posted 3 years ago
okay, I can speak to a few things here (we do rabbits, sprouting, and coffee!!)
First, coffee grounds and rabbits go well together. I learned from a local rabbitry to use coffee grounds to absorb urine under the rabbit cages, and even to spread it in areas within their hutches where they urinate (it completely eliminates any smell, and makes excellent compost). Where it is in their cages (i have one female who likes to wee in the corner of a "room" in her hutch on top of a wooden molding), they leave it alone. Don't eat it, lick it, whatever, it's neutral to them (I wouldn't want them standing in it as bedding, i don't think, but otherwise it's fine).
As for sprouting, I haven't done it in a while because I'm in high summer and there's plenty of forage, but come winter in June I'm sprouting food for the bunnies.
I keep old potting soil around specifically for mixing bokashi and sprouting medium, but any old dirt will do if you have any (and I use a TINY bit-- just enough to cover the bottom of the tray).
And as Anne says, you don't even need it, depending on what you're sprouting. If I'm growing sunflowers, peas, or maybe lentils I'll use some sort of substrate- dirt, compost, or even newspaper! Smaller things, I might not even bother. I would seriously use whatever I had.
This may vary depending on how many rabbits you're feeding, and what kind of plants you're sprouting. What are your plans?