On 11 Jun 2011, at 12:24, J.E. Shields wrote: > Plants normally take up only the amounts of nutrients that they need. The operative word is "normally". Some plants that have evolved where certain nutrients are in short supply have highly efficient mechanisms for extracting those from the soil - and if there's too much (i.e. a normal amount), they're like heroin addicts with overly pure horse and overdose. Examples: rhododendrons, which scavange calcium overly efficiently, so can't handle soils with much of it. South Africa proteas, which are native to very low phosphate soils and are sickened with too much phosphate. So keep that in mind, that Jim's "normally" means "and there are exceptions." I'm not aware that amaryllids are exceptional in this way. -- Rodger Whitlock Victoria, British Columbia, Canada