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?
Spent grain has a fairly high nitrogen content. It’s entirely possible that using too much of it could harm the plants, just like “burning them out” on a high-nitrogen fertilizer.
The grains were still a little hot when putting in the pots, so I think maybe the smaller tomato was effected but the pepper was a big bush with inch thick base so not likely. Too much nitrogen or PH change is possible.
Guess the lesson is: compost your grains first before adding to plants
Spent grains and most other stuff really needs to be completely composted before it’s good for plants. I killed a tree a few years ago with uncomposted stuff because I grew up in Mobile Al and leaves and other stuff fall and decompose into very rich soil. Apparently falling is the critical step because when I just put fresh leaves, grass clippings and spent grains on the ground it killed the tree.
