2020 Lawn thread

[Dr Mike Oxgreen]

r44flyer said:

Tenacity, after about a week working on the crabgrass on my in-laws lawn... (and one of the severe topdressing and overseeding on the bigger lawn, which is just sprouting).

I’m interested in this, because I’ve read that it can also have a significant effect on Poa annua, even though they only claim that it suppresses it.

When did you use it?

I can’t quite work out whether or not its pre-emergent function is also selective; i.e. will it also prevent germination of desired grass seed, or does it only suppress germination of crab grass and Poa? If it doesn’t affect germination of ‘good’ grasses then it seems ideal to apply it a fortnight or so before doing the autumn routine of scarifying (getting rid of the killed grass) and overseeding.

[Semmelweiss]

7 days after Tenacity applied



29 days after Tenacity applied



I did water it every day until 10 days ago, for an hour a day.

Crabgrass is effectively gone, but will repeat the Tenacity application again first week in October.

[DonkeyApple]

Crumpet said:

DonkeyApple said:

Thanks. They only seem to have one ‘shade’ grass and it doesn’t exactly rush to shout about being ideal for shade.

I take it the one you used isn’t the same one in the link?

Also, how is the grass a few months on? I’ve always found that any old seed will look great when new but within a few months it can thin out and go whispy then kaput.

Ah, well, can’t answer that about longevity, I’m afraid. I suspect it will probably need a top dressing and reseed every spring but nothing too exciting. To be honest this is the first year I’ve taken an interest in keeping my lawn alive!

It was this one;

https://www.lawnsmith.co.uk/prod/lawn-grass-seed/s...

Thanks.

[dhutch]

DonkeyApple said:

Crumpet said:

DonkeyApple said:

Thanks. They only seem to have one ‘shade’ grass and it doesn’t exactly rush to shout about being ideal for shade.

I take it the one you used isn’t the same one in the link?

Also, how is the grass a few months on? I’ve always found that any old seed will look great when new but within a few months it can thin out and go whispy then kaput.

Ah, well, can’t answer that about longevity, I’m afraid. I suspect it will probably need a top dressing and reseed every spring but nothing too exciting. To be honest this is the first year I’ve taken an interest in keeping my lawn alive!

It was this one;

https://www.lawnsmith.co.uk/prod/lawn-grass-seed/s...

Thanks.

In addition, we are using their 'StayGreen' which is a drought and semi shade tolerant mix, because we are on sandy soil (actually 4-6inches of soil and then sandstone bedrock) far to early to see, but the initial areas I have seeded front scratch with it germinated well an have produced a good if still young lawn including in areas with very little direct sunlight.

Obviously nothing will grow without some sun, and unlike some sites, lawnsmith appears to have a very honest appraisal of the products they sell.

Daniel

[r44flyer]

From what I've read, Tenacity doesn't suppress the growth of desirable grasses, and it was advisable to apply at time of overseeding. However, more research is probably a good idea as a lot of the material obviously relates to US lawns and they often favour much different grass species to the UK.

I've sown a tray with the mix I use for overseeding to test if any of it dies, just in case. It is a pre- and post- emergent herbicide of course.

[epsilonvaz]

Anyone had a similar experience to me? I use the Scotts Evengreen drop spreader
https://www.amazon.co.uk/EverGreen-016057-Scotts-E...

Have got lawnsmith summer fert for clay.
https://www.lawnsmith.co.uk/prod/lawn-fertiliser-p...

My lawn is about 360sqm. I have got through about a quarter of the 330sqm pack and have covered my lawn, twice. I checked that the spreader was calibrated as per instructions. My only guess is that the fert may be a bit too large for the Scotts holes? Anyone had something similar? I am a bit apprehensive about going over it again because of the risk of scorching it.

[r44flyer]

You won't scorch the grass if you've only put a quarter of the fertiliser down. Can you not adjust the holes in the dropper to let some more through?

I have to say I quickly gave up on drop spreaders as I found them to be inaccurate and unreliable, and very prone to leaving lines in the lawn. A rotary spreader wins every time.

[epsilonvaz]

I think that's what I'll do. I'll cut a piece of foil to 1msq, then go over it with the spreader and weigh what comes out until I get the correct application rate.

[Cl4rkyPH]

epsilonvaz said:

Anyone had a similar experience to me? I use the Scotts Evengreen drop spreader
https://www.amazon.co.uk/EverGreen-016057-Scotts-E...

