Lawn advice - dead grass

 

Hi,

I'd like some advice on lawn care.

I have worked hard to try and improve the condition of my lawn over the
last 2 years since I moved to a new house, with only limited success.
The lawn was full of moss and yarrow when I moved in and I have
successfully removed much of this through the use of feed and weed,
moss killer, scarifying, top dressing an reseeding. However, in
May/June last year and once more this year I suddenly seem to hit a
problem where by some 25-35% of the grass (possibly just the original
grass) appears to die (pale yellow/whitish) for no obvious reason. This
obviously makes the lawn look in poor condition which is annoying given
the work put in so far ! So, the question is why should this grass
suddenly die ?

Here's some more detail:

- Tha lawn is well protected from wind and receives sun for much of the
day. It is mostly flat apart from a drop between two levels. I never
water the grass (certainly not needed this year so far).

- In mid April I used feed, weed and moss kill (12% nitrogen). We had
two mild frosts after this application. However, the results after two
weeks were great with the whole lawn was looking extremely green and
growing really well. One issue maybe that I never really new how much
my spreader was putting down (no instructions) hence I may have over
done it, or underdone it ... could this be the cause ? I have a Scotts
Evergreend distributor so if anybody knows what the numbers 1-19
represent that would be useful :)

- I have a mix of weeds in the garden including clover, yarrow,
germander speedwell plus others. General impression I get is these
weeds indicate a lack of nutrition in the soil.

- There are areas which show up with Red Thread disease, I suspect more
so after all this heavy rain.  Does this indicate poorly draining soil
?

- The soil is chalky but not until 10-12 inches. On top of that is soil
which I think has an okay pH, although can't recall exact value.

- Newly seeded grass from this year is growing really well. I have used
standard family hard waring grass mix rather than the finer looking
grass that was already down (although I guess this may have just been
the same grass but poor quality).

- The lawn had been poorly maintained for years prior to us moving in.

- I have never aerated the lawn deeply. Those roll spikers never seem
much good and hand coring for a large lawn is a nightmare !

- I mow 1-2 times a week but suspect I have cut too much grass at times
as I have cut greater than 1/3 off at a time. I have noticed the tops
of the grass have browned, yet I have sharpened the blade twice already
this year. Exactly what is 'sharp' for a mower blade ?

I imagine the issue is general poor quality soil rather than one
specific issue, if that's the general view what's the best way to get
the goodness back in. Extra fertilizer applications, more top dressing,
machine based aeration ?

Thanks for any advice,

jed

 



Do you see birds pecking at the grass?  It could be grubs eating at the
roots, either charer grubs or leatherjackets.

http://www.rhs.org.uk/advice/profiles0402/chafer.asp

http://www.rhs.org.uk/advice/profiles0206/leatherjackets.asp  

 

WRabbit: I don't think I have chafer grubs or leatherjackets as the
dead grass is fairly wide spread rather than specific areas. I've also
not seen the birds pecking hard at the grass, just pinching my grass
seed I reckon! I've seen the damage the crows have done at my golf
course looking for leatherjackets ... and that's nothing like I have in
the lawn. I'll keep an eye open though as there are certainly grubs in
there, but not sure what type. Maybe I'll find out if I dig up a spade
cube and count the worms (keep the kids happy that one for sure) !

Rob: Thanks for the extensive advice. Think I'll try checking the worms
to see if the soil really is any good. The house is 8 years old so it
wouldn'y have been too long ago that the back yard was a building site
with the lawn rarely being tended to in that time. How to fix it will
no doubt be harder, the tea compost looks a little tricky as I can't
see an easy way to get lot's of air in to the mixture or what container
to mix suitable quantaties in. Have about 350-450m2 of lawn.

Me here: If the grass is diseased then I can't identify what it is as
it's so widespread hence my thoughts the soil just isn't that good. I'm
sure I have Red Thread disease but not sure if that would be lawn wide
yet and whether it's always accompanied by red mould type residue on
the grass, I only have some patches with this on it.

Everybody: Thanks for the mower tips, I have a tatty rotary mower which
takes for ever to mow the whole lawn and is long overdue replacement in
my mind (something bigger !). Maybe I should just go an buy a new blade
so it's balanced and sharp, they're not exactly expensive. I'll also go
pester the green keeper, but from what I recall I wouldn't even get his
corer through the garden gate !

Thanks

Jed

 



Not strictly true Rob,
If a Rotary blade is spinning fast enough it should throw the debris to the
collection bag without leaving trails.

When the clumps of debris are seen behind the mower or building up on the
wheels usually it means the exit route from the blade to the bag is
clogging. Shut down, clear and then continue.

Sharp blades will produce a cleaner cut, even on a rotary. Careful
sharpening of the cutting section of the blade produces a better cut,
cleaner debris removal and less susceptibility to leaf damage because it
cuts and doesn't rip. If sharpening yourself ensure that an even amount is
removed from each end of the blade as balance on small machines if essential
to prevent vibration damaging engine or motor bearings.

If there are small areas of waste left behind just set the mower to highest
cut and go over the area again. The vacuum effect will lift the debris
without any damage.

10 years on a Golf course as their mechanic looking after everything from
18" walk behind mowers to 8 metre wide fairway machines, both rotary and
reel type, gives an idea of what cuts well and what cuts crap ;-)