Forum home Problem solving

Weedkiller to use before new lawn?



Hi all 

I am in the process of trying to revamp the garden for the summer. I am going to start digging out the old lawn. I laid it a few years ago but didnt even the soil or use top soil so a little rushed and needs improving so the kids can get out there without turning their ankles.

My question is before I put the top soil down what is the best weed killer to use and which ones should I avoid? The area is around 25m2.

Thanks for any help!! 



  • Busy Bee2Busy Bee2 Posts: 1,005

    You need a glyphosate one to kill the roots of perennial weeds.  You need to apply it all over and wait for a couple of weeks (check pack) to make sure the chemical has got all the way down to kill the roots.  When you have waited the allotted time, dig out the old brown turf/weed mixture, level carefully before re-seeding or turfing.  Glyphosate neutralises on contact with the soil, so will not affect the new seeds or turf.  It sometimes has brand names at the GC, so look at the small print or ask an assistant.

  • Busy Bee2Busy Bee2 Posts: 1,005

    Don't do it on a windy day, as the wind may carry droplets onto other plants in your borders, and it is much cheaper to buy it concentrated and mix with water (as per instructions) in the watering can, than to buy a sprayer (which would take ages anyway).  Or when it might rain - the chemical needs time to dry on the leaves and penetrate the plant.  Are you absolutely sure that the roots of the current weeds are so deep that you couldn't just dig them out?  I am going to put some on parts of my paddock that I'm digging out, because the docks and nettle systems are so ingrained, but dandelions don't go so deep.  I only use weed killer as a last resort, but there are times when we all need a little help to ensure the problems don't come back.

  • Thanks for replies. I was going to use weed killer because I thought I had too? There may only be a few weeds that cant be dug out. I wasn't aware the wait was so long (2 weeks) before I could lay turf. Should I only be using weed killer on the bigger weeds and not across the whole garden?

  • DovefromaboveDovefromabove Posts: 83,787

    If it was me (and I'm well aware I'm not you and I only know part of the story here) I'd have a go at renovating that lawn.  I've dealt with far worse and got -a decent play-lawn out of it. 

    My guess is that when you turfed it you used the lawn far too soon so it became uneven - you have to keep off freshly laid turf for quite a while, and after than, only gentle walking, not heavy duty play!  It has also not been mowed regularly enough.  Lawns need mowing at least once a week, sometimes more, right through the growing season.

    I would kill off or dig out the bigger weeds (I've zoomed in - there aren't that many) and mow the lawn with a rotary mower set on high.  Treat with an all in one Weed & Feed and keep mowing - the grass will begin to grow outwards rather than upwards - then you can fill in any hollows with topsoil and seed over them - you'll soon have a lovely green lawn.  It will never be a bowling green, but you have children - you don't want a bowling green.  Soon you will be able to lower the mower blade, but never cut it very low - it will scalp the grass and weaken it.  Little and often is the way to get a good lawn.

    Even if you take all that grass up and turf it now, your new lawn will not be able to withstand children playing on it 24/7 (or even 12/7) for the first season.  

    If you do what I suggest they can play on the lawn all this summer - just ask them to be careful of the re-seeded bits - they can even have little watering cans and water them for you when the sun is shining. image

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • Yes you might be right! Some of the "holes" are very big tho and not an awful lot are flat. There are maybe more weeds than the picture shows as its pretty bad out there. I did want to make it flatter. The back area we wanted to chip bark (were play house and slide are) and have a nicer lawn nearer the patio. Its hard to see from that pic how bumpy it is. We also wanted a border around the lawn using the stones you can see at the back. Not sure if this pic shows you more? 


  • image


  • image


  • Busy Bee2Busy Bee2 Posts: 1,005

    I would be inclined to agree with Dove, unless like us, you have a stone problem.  All our soil is infested with lumps of limestone/sandstone about the size of fists.  If, as you say, you didn't really spend long preparing the soil before laying the first lawn and you didn't dig down some way and sift it a bit, and you have stones, you will be better to start again, otherwise, as with our 'pitch' they will rise to the surface and affect the evenness of the lawn, or the soil will sink around them, and it will never be 'right'.  No paddling pools!  Nothing guaranteed to turn your lawn into slimey muddy dead grass muck than a paddling pool. 

  • DovefromaboveDovefromabove Posts: 83,787

    For a play lawn I would patch, fill the holes, re seed the patches etc.  We had three large skips standing on our front lawn for an entire summer - you cannot imagine how it looked when they were removed, large ant hills, tall weeds all around the bases of the skips and three bare patches each about 8' x 6' - we took out the weeds by digging around the roots with a sharp kitchen knife, mowed and mowed and mowed, raked the bare patches, levelled with some topsoil and scattered some lawn seed and waited.  We now have a perfectly respectable front lawn.  (A few dandelions again, but I'll get to grips with them soon.)  April or September are the perfect time to do this. 

    We had thought about getting it re-turfed - that would've cost hundreds of pounds - what I did cost about £25.

    But first you need to get out there, raise the bar on the mower and mow it - now - don't want to nag, but the main problem with your lawn is that it's not ever been mowed regularly - those weeds wouldn't be as big as they are if you'd mowed it regularly last year ................. I'll get my coat image

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • Yes stones were an issue but didnt take the time getting them out. This time I would dig and weed a lot better and use top soil as been told our soil isnt "good". This was why I asked which weed killer to use over the whole area before using top soil. Or now if I should only use weed killer in the area of weeds. We never fed the last lawn either so will need to look after it alot better than last time. I hope to get advise of feeding etc once im at that stage.

    I have also been looking online and there are so many places to buy turf, do I just pick one as no one i know has used any 

Sign In or Register to comment.