Have got lawnsmith summer fert for clay.
https://www.lawnsmith.co.uk/prod/lawn-fertiliser-p...

My lawn is about 360sqm. I have got through about a quarter of the 330sqm pack and have covered my lawn, twice. I checked that the spreader was calibrated as per instructions. My only guess is that the fert may be a bit too large for the Scotts holes? Anyone had something similar? I am a bit apprehensive about going over it again because of the risk of scorching it.

If you’ve only used a quarter of the pack but covered your whole lawn then you’ve put too little down per m2.

On this basis, doing another run on the same setting, and again if necessary should be OK, but only if the spreader continues dropping at the same rate as the first time you did it.

The way those drop spreaders work is one of the wheels spin the axle that feeds the fertiliser through the grate at the bottom. With the spreader empty, check the wheel is spinning the axle and is free of obstruction.

If it is spinning it, check that the wheel is spinning when you push it along. Sometimes the wheels can be stiff and not spin which means very little fertiliser will drop through the holes. You may need to use downward pressure on the spreader for the wheel to spin.

If you’ve checked all of the above, and the settings are definitely correct, try walking a bit slower?

[Semmelweiss]

epsilonvaz said:

Anyone had a similar experience to me? I use the Scotts Evengreen drop spreader
https://www.amazon.co.uk/EverGreen-016057-Scotts-E...

Have got lawnsmith summer fert for clay.
https://www.lawnsmith.co.uk/prod/lawn-fertiliser-p...

My lawn is about 360sqm. I have got through about a quarter of the 330sqm pack and have covered my lawn, twice. I checked that the spreader was calibrated as per instructions. My only guess is that the fert may be a bit too large for the Scotts holes? Anyone had something similar? I am a bit apprehensive about going over it again because of the risk of scorching it.

I have the same spreader and used setting "26" with my Spring & Summer (Sandy Soils). I walked normal walking pace, and it used 5kg bag for 200sq/m - one pass and the hopper was empty.

What setting have you used?

[epsilonvaz]

Thanks for the responses everyone.

I used setting 6.5 based on this:

[Semmelweiss]

Ah - that's a different spreader to mine - I have the rotary.

I had that one and it was cr4p. It never dropped the fertiliser with any accuracy and used to block up and when it did drop the product, it just dumps it directly below the spreader. I chucked it after 12 frustrating months and got the rotary as a replacement, problem solved. The rotary spreader distributes the fertiliser by "flinging" it out over a greater area.

[dhutch]

As per the above, scorching is based on the dose rate out down no the (almost random) number on the spreader, so it you have only put down a quarter of if you should be good to go.

My experience is trying to 'calibrate' these spreaders by doing a square as you suggest is a nightmare to get any sort of meaning full accuracy.

If you have put down 1/4 of the dose rate in a reasonably even application, I would be quite tempted to just do that another three times, at 90 and 45deg passes, which will at least all but remove any risk of stripes.

Or you could increase it a bit and see how that does, try and find a sweet spot where you can put it on in two passes, say.

Be aware that it will not be logical or linear, so if you double the number you wont get double the application rate, you might get five times and not realise you are giving 10x dose till three lengths in you have used half the mix! But given how low the first pass has been, worse case even if you put it on three times a thick, you have still hit the right dose.

I my experience a straight NPK fertiliser is much less risky to scorch than a 4in1 treatment as even the 'max dose' is well below dog-wee levels of nitrogen, Iron Sulphate also appear to take a higher than ideal dose fairly well, dont ask me how I know.... ...was aiming for 3/4 of the max, got sums wrong, ended up doing 6/4max dose. No issues.

I have also ditched the drop spreader for a rotary, faster and less stripes, but if you have one do 2-3 passes the drop also go it on fine.


Daniel

[taxboy]

Simple question regarding scarifying - after scarifying and overseeding does the lawn need top dressing with soil every time this is done or only if there are large bare patches

[Cl4rkyPH]

RichB said:

I have a similar issue and have assumed it was uneven application of the fertiliser back in late April. Perhaps not?

You were right! After fertilising (Lawnsmith Summer and Spring) with my drop spreader I’m horrified to see, despite the stripes dramatically improving, a clear path where I did (and didn’t) drop fertiliser again.

I’m now confident that drop spreaders are just pants for medium to large gardens and have just bought a used Scott’s rotary spreader off Facebay in perfect working order for a tenner.

