Here is a link that might be useful: Foam peanuts for shipping...