Bio washing liquid for moss?

I am looking to use Lidl Formil Bio to kill moss on driveway. I previously used Aldi bio powder very successfully by sprinkling powder on the moss. However, because the spreading was not evenly done there were small patches of moss remaining. I then thought it would be better to spray a liquid bio mix to get a more even kill. I don't know the concentration that would be required so I propose to use the strongest concentration by the following method. I will measure pure water into the knapsack sprayer and spray the drive way with the water. I will then measure the remaining water to calculate how much water was used to wet the drive way. e.g. start with 10 l of water and find I have 4 litres remaining, meaning I have used 6l to wet the drive way. I will then use 5l of water and add the 980 mls of formil bio to give me the c. 6l to completely wet the drive way with the bio solution. I will report back the effect when we get a few dry days.

What would you say is a good starting point?

The washing detergent is cheap enough so I'm going to give it a proper go with the knapsack sprayer. I've previously sprinkled it by hand but like others here have said you inevitably end up with spotty over/underdosing.

You can also use sodium hypochlorite (i.e. bleach) to kill moss. Not sure if the overall cost is more or less than detergent.

Where do you buy milling salt?

Power hose

Get a better power washer. 🙂

Well, I can't say that the bio detergent treatment achieved much in terms of getting rid of the moss. I used up a whole box of the Lidl stuff by desolving 500g of powder in a jug of hot water, then diluting that in a 5l sprayer and soaking the moss. Not sure how much is in a box (5kg?) so probably sprayed out about 50 litre or so of the mix and moss is as healthy as ever. The rest of the place is pretty clean and fresh though I might add.

Did it rain on it within a couple of days? Sounds like it was too weak or washed away. I did mine recently and got good results.

Hot water to start with and then I filter it through an old t-shirt in to the sprayer.

In any Agri store.

I get mine in Coop Superstore, ~6 euro for a 25kg bag, that covers a good area.

I put it on in dry weather and let it sit there for a few days before rain, it works well, Ive most of the moss removed from the drive.

Well my tarmac is old and worn but I haven't noticed any damage from the salt, it looks alot better than it did with the moss on it.