Sowing old seed

[Uli]

Dear All,

Here is a picture I would like to share with you. It shows sprouting seed of three Dahlia species and one hybrid. Not very exciting you might think but the seed was very old, stored in paper envelopes in a domestic refrigerator (not freezer) at typical fridge temperature.
The seed of Dahlia tenuicaulis in the bottom right pot dates from a trip to Mexico in 2006, the seed in the other 3 pots was picked in 2011 in my former garden. I am particularly pleased about this germination because I had lost all three Dahlias after my move to Portugal. With better knowledge of this climate I will give them another try. The blue granules are slug pellets, I do not want that to happen.......

[Martin Bohnet]

I can confirm that Uli treats his seeds excellent - last year he gave me Tigridia seeds from (i think) the very same trip, and they were sprouting fine. did not count them before, but above 90% seems a safe bet.

but I do have a question about the slug pellets: are those methaldehyd or iron(III)-phosphate pellets? whenever I tried to protect seed from slugs using the phosphate-based ones, they molded within days - which likely wasn't helpful for the seedlings either.

[Uli]

I use Methaldehyd to be sure. These pellets will also become mouldy after some time and in fragile and valuable seed I replace them with fresh ones.
My seed trays and pots are covered with wire mesh to exclude birds so this protects against accidental intoxication at the same time.

[David Pilling]

From a hedgehog web site (talking about 2022)

"Good News! Metaldehyde Slug pellets can no longer be sold or used in the UK, as of Friday 1st April, because they mainly contain a pesticide called Metaldehyde which poses an unacceptable risk to birds, dogs, and wildlife such as hedgehogs.

We know slugs munching on your prize-winning lettuces can be irritating but slugs and snails play a hugely important role in maintaining a healthy ecosystem! In March 2022 the RHS announces that they will no longer be classing slugs and snails as pests saying "The RHS is all too aware of the role that gardens have in supporting biodiversity and as such will no longer label any garden wildlife as pests".

[CG100]

"Good News! Metaldehyde Slug pellets can no longer be sold or used in the UK, as of Friday 1st April, because they mainly contain a pesticide called Metaldehyde which poses an unacceptable risk to birds, dogs, and wildlife such as hedgehogs.

I believe that the ban is only for domestic/householder use - agricultural use remains legal?

Most? All? Slug pellets are cereal based, which is the attractant/food, the same as with rodent baits. The toxins are added at just a very few %. Hence they all mould pretty quickly if damp enough.

[David Pilling]

I believe that the ban is only for domestic/householder use - agricultural use remains legal?

I am no expert, indications from Google, pronouncements of UK Government are that the ban applies to farms too.

Interesting comment on why slug pellets go mouldy.

Always been interested that:

"Metaldehyde was originally developed as a solid fuel. It is still used as a camping fuel, also for military purposes, or solid fuel in lamps. It may be purchased in a tablet form to be used in small stoves, and for preheating of Primus type stoves."

[CG100]

Amazingly, perhaps, slugs are a very serious agricultural pest even today - at their worst they can occur at rates of hundreds, possibly thousands, per square metre in preferred soil, which would include plenty of arable land (numbers will be online somewhere).

Most baits for any species are produced using machinery designed for use in the food or feed industry - either livestock pellet/pencil making for pelleted poisons, or pasta-making machines (lots of rodent poisons are available in blue pasta shapes). The only exception that I can think of are wax blocks used for rodents, and even they are laced with cereal as well as poison. (I am unsure that tracking powder is used/legal now - I haven't seen it for sale for years.)

I know that metaldehyde was still permitted because there wasn't any realistic alternative for commercial growers - aluminium was, if not now, discounted.

I had completely forgotten the waxy metaldehyde fuel blocks!! 

[Martin Bohnet]

Methaldehyd is legal in Germany - I guess it's EU-wide. Wasn't Brexit made to escape all those pesky EU rules?

[CG100]

Campaigns to get it banned in the UK have been going on for a very long time, since way before Brexit. Perhaps the EU has escaped a new regulation pushed through by the UK?

There would, I strongly suspect, be more people in the UK thankful to have escaped it still being legal, than the other way around.

Metaldehyde is toxic, it can kill non-target wildlife, but is there any real evidence that it does and at a significant level? Doubtful.

[Martin Bohnet]

Don't get me wrong, I don't use it - though i'm convinced the most "toxic" substance for hedgehogs is rubber. Lost one in our street last summer.

On the other hand I wonder if one can reach toxic phosphate levels with slug pellets. too much phosphate seems to block calcium uptake, as a quick google search turned out. too much Iron can catalyze hydroxyl radicals. So much to the theory, but does it happen? Solubility in water and thus mobility is low. still I'd guess it does more damage in pots than in the open garden.

[janemcgary]

I use the iron phosphate slug pellets, but instead of putting them in the pots, I put little piles of them between the pots (which are plunged almost to their rims), since the slugs are likely to hide out under the pot rims and crawl around at night between the pots. This seems to have been very effective on slugs, but it doesn't get rid of cutworms. There are enhanced products containing (can't remember the exact word -- spinosab?) which are supposed to be better, but they don't get the cutworms either. Only late-night visits with a strong headlamp work.

[CG100]

Biological controls (mostly? all? are nematodes) for soil pests work very well in pots, so long as there is no major rate of  reinfestation, which is pretty much the case for things like cut-worms as they are laid as eggs very seasonally.

I stll have metaldehyde pellets and would continue to buy them as I only ever use them in the greenhouse (or very occasionally indoors, when a silver trail gives away intruders that I can't find.

If anyone has ever seen a slug or snail starting on a pellet, the poison must work extremely quickly as the molluscs are writhing PDQ after a small taste.

[David Pilling]

There should be something to water on plants that makes them unpalatable to creepy critters - garlic water or summink.

[CG100]

(can't remember the exact word -- spinosab?)

Possibly one of the carbamates? The common one was/is methiocarb. Possibly also banned in the UK/EU?

Spinosad is a thing - a natural, reasonably environmentally-neutral compound outside of its use as an insecticide. I can't find mention of its use as a mulluscicide. It can be extremely persistant (half life of 100's days) in the environment unless exposed to water and strong sunlight simultaneously.

[Wylie]

I have found that most snails and slugs are clever enough to use pellets as some sort of obstacle course. I will go out at night before going to bed with a salt shaker and it seems to deter others.