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Mulching with lawn clippings: Oh the joy of dessicated grasses!

I love grass clippings! Can't get enough of 'em.
That's not just me being rhetorical but a statement of fact: I can never get enough grass clippings. Grass chopped up by mowers maketh up my garden. Year in  year out in all weathers I've collected and  distributed cut grasses atop my garden beds. 
This is mulching per the good graces of the local  lawn mowing industry. I have guys working for me gratis.
I save them tip fees and they deliver me mulch. All I have to do it barrow it from nature strip to garden bed.
I've been lawn clipping dependent for years. This is my second garden built from lawn detritus.
The sheer scale of the amount of cut green material I've thrown on my garden beds may have to be my little secret because dessicated grass quickly rots down to a shadow of its former self. 
It's a total Sisyphusian task. [See image] I'm always just one step ahead of exposed raw earth...which I just gotta cover with still more mulch material.
But after a few years and all those wheelbarrow loads ... my yellowish almost greyish sand has changed to dark grey and black loam while recruiting biota big time.
En route I've learnt a thing or two about mulching and mulching with grass clippings especially.

Lesson #1 : Plop Plop

When distributing grass clipping atop the garden beds throw it down in handfuls so that the surface of the mulch is undulated  and pitted. You don't want a flat surface or even a convex one. You want your mulch to break down unevenly so that any precipitation enters the mesh of  fibres and percolates through to the soil underneath. Undulation rules.

Lesson #2 : Tease it up

Depending on the weather and the condition of the grass on its arrival, the clippings may tend to lock together and create a sort of mat. This can cause the soil underneath to heat up and may prevent moisture seeping through. So you need to tease up the grass cover  as though you are brushing it. Separate the fibres, fluff  up the grass hairdo and aerate the mulch. I use my hands and pull any weeds  at the same time.

Lesson #3 : No dust

In dry weather conditions cut grass mulch will turn to dust. This is all part of the break down process. The solution is to cover the pulverised grasses with fresh mowings. But because the weather is indeed dry -- and we're talking June and July (here in South East Queensland)  for example -- your grass clipping supply may be very low indeed because grass doesn't grow without rain and if it don't grow it don't get mowed and your supply will also dry up.
So you need to plan ahead and as the dry conditions kick in you need to deepen your mulch layer: pile up the grass so that you have leeway in the break down. Watering the mulch will also keep down the penchant to dust and ironically slow down the process .

Lesson #4 : Fertilize

You can read the stuff on the N:P:K of grass clippings and angst over it if you like. Since I'm reliant on the green stuff I've experimented with many throw-on additives deployed to fertilise the garden beds. But I always suspect that I am being wasteful of my resources. It just sits there atop the beds like dollops on a carpet...and dries out to pith.
This is why I seriously explored trench/pit mulching in preference to demanding too much of my sheet mulching habits.Nonetheless, after some experimentation I prefer to 'top dress' my mulch with Blood and Bone (+potash). After sprinkling Blood and Bone over the mulch beds, a quick fluff up of the grass clippings will distribute the ground particles to the soil below. Preferable to 'hosing in'.

Lesson #5 : Weeds

If you are gonna use grass clippings as mulch you are sure to be importing weeds into your garden. 
Fact.
My experience has been that if you keep layering on the cut grass you are usually one step ahead of the weeds as you shade them out. But they occasionally will root and they will spread. 
Every now and then I pull them...but the norm is that one species is the  feral one so you get to know its habits. That's the irony you see: I may get grass clippings mowed from a wide local regional arc, but the weeds I get are usually just the one or two varieties.
Compared to what I got when I laid out locally collected manures -- especially horse -- give me the grass clipping weeds anyday. I got some real nasties from the manures taken from local farms.In comparison, my grass harvest was benign. 
This is one reason why I now prefer to bury my manures in pits rather than let them rest on the surface of the soil.

Lesson #6 : Seedlings

My mulch layer is preferably deep. So when it comes to planting I find that you need to create a pit in the mulch in order to plant your seedling or seed. Pull the mulch aside, embed your plant, and...this is where a problem may kick in. 
Ideally you'd flag your seed or seedling: but so far I've not found a foolproof method for doing this. I don't block plant, so the bigger the plant is/the more chance there is that I'll continue to know it's there. So planting in mulch has its drawbacks.
My garden beds are 'busy' ...and there isn't much order about them. So marking off what I do -- so that I continue to register the fact -- is still a problem. This is exacerbated by the thickness of the mulch layer. 
Nonetheless, a deep mulch layer will also serve as a wind break for your seedling., so with that in mind you could look at your plantings as taking place at the base of a pit  walls all around..

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Comment by Christa on November 12, 2018 at 20:40

You do well with your grass clippings mulch, Dave, but I worry a bit about doggy poo and weed seeds and pesticides.  If you ask for clean clippings, then you have to rely on contractors honesty.

