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I have never owned a garden before in my life (and as such, am only now learning that lawns need maintenance), but: I bought a house about 18 months ago that has a lawn roughly about a third of an acre (1.3km sq), and almost all of it is lawn grass:enter image description here

Last summer here (in the UK) was absolutely brutal - it didn't rain at all for around 2 months, and temperatures were regularly in the 30s (Celsius), reaching a record-breaking 40c. In that time, pretty much the entire lawn died. I tried watering & fertilising it at the time, but practically the whole lot went yellow in spite of this.

It slowly came back, and by winter most of it was green again; however it is now absolutely strewn with moss and some kind of weedy leaves:

enter image description here

A couple of weeks ago I scarified it with a towed scarifier for my ride-on, going both vertically and diagonally, then raked it all up by hand, but there was still plenty left. So last weekend I doused the lawn in iron sulphate using a backpack sprayer, about 900g to 20l of water. The patches of moss then went black (but the weeds were untouched), and so I scarified again today, which dragged up a lot more moss. I then attempted to go over it manually with a rake again to collect it all up, but even still there are big patches where the moss is inextricably entwined with blades of grass. And nothing seems to be touching these weeds, which are very flat, lower than the level of the grass.

I was going to reseed after today, but at this point I'm not sure. Should I continue to rake/scarify to attempt to get every inch of moss? Or is what I've done so far good enough to get it restarted? And should I just use a standard weedkiller on the patches of leaves (some of the patches are VERY large), or try to pull them by hand?

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  • What kind of grass is in the lawn now? What kind are you thinking about seeding? Mar 4, 2023 at 21:08
  • What type of soil is it? Mar 4, 2023 at 21:09
  • How high do you mow the lawn? Do you have access to a broadleaf herbicide? And how much shade does the lawn get (I see a large tree in your photo...)?
    – Jurp
    Mar 4, 2023 at 21:53
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    Before you go (further) utterly bonkers, ask yourself how much you personally really care about it being a pristine monoculture of "lawn grass" whatever species that may actually be, or if short green stuff you can mow is really just fine with you (as it seems to have been for 9-12 months, I'd guess.) This is not a subject where submitting to peer pressure from the monoculture cult is a good idea unless you've drunk too much of their Kool-Aid® and become one of them.
    – Ecnerwal
    Mar 4, 2023 at 22:25
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    1 km is 1000 m. 1 km^2 is a space one km on this side and one on that side. 1km^2 is 1 million square meters NOT 1000 m^2.
    – Boba Fit
    Mar 6, 2023 at 18:36

3 Answers 3

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I think the leaves you show may be daisy leaves, but time will tell - some people like a few daisies in the lawn, but the clumps do tend to spread. You will need to use a separate lawn weedkiller - avoid the combined lawn products such as weed and feed, they're fairly ineffective on weeds. In the UK, weedkillers and lawn fertilisers may be applied between April and September, although in September, an autumn formulation will need to be used. It's usual to apply these treatments in April in a granular form, then reapply 6-8 weeks later, and that's it for the year, unless you use an autumn formulation later on. Therefore, it's not the time of year to treat for weeds now, you need to wait till April when the weeds and grass are actively growing and temperatures are higher. The product I'd recommend is Weedol Lawn Weedkiller concentrate, previously known as Verdone - it can be applied with a sprayer or a watering can and should be applied to the whole lawn, not just the weedy areas - follow the dilution and general instructions on the container. Once that has dried off, it would be wise to use a lawn feed, one without weedkiller. You can get liquid lawn feeds or granular types; these latter are broadcast across the lawn evenly and feed the lawn for up to six weeks. Some granular types will contain mosskiller, but as you've treated for moss already, it may be better to stick to a product containing only fertiliser UNLESS you can see there is still quite lot of moss, in which case a combined granular mosskiller and fertiliser will be useful, but just make sure you don't mistakenly buy a product with weedkiller in it too. Don't keep trying to rake up or scarify any moss currently left, it sounds as if you've scarified pretty well already.

In respect of moss, unfortunately, after a hot summer accompanied by drought, you can expect a lot more moss than usual to grow during the following winter/spring; note that most of the grass will regrow, there is no need to water it while its in drought, particularly if water supplies are low anyway, which they usually are during a drought. Yes, the lawn will look terrible, might even be crunchy to walk on because the tops of the blades have died back, but it will recover, although yes, more maintenance will be necessary in respect of moss and weeds as a consequence.

