Killing the grass

Now I need to suppress the grass in the "moss zone". There is too much grass to pull it out, so, even though I don't like using chemical poisons, I'll have to spray some herbicide.

Rumor is that RoundUp does not damage the moss, just the grass. On one of the internet gardening forums (don't remember, maybe GardenWeb) somebody mentioned that diluted ready-to-use RoundUp had some negative effect on moss, while concentrated RoundUp killed the grass without damaging moss.

Quick trip to Home Depot confirmed that the ingredients are slightly different in the ready-to-use and concentrated versions.

Concentrated:

• Glyphosate, isopropylamin salt - 18%
• Diquat dibromide - 0.73%
• Other ingredients - 81.27%

Ready-to-use:

• Glyphosate, isopropylamin salt - 2%
• Pelargonic acid and related fatty acids - 2%
• Other ingredients - 96%

The second line is different, plus nobody knows what hides behind "Other ingredients".

Anyway, I decided to go with the concentrate:

I sprayed it out in prescribed concentration.

My only concern is that even though it is sunny now, the ground is very wet (which is always the case in winter in Seattle!). I am afraid that the grass is not "thirsty" enough and it will not be eager to suck the poison in from the leaves. We will see. Even though the label says "results in 12 hours", I don't believe I'll see real results in less than a week or two - as I understand, the poison blocks the ability of the grass to "eat", so it should take some time for it to "starve".