Sulphate of Iron (6 table spoons in a 1.5 gallon watering can) would definitely work. But would stain the gravel rust-colour. Might not necessarily be bad; test first.
Try spraying bleach. Thin bleach is best, the viscosity of the thick bleach interferes with the spraying.
Also try vinegar (5% acetic acid, the cheapest you can get).
Moss spores (not seeds) would be quickly replaced by that blowing around all the time.
Use chemicals carefully.
location: Surrey Hills, England, ex-woodland acidic sand. "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
As I said we have been spraying with various moss killing stuff for a long time, including the stuff advised above. One big problem for us is that the drive is cambered in such a way that any liquid put on it runs into the beds alongside. That makes it harder to use chemicals which might kill the shrubs etc. in those borders. Also we have 3 cats and if you read the info on most of the moss stuff, it says keep pets off for 8 hours after application. Try it! Not sure either that our regular dog walking visors would like their animules to be poisoned either.
It is difficult. I am not being awkward, we have tried.
Corollary question. How long does it take for new porous tarmac to become covered in moss?
Dunno @Palustris and I share your concerns about wekiller and pets. We may wellend up just letting the weeds grow and then mow them but under the gravel are the stones laid or left by the previous farmer owners so mowing not be good for the blades.
At least as we hoe and rake the gravel gets thinner. I'd much rather have a stone drive, even if it is lumpy and bumpy and I've noticed that some very shy goldfincheslike some of the weed seedheads in the mix so maybe we'll just leave it.
Vendée - 20kms from Atlantic coast.
"The price good men (and women) pay for indifference to public affairs is to be ruled by evil men (and women)."
@Palustris, Last year I tried a few handfuls of lawn sand on our mossy tarmaced drive. I noticed the moss did turn black and die but has now come back. No sure how toxic it is though, or what's in it?
Did your drive look any better during the drought?
@Palustris, Last year I tried a few handfuls of lawn sand on our mossy tarmaced drive. I noticed the moss did turn black and die but has now come back. No sure how toxic it is though, or what's in it?
Lawn sand is FeSO4 (ferrous sulphate, sulphate of iron) it is mixed with sand to make it easier to spread uniformly. On lawns it will blacken the grass also. Much better is to buy iron suulphate, dissolve it in water and use a watering can. Recipe given elsewhere.
Iron sulphate is rated as "organic", tap water is not.
Did your application discololour the tarmac? But on black it probably wouldn't show.
re Palustris's question. Tarmac contains a lot of creosote-type materials so I guess it remainstoxic to evrything for quite a long time. Will stop the honey fungus creeping under the path!
location: Surrey Hills, England, ex-woodland acidic sand. "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
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Try spraying bleach. Thin bleach is best, the viscosity of the thick bleach interferes with the spraying.
Also try vinegar (5% acetic acid, the cheapest you can get).
Moss spores (not seeds) would be quickly replaced by that blowing around all the time.
Use chemicals carefully.
"Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
At least as we hoe and rake the gravel gets thinner. I'd much rather have a stone drive, even if it is lumpy and bumpy and I've noticed that some very shy goldfincheslike some of the weed seedheads in the mix so maybe we'll just leave it.
I noticed the moss did turn black and die but has now come back. No sure how toxic it is though, or what's in it?
Did your drive look any better during the drought?
Iron sulphate is rated as "organic", tap water is not.
Did your application discololour the tarmac? But on black it probably wouldn't show.
re Palustris's question. Tarmac contains a lot of creosote-type materials so I guess it remainstoxic to evrything for quite a long time. Will stop the honey fungus creeping under the path!
"Have nothing in your garden that you don't know to be useful, or believe to be beautiful."