Do the new ferrous phosphate organic slug pellets work as well as the old metaldehyde slug pellets? This question was posed by a reader who felt the new slug pellets were ineffective.
Slugs infesting a vegetable garden. 3 on a lettuce!
Banning Metaldehyde Slug Pellets
The government moved to ban metaldehyde pellets that have been a gardener’s staple for as long as I have been alive. The ban was overturned on technical grounds but it remains a possibility.
There is supposed to be a danger that the poisoned slugs and snails would be eaten by wild life and poison the wild life in turn. Although the risk is there in theory there is little evidence for it in reality.
The main reason behind a ban was farmers using metaldehyde based slug pellets near water courses causing pollution problems. Remember, gardeners use a handful but farmers use hundreds of kilos.
Ferrous Phosphate Slug Pellets
The alternative slug pellet are thosed based on ferrous phosphate. Ferrous phosphate pellets are organically approved and, in the UK & EU, further treated with a bittering agent to dissuade pets from eating them.
There’s no evidence of risk to wild animals or pets from pellets or corpses except for some vet reports in the USA about dogs eating large quantities of pellets falling ill.
Eventually uneaten pellets degrade and become nutrients for the plants. Incidentally, I think they last longer in showery weather than the metaldehyde pellets.
Different Actions
When a slug or snail eats a metaldehyde pellet they produce a lot of slime which they leave behind them as they slither off and die. It’s very easy to see how many have been killed.
With ferrous phosphate slug pellets the action is different. The slug loses the desire to eat and goes off to wherever it hides in the day and dies out of sight. It’s not at all obvious to the gardener that they’ve been effective.
The Slug Pellets Disappear
If you scatter them as directed, i.e. thinly, and they’ve vanished over a night or two it means they’ve been eaten by the slugs & snails. Re-apply and you’ll get their surviving pals. The pellets actually attract the slugs so don’t over-apply as it can be counter-productive.
Summing Up
To sum up; I think ferrous phosphate slug pellets are probably slightly more effective than metaldehyde slug pellets. They are also arguably safer and definitely greener. On the negative side, they are slightly more expensive but there’s not a lot in it.
More Information on Organic Slug Pellets
I resorted to these in raised beds with netting on as hundreds of slugs were getting in. I grew my brassicas from seed and to see them being decimated angered me, so reluctantly after trying sheep wool collars and beer traps,my husband brought these home. I used them and find they do work.
I sprinkled them amongst the cabbage, broccoli, cauliflowers and beetroot. I have also put them around mt courgettes after the sheep fleece failed. I have harvested my first 5 heads of broccoli and beetroot which was eaten by micelast year!
However I planted spinach between 2 rows of carrots and the slugs crawled up the foliage of carrots and over onto the spinach.As they came over my raised beds and straight onto the wet leaves of the carrots they didnt come into contact with the pellets so thats why they failed. Otherwise I have used them in my pots of zinnias and in amongst the hostas in case the copper tape evades any as last year they looked like lace leaf plants! This year with sheep fleece, copper tape and pellets, we’re doing beautifully well!