Whilst I’m happy knowing what the problem was, I’m still annoyed that I’m going to have to live with these weird stripes/patches until I can fertilise again in several weeks.

[stevensdrs]

stevensdrs said:

Dr Mike Oxgreen said:

stevensdrs said:

dhutch said:

stevensdrs said:

This was a new small lawn replaced last year and it was all green until I put Aftercut on it. What the hell has happened?. Will these areas come back or will I have to seed them?

There are a range of products under the 'Aftercut' brand, do you know which you applied? Could the effect areas perhaps have too heavier a dose?

It was the all in one triple action stuff. I have used it before and never had this result. Usually you get some browning where it has killed the moss but this time there were no moss patches to speak of. I just used the same dosage I always use and my other lawn which I did at the same time didn't have this reaction. I wonder if having a few days sunshine may have caused burning even though I watered every night. It's disappointing as I had just about got it to a good standard and now it looks like I am back to square one with it.

It’s possible that you’ve got a fungal disease called “red thread” - that’s what it looks like. This is encouraged when the air is humid - which it has been for the last couple of weeks and will be especially bad in hot weather. The LawnSmith web site issued a red thread alert a few weeks ago. I recommend reading their page on red thread.

I also note you say you water “every night”. This is bad practice, for two reasons. Firstly, watering in the evening allows the grass leaves to stay damp overnight, which will encourage fungal infections like red thread. Instead, water in the morning. Secondly, it is far better to water less frequently but water very thoroughly when you do. This makes the water penetrate deeply into the soil, encouraging the deeper rooted grasses to send their roots downwards and makes them more drought resistant. By watering “little and often” you are only watering the top inch of soil, which will favour the shallow-rooted weed grasses and make your lawn vulnerable to drought.

So, I recommend:

1) Switch to morning waterings, no more than once a week and make it a really good soak.

2) Feed your lawn if you haven’t done so recently. This will speed up growth and cause any red thread affected foliage to grow out.

3) When mowing, collect the clippings if your mower can do that, rather than leaving clippings on the lawn. Normally I recommend leaving clippings from time to time, but if there’s the possibility you’ve got red thread you want to remove the infected material.

Edited to add:
I’m not a fan of “all-in-one” products. It looks to me like your lawn doesn’t have any moss, so why are you applying a product with moss killer in it? And it looks like you have very few (if any) weeds, so why are you applying a product with weed killer in it? You’d be far better off applying just a feed product - they’re way better and there’s hardly any risk of scorching. If you get the odd weed, spot-treat them with a spray bottle of Verdone or similar.

Edited by Dr Mike Oxgreen on Thursday 25th June 08:17

There is no evidence of red thread, I have never seen any red or pink tinge to the grass. Up here in Scotland it hardly ever gets warm enough for it to thrive. I am sure it has to do with the application of the treatment which in hindsight wasn't the best idea at this time of year. I take your point about not needing the moss killer or weed killer elements. It was what I had to hand. I will just use a nitrogen fertiliser in future, once I get the grass back to a reasonable state. I will also change my watering method to early morning and not every day to encourage deeper rooting. Thanks for your help.

Update. The grass was completely dead in these areas so I had no choice but to re-seed them. It's well wet today so hopefully that will get the seed started and in a couple of weeks I might have grass there again. Still a puzzle why it died.

[Dr Mike Oxgreen]

taxboy said:

Simple question regarding scarifying - after scarifying and overseeding does the lawn need top dressing with soil every time this is done or only if there are large bare patches

I always find I get much better germination by covering the seed with a thin layer of cheap compost. I think it improves contact between seed and soil, and keeps a bit more moisture close to the seed. Only a few millimetres - any more and you risk smothering the seed.

[morfmedia]

Are we safe to fertilse at the moment? Forecast for London has a 30% chance of rain tonight and then dry until next weekend then dry again. I have Lawnsmith summer fertiliser which is a slow release product.

[dhutch]

morfmedia said:

Are we safe to fertilse at the moment? Forecast for London has a 30% chance of rain tonight and then dry until next weekend then dry again. I have Lawnsmith summer fertiliser which is a slow release product.

I would hold off if the lawn is too large to water on the basis, wait till it's more certain. But interested in others thoughts.

[ChocolateFrog]

Where is the best place to buy loam soil for top dressing? I probably need a ton.

I'm in South Yorkshire.