I can't remember what it was,(phosphate of something I think)
I put it round the base of my Rhubarb,and no word of a lie,the rhubarb shot up to seven feet high,and had masses of seeds on it.
Apparently,every seven years,rhubarb shoots up and seeds,but I don't think it normal to grow to seven foot high.
It's been in the garden for nearly 20 years,and it's the first time it's seeded.