As for any reseeding, it's a little too cold for that right now, especially if you are in a colder region of the UK, and may not be entirely necessary anyway. Note that seed should not be sown within 6-8 weeks of any chemical treatment being applied to the area; any product you use on the lawn should tell you when it's safe to do any reseeding necessary, as well as when its safe to allow animals and children to use the lawn following treatment.

Another hint - never apply fertiliser to a lawn when there's drought; the grass won't be actively growing and cannot take up the fertiliser, and it may cause damage if its a granular formulation and is left sitting on top of the lawn with no rain to wash it in.

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  • Thanks for all of this - you covered a lot of information I had no idea about 🙏🏻 I'll hold back and the reseeding and any further scarifying, and will look at applying a liquid weed killer for later next month.
    – indextwo
    Mar 6, 2023 at 10:51
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It is not carved in stone that domestic lawns have to be weed and moss free. In fact your life will be a lot, lot easier if you stop seeing "weeds" (aka wild flowers) and moss as a problem. It's different if you're a professional groundsperson. Then players will demand a smooth grass surface so they can play their sport properly. I live just north of London and last year in that record heat our local playing field was parched dry for weeks on end. But the grass soon came back after a spot of rain. So, in a nutshell, my advice is to ignore weeds and moss; cut the lawn regularly but no lower than 25mm; don't water - ever. You might also want to consider maintaining part of your lawn as a wildflower meadow (you can then plant attractive groups of spring bulbs), maybe crossed with meandering mown paths.

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  • My concern is that there are large patches, one of them about 20m², that is almost entirely moss - it looks like the grass is struggling to grow at all as there's very little visible.
    – indextwo
    Mar 6, 2023 at 10:29
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In the US, recommended grass height after mowing is 3" (75mm); it might be 2,5in (~65mm) for Southern lawns. Moss is rarely if ever a problem because it simply cannot out-compete the taller grass. This also helps control weeds because the seeds in the lawn do not get enough light to sprout at the grass's crowns. I understand that this height is way out of line for the UK, but have no idea why-tradition, maybe?

Moss can also indicate compacted soil: have you aerated the lawn? (usually, this is done in the autumn so that the winter frost/freeze cycle can help break up the cores).

Moss can also indicate a shady site, so is the grass variety on your lawn appropriate for shade? For example, in the northern US, lawns usually consist of Kentucky Bluegrass (a cold-season grass for full sun), but lawns with some to lots of shade use a miss of Bluegrass, Fescue and Ryegrass; these latter grasses are shade tolerant and will produce a nice lawn when Bluegrass can't.

The grass in your photo is not Bluegrass but could be a Fescue and may be a Ryegrass, but I'd guess it's a warm-season grass of some type. Given the presence of a very large tree, when you reseed in that tree's shadow you should definitely use a variety of grass appropriate for at least half day of shade. This will allow it to out-compete the moss better than what's there now.

So:

  • Mow higher
  • Aerate every autumn for at least the next few years
  • Use appropriate fertilizer per schedule
  • If such things exist in the UK, use a mulching mower and do not bag the cuttings.
  • Seed with a grass variety that is appropriate for growing in fairly heavy dappled shade, at least in the area in the shadow of the trees on your site.
  • Spot-treat or better yet, manually remove the weeds you don't like. Spraying an entire lawn is bad for birds, hedgehogs, pets, children and you. If you only ever manually remove weeds, you are very likely to become "friends" with some of them (clover, violets, some daisies) because it's such a pain to manually remove them. This helps both you, your family and tne environment.
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  • I don't know about the original lawn seed - all I know is the original owner redug the entire lawn and seeded it a few years ago. My ride-on has a mulching arm that basically blocks off the chute (rather than bagging) and I do that when the grass is dry - not very frequent in the UK! - otherwise it all tends to get clogged.
    – indextwo
    Mar 6, 2023 at 18:12
  • If you bag it, compost it (or use it for mulch on flower/veg beds) and if you compost it, return the compost to the lawn, or flower/veg beds.
    – Ecnerwal
    Mar 7, 2023 at 16:55

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