I spray round-up on moss to kill weeds and it don't kill the moss and other people here have said the same. One "GW"
poster said here that she just got done with a class on growning moss. She said spray the weeds with round-up because it will not killed the moss.

Be very careful. I used roundup and it did kill the existing moss. The good news was that the moss came back and eventually recovered but the weeds did not. I would try some on a patch before general spraying.
On the other hand there is good evidence that the moss will prevail by itself (see other postings) and force out the grass. I must admit I don't worry about grass anymore even though my area was once lawn. You might try mowing low and often - hard on the grass but not at all on the moss.
Good luck,
Alan

Rounp up works by killing the roots. Moss don't have real roots. What kind of round up were you useing that killed the most. If it came back fast, maybe you did not kill the moss.It just looked like it was dead. I have not been growing moss long but have sprayed round up on the weeds in the moss a lot without killing the moss. Yesterday I sprayed 10 gallons on weeds in a new moss area. The moss in that area was brown before spraying. I will see how that area turns out. In the other area where I had green moss before spraying the moss looks great with very nice green lust look. Maybe it is not the round up that killed your moss. Maybe the weeds were giving shade to the moss and when the weeds died the moss had too much sun. I been spraying my moss with WATER a lot since the roundup.

I have moss coming through the cracks of the stone on my patio, love it very pretty but also lots of grass and weeds, I want to get rid of the grass and weeds but not the moss? What do I do , I also have a brick wall I would like to cover in moss how do I do this?

If grass is more the problem than broadleaf weeds, look for a product by Ortho called Grass-B-Gon. It kills grass only and doesn't kill broadleaf plants. It works great around the base of flowers and shrubs. I don't have a bottle in front of me, so read the label to see what it says about moss, which isn't technically a broadleaf plant or a grass. It only comes in a small spray bottle, though, not a concentrate.

Hi

Don't suppose it would work on selaginellas ,baby tears ?? Don't have trouble with grass as it's in deep shade but a type of trandescatia not the fancy but the weedy kind lol gary

http://www.weedbustersbiocontrol.com/

I know this is an old thread, but it's timely for me, as the dandelions are overtaking my patio this Spring. I tried David Plante's solution, and I'm surprised how well it works! 24 hours after spraying, the dandelions in the cracks are dead, the grass is dying, and the moss (which I tried to avoid soaking) seems largely unaffected.

FYI, I misread the directions and used 1 cup of Espom salts in 1 gallon of distilled vinegar, and it still worked great.

A local landscaping company told me that the trick to killing weeds is mixing in a dash of MiracleGro into Roundup Quik Pro (it's in a blue bottle). He said the MiracleGro causes the roots to open up and take in the Roundup.

mow it as low as you can with mower, then take you gas trimmer and just barely trim the top of the moss while getting weeds and grass,it is tough because it is so easy to accidentally dig into the moss, I also think that by trimming just the top of the moss it helps spread it. I tried the weed killer one time on about a fifty foot patch of moss and it killed the moss by about 80%

I have found the best way is to place flattened cardboard on the area which will suffocate the grass and weeds but spare the moss which thrives in the moist shade. Leave it on about a month but check periodically. Hold the cardboard in place with weed fabric pins. The area needs to be watered before putting doown the cardboard. This really works!

if possible, DO NOT purchase round up or any weedkillers !! Firstly, I had a tree removal company dump all their woodchips on the lawn. indeed, kill the grass by blocking off the sunlight . . mulching . . i’ve been digging up the roots, basically I’m down to small but numerous clumps. Grass is much easier to harvest in late fall and warm winter days. particularly after a rain !!! i’ve used straight up vinegar, particulatly for those spots where I know the grass roots are firmly estabished underneath healthy patches of moss. Though the moss in those areas seemed to dry up, it will revive. moss is boss. search mountainMoss . . look for mossin’ annie. she has a very informative book!! don’t give up !! moss needs nice sprinkles of water throughout the summer months but not nearly as much as grass !!

I used a sheet of black plastic from home depot. comes in a roll and not very expensive. Cover the area where you have the weed problem and pin it down around the edges. Moss seem to tolerate a lack of sun much better than weeds. I checked it each day to ensure there was not too much stress on the moss. After about 5 days the weeds were all dead and while the moss was not happy it did come back quickly.

I try to pull weeds manually but I use this technique when they get out of control.