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Can I apply a moss killer and overseed my lawn

I’m planning top dressing and over seeding my well established lawn. It’s cut with a cylinder mower relatively short during the year. I’d like to apply a moss killer too but not sure what the knock on effects will have on the new seed. Advice required 


  • glasgowdanglasgowdan Posts: 632
    edited September 2019
    Don't use moss treatments when new seed is a factor. 

    Why exactly do you want to topdress it? Will you be aerating it at the same time? 
  • AuntyRachAuntyRach Posts: 5,100
    My understanding is that you should ideally use a moss/weed killer and then rake/scarily up after a few weeks and then you can overseed. Autumn is a good time to kill moss or sew seed but the weather needs to still be warm enough for seed to germinate so you might be tight on time to do both. I’m no expert, but this is what I do. (FYI the lawn will look rubbish as moss dies and after raking out, but worth it). 
    My garden and I live in South Wales. 
  • Killing moss after a scarify is often more effective. However, if there's a LOT of moss to remove and therefore a lot of fresh seed needed, just scarify it, seed, get it growing back then do a bit of moss control over winter.

    Seed will take really well if sown just now. 
  • It’s proper greens grass that is laid but the last 2 seasons I’ve had annual meadow grass creeping in. I’ve done a bit of verticutting over the season and I’m hopeful that the Topdressing overseeding will combat part of the problem. The moss issue is side issue which isn’t priority but if I could apply something without it having effect on the seed I would. I’m regular with the spring/ summer feeds and autumn feed. Has anyone tried these new moss products - no rake? Not sure that they’re actually a moss killer- but rather organisms that eat away at the moss?
  • glasgowdanglasgowdan Posts: 632
    edited September 2019
    Mo Bacter products only work well in very specific weather conditions so it's hard to get it right. They don't do anything about thatch. 
  • ObelixxObelixx Posts: 29,636
    I wouldn't bother re-sowing without first fixing the problems that allow the moss to grow so the first thing to do is to scarify, either by hand or using a machine.  You can buy or hire machines about teh size of a sall electric mower and they will do a much better job than hand raking.   

    Then you need to improve drainage by spiking the fork at frequent intervals witha  garden fork pushed in as far as you can and wiggled to open up tthe holes.  brush in dry, sharp sand (not builders') to keep those holes open and aerate the grass roots.

    Then rake over the bare patches to loosen the soil, sow new seed and tamp it down with the back of the rake.  Water witha  sprinkler if you don't get rain.  Do this all in the next week or so as this is ideal grass sowing time.   April is the next good sowing time.

    Vendée - 20kms from Atlantic coast.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • Thanks for all the advice.
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