retired strawman
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Question on grass clippings and straw ratios

I am one of your new guys for the coming year. I have 2 main ingredients for composting, fresh grass clippings and grass seed straw. I have read on some sites that these two sources should be mixed 50-50 or 60-40. Also read that the proper composting ratio is about 30:1. Most sites put a reading of grass clippings at 20 and straw at 75. My math tells me that to get a 30:1 ratio I need 6lbs of grass clippings for each lb. of straw. Did I miss something here? What do my neighbors here on this forum recomend?

DoubleDogFarm
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8)
Last edited by DoubleDogFarm on Sat Mar 31, 2012 11:55 am, edited 3 times in total.

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rainbowgardener
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It's both more complicated than that and more simple than that.

This link:

https://compost.css.cornell.edu/OnFarmHandbook/apa.taba1.html

shows typical C:N ratios of a variety of compostables. It shows grass clippings having a range of any where between 9 - 25 (C:N). It lists several different kinds of straw, I don't know which kind you have. So C:N could be anywhere from 48 - 150. So if grass clippings were 25 and straw 48 and you wanted a ratio of 30, you would use a little bit less straw than grass. If the grass clippings were 9 and the straw 150, you would use 3 times as much grass.

The trick is IT DOESN"T REALLY MATTER! :) It will compost anyway. It isn't rocket science. So mix it more or less 50:50 ish and see what happens. If it starts to get slimy or smelly or matted, you have too much grass. So you add more straw, turn it a bit, and it will be fine. If it is just sitting there, not breaking down, it has too much straw and/or not enough water (remember it needs to be kept damp to work). Add some water and more grass, turn it a bit and it will be fine.

But I think you will get better composting and better compost (finished product) if you have more diversity of ingredients. Throw in your kitchen scraps and yard wastes!

I just put in what I have as it comes along, though I do always cover a layer of greens (kitchen scraps and weeds) with a layer of browns. But my pile tends to be more green in the growing season when I have tons of weeds etc, and fewer brown ingredients and more brown in winter when I have tons of fall leaves and fewer green ingredients. It works just fine either way!

toxcrusadr
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Good advice there from rainbow, I agree.

As far as diversity, in the spring I am forced to make some piles of fresh grass clippings and leaves just to get last fall's leaves used up. They are not very diverse, but I put whatever kitchen waste or spring garden cleanup waste is around into those piles and the compost comes out fine. Maybe the micronutrients are not as rich and diverse as a pile with many different ingredients, but my plants don't seem to mind. :)

retired strawman
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Thanks everybody for the fast and great help. There will be a lot more than the grass clippings and grass straw going into those bins. We have quite a pile of kitchen scraps from the fall and winter. There is a chicken coupe that the previous owners never cleaned out, We have a llama so just before I mow the grass I go out to get 2 five gallon buckets of llama pellets to mix in. When my better half weeds the flowers and garden all of that gets run thru the lawn mower when we mow the yards.

The grass straw that I use is Ryegrass and Fescue. Maybe Oregon State University can help me narrow down the Carbon number on them. Really looking forward to Spring and to get started.
Thanks Again,

rot
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..
Sounds like that straw you're thinking of could be green. You might start thinking about browns. Shredded paper might be the handiest brown type stuff about. Keep an eye out for leaves. Run the leaves through your mower too.

You've already started listing a whole host of other ingredients, mostly greens at a glance. I imagine that once you get going, you will find no shortage of things to throw in there.

Observe how things go, soggy messes with ammonia smells means you need browns and perhaps too much moisture. Turn and add browns. Cold and lifeless means too many browns and not enough air or moisture. Turn and add water while doing so. And so on.

Observe and adjust.

to sense
..

retired strawman
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I feel I need to clarify about the grass seed straw that I am using for my browns. In the Willamette Valley where I live, farmers raise lawn and pasture grasses for seed. In fact 90% of the worlds supply of grass seed comes from this valley. After the seed is removed from the plant with combines the dry straw is dropped in rows and then baled with both 3-tie and big (4x4x8) balers for export to Korea and Japan to feed their livestock. The valley exports about 500,000 tons of this stuff a year. I have worked in this industry for over 25 years. My sons and I actually own a press facility that compresses this straw, loads it in 40' containers and markets it to foreign buyers. It is straw, just like oats, barley, and wheat after the kernels have been removed. It has a protein value of 6-9% and it is baled at 5-12% moisture. Hope this helps shed more light on what I am using to mix with my lawn clippings.

dustyrivergardens
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I just think of it as well let say 10 pounds of greens and 10 pounds of browns that is perfect. the green side is heavy the brown side light so it will take about 4 times the amount of browns to reach that 10 pound mark.

greenstubbs
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Everything you wanted to know about Compost see, https://www.klickitatcounty.org/SolidWaste/default.asp?fCategoryIDSelected=965105457
Happy Reading.

toxcrusadr
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Thanks for that description. It does sound like what everyone thinks of as straw, which is definitely a brown with respect to composting.

Let us know how this is going for you!

estorms
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Compost is not complicated. I just use what I have when I have it. I rarely turn it except when I put kitchen scraps on. I don't like their looks so I put something over them. The following spring, I use it; whatever its' condition. The plants seem to like it. We bought our retirement place last year. I have eight acres, a small tractor, and a pick up truck. We are not there full time, but I spend most of the spring and summer. What more could a gal ask for?

rot
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What's the difference between straw versus hay?
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applestar
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The way I understand it --

Straw is the remainder of the plant after grain is harvested. Typically this is done after the plant has finished growing and browned all the way to the grains. They are considered a BROWN. They can contain leftover mature grains/seeds

Hay is green grass and other green forbes (often high N legumes like alfalfa and clover) in varying stages of maturity that have been cut and dried. They are considered a GREEN though some hay are more browned stuff than others and there is a HUGE variation in quality and nutritional levels since they are cut several times during the season and each cutting represent different growth stages as well as species. They can contain nearly mature seeds (highest in nutritional levels) as well as mature seeds of desirable as well as undesirable species.

toxcrusadr
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Funny, I just posted the same answer to the straw/hay question in a different thread.

rot
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Thanks to both.
..

schierling
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I agree, I don't think it matters either, I have had good luck with compost, even though I am doing nothing scientific.
rainbowgardener wrote:It's both more complicated than that and more simple than that.

This link:

https://compost.css.cornell.edu/OnFarmHandbook/apa.taba1.html

shows typical C:N ratios of a variety of compostables. It shows grass clippings having a range of any where between 9 - 25 (C:N). It lists several different kinds of straw, I don't know which kind you have. So C:N could be anywhere from 48 - 150. So if grass clippings were 25 and straw 48 and you wanted a ratio of 30, you would use a little bit less straw than grass. If the grass clippings were 9 and the straw 150, you would use 3 times as much grass.

The trick is IT DOESN"T REALLY MATTER! :) It will compost anyway. It isn't rocket science. So mix it more or less 50:50 ish and see what happens. If it starts to get slimy or smelly or matted, you have too much grass. So you add more straw, turn it a bit, and it will be fine. If it is just sitting there, not breaking down, it has too much straw and/or not enough water (remember it needs to be kept damp to work). Add some water and more grass, turn it a bit and it will be fine.

But I think you will get better composting and better compost (finished product) if you have more diversity of ingredients. Throw in your kitchen scraps and yard wastes!

I just put in what I have as it comes along, though I do always cover a layer of greens (kitchen scraps and weeds) with a layer of browns. But my pile tends to be more green in the growing season when I have tons of weeds etc, and fewer brown ingredients and more brown in winter when I have tons of fall leaves and fewer green ingredients. It works just fine either way!



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