I did my first 5 gallon all grain last week and had 11 pounds of left over grains that I dumped into the flower pots on the back porch. One of the pots is a half barrel size with a large pepper plant that I dumped maybe 4~6 inches of the grains on the top of the soil. Now, the grains still had a lot of sugar because I only have a 3.5 gallon pot, and the grains started to stick after a few days. I watered the plants really good to try and wash some of the rotting sugars into the dirt.
Anyway, what happened is the pepper plant and a young tomato plant ended up dying on me. All the have fell off and looks terrible.
So could the spent barley grains have killed the plants? has anyone experienced this type of thing mulching with mashed grains before?