So am I - just popping in to be sure of seeing any replies.

Yes that's one I'd like to keep track of, its an interesting idea....

Certainly sounds interesting - I hope someone replies who has experience of this!

An organic gardener told me about this some years ago when I was into home-brew, so I used to throw all the spent yeast onto the garden that was in the bottom of the brew bin when the beer had finished fermenting. I gave some to my neighbour and his roses did very well.

The organic gardener said he made up an organic fertiliser mix with brewers yeast, animal dung, seaweed, and something else that I can't remember now. Apparently it increases micro-organism in the soil and yeast can be added to a compost bin as well as pee to speed up the compost process.

Yeast is one of the ingredients in Bokashi bran, if you're using a bokashi compost system.

Brewers yeast, diluted in water, is supposed to initiate bud formation in roses, never tried it, but that's brewer's yeast, not sure if its different from baking yeast.

I don't know of any benefits of using baking yeast on its own except for one thing - yeast produces carbon dioxide, and plants use carbon dioxide in photosynthesis. Even so, I can't see how a lot more carbon dioxide helps, the plant uses carbon dioxide in ratio to water and light, so having more of it about, especially when there's plenty in the atmosphere, doesn't seem like a good explanation for yeast on its own being a good fertiliser. I'll be interested to follow this thread - where's Seaburngirl when you need her;-))

I don't think it's so much to do with CO2 but more to do with the yeast feeding on the sugars in the traces of vegetation in the soil and breaking it down into useful plant nutrients.

Best thing to do is feed one rose with yeast and see if it grows better than the rest. Then let us know!

Thanks for all the interesting answers to my question. I might try dried yeast to see if my cucumber plants will grow...they have been outside for about a month and don´t seem to want to grow anymore.