Posted: 21/03/2017 at 21:47
Well anything in large doses could be a hazard. The the idea with Ferric phosphate is that the molluscs crawl away & die so are less likely to be picked up by birds hedgehogs etc If used sparingly the ferric phospate should breakdown in the soil. I would love to be able not to use these things at all but when it's a case of keeping a crop or bed full of plants for me its a last resort but I will use them. Last year was particularly bad for slugs, I was helping with a schools garden & one week we planted out some lettuce we had grown in modular cells ourselves. The following week there was only bare earth even the stems had gone. This happened 3 times,then I resorted to pellets round the outside of the deep beds at last the children had some lettuce to crop. The pellets were never near the actual crop so all was safe for the humans at least.
My point to rosemummy was that the snails will be largely unaffected by nematodes and by removing the competition from slugs the snail population may increase. I have experienced this myself. I understand fully that many people do not like using pellets even the so called organic ones. I use all methods: Nematodes, Copper tape, physical barriers, coffee grounds & hand removal- pellets are my last resort.