We are just starting to gain some control over weeds,  Most of my neighbours use poison on their lawn weeds, which is a pity.  Cane mulch appears to be our answer.

If I had my way, we would have no grass or lawn at all, the whole yard would be mulched and made into a forest walk through fruit trees and tropical plants and grasses.

Comment by Dave Riley on November 12, 2018 at 4:11

Tons? That varies according to moisture content & freshness. Volume is a better judge. I just carted in a pile that was 1.5 metres high.

Carting grass clippings from A to B is my cheap version of going to a gym.

While I use a wheelbarrow, I find it more efficient to load 3 big plastic buckets with grass, then carry them outback in the wheelbarrow. That way it is easier to distribute the mulch exactly where I want it instead of double handling.

I used to load using a garden fork, but now I rely on gloved hands.

After 8 years of working with the stuff you develop a skillset.

Comment by Jeff Kiehne on November 11, 2018 at 19:40

How many tons of grass do you think you receive in a year.

Comment by Dave Riley on November 11, 2018 at 19:26

Thats's why the mower men like me: no trip to the tip/no trip fees/close by.

I do my bit....

Comment by Jeff Kiehne on November 11, 2018 at 19:11

Brisbane City Council have over 90,000 green bins to pick up green waste $83.92 per year  that is about $7.5 million dollars to pick up 23,000 tons of green waste about $300 a ton that is expensive grass clippings better to compost or put in the general waste bin green waste disappears quickly.

Comment by Dave Riley on November 11, 2018 at 18:19

Cardboard? Nothing that rots leaves my place. I collect cardboard from fam and lay that down too. You don't really need to shred these things as the creatures of the earth will do the work for you.Mulching is all about patience I reckon.

Indeed, the core disadvantage of grass clippings is that they rot so quickly.

Comment by Jeff Kiehne on November 11, 2018 at 17:36

Have you tried cardboard  i put paper and cardboard through a shredder and mix with the grass clippings and other green matter a large box has some weight and easy to get.

Comment by Dave Riley on November 8, 2018 at 22:25

The years come and go...and I mulch on.

As I speak I am now mulched up to pussy's bow. It's not always like this but now that I grow and harvest Vetiver and my grass clippings keep coming I have depth to my soil covering and an assured supply of vegetative matter

if I place a ladder on my beds and climb, the ladder sinks  deep into the soft earth below. I now garden on a sponge.

This carpet is such that I have no issues with tramping over my beds to garden as any  footfall in the mulch springs back.

I therefore have less need to waste space creating pathways.

As for soil life this garden is so worm friendly that they are teeming. Every trowel full of soil will disturb earthworms.

Unfortunately grass clippings break down very quickly -- whereas the cut Vetiver should last around a year on top of the beds. For now I'm hoping to use a mix of the two.

In time, I may stop the grass clippings in preference to Vetiver mulch because I grow the Vetiver as a hedge around every bed.

So easy to cut and drop.

No more barrowing from the street.

Comment by Dave Riley on May 4, 2015 at 3:22

UPDATE A YEAR LATER:

Elaine Coolowl took this photo in my garden during a recent BLG visit:

It shows how I'm currently sowing seeds among the mulch.

  • I part the grass clipping in a line and tease up the underlying earth where I intend to sow.
  • I then lay down a short length of old hose to mark my planting line.
  • Using the hose as a guide I hand sow (with tweezers!) each seed at intervals along the hose line.
  • I then usually add a label and leave the hose in place until the seedling emerge.

To plant single seedlings, I part a hole/depression in the mulch for planting and usually mark the spot with a few upright twigs or a cut tile.

When planting bush beans, garlic cloves or tubers and the like buried and in situ, I create a rough perimeter with cut hose pieces and plant inside that  then label. I've used aluminum edging in the past to create separate planting  zones, but I find the recycled garden hose a much more flexible and efficient method of flagging what's planted where.

Needless to say, using garden hose enables me to run seed lines of any shape -- circles, straight lines, curves, etc -- to suit the available space in each garden bed. I also find that the line registers in my brain where I plant each seed as I plant each one so I'm less likely to plant them too close together. I plant one side of the hose  before doing the other rather than alternating. This way there is less waste and later need for thinning.

I have cut short hose lengths of a metre or so  and set them aside as  planting tools.

Comment by Dave Riley on May 2, 2014 at 12:06

Perhaps...but I suspect they could get a bit too wet if they aren't thoroughly dried out first.You can see this effect when the fruiting bodies of cucumbers , tomatoes or pepinos rest atop the grass clipping mulch.It's very sweaty and moist underneath sometimes, esp in wet weather, to the detriment of the harvest.

So I'd always tease up the clippings if I was growing plants inside them...and you'd need to look to the fertiliser mix, of course. While formally grass is grass and sugar cane and your local lawn should have everything in common the cane residue isn't dessicated the way lawnmowers chop up grass. Some lawn mower pros -- in order to get the work -- will cut the grass when it is very short so you really get a short fibre mix of cellulose.

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