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sheet mulch and horse manure questions

Posted by Waterfront (My Page) on
Tue, Aug 23, 11 at 15:36

Hello all-
I'm new to posting on GardenWeb and this might not be the perfect location to post this, pls let me know if I should also post it elsewhere.

I�m looking for some input on my garden revamping strategy�
I�m looking to remove all the grass in my front yard (this is about 3000+ sf) and replace with all tough, drought tolerant native perennials and shrubs. I am in the District of Columbia.
So�my strategy is to sheet mulch the entire front yard doing the following:
*cut lawn uber short
*dump on aged horse manure now (so, September)
*wet newspaper or cardboard layer
*purchased compost on top as much as I can afford based on the amount of horse manure
* in the SPRING (so, April/May or 6-7 months from now) plant a boat load of plug plants at a high density

The issue for me due to the size of this endeavor is cost. I have access to aged horse manure for free� Buying compost is pricey at the amount i need..but I will buy it if I really need to. I�m looking for some input on the horse manure part of the strategy as I'm pretty urban and horse manure is new territory for me�
*any chance I can use all horse manure for this in lieu of compost?
*I�ve seen recommendations for the weedblock layer to be both below or above the manure. Seems to make more sense to me to be above to block any errant whatnots from the manure. Thoughts?
*I could also add leaves in the fall on top�good idea? Should they be shredded? Do I need to mix them in? Mixing them sounds like more work that I won�t be interested in after spreading 10+yards of manure.
*I can get wood chips for free...but i think they are not a great idea, but maybe a small dose might be OK. Thoughts?
*If i buy aged manure is 6 months of further aging enough insurance again scalding my starts?
Any suggestions to make this better (or to limit my chances of absolute failure) are greatly appreciated!!
Best, Waterfront

Follow-Up Postings:

RE: sheet mulch and horse manure questions

I would be very concerned about weed seeds from horse manure. Apparently horses let far more viable seeds through than cows. Or maybe it's the diet, I don't remember. But you are likely to have a full garden of whatevers without planting anything...

Is your yard sloped at all? What's the chance of erosion happening on all that bare composted ground during the winter rains and snows? Some wood chips would be good for that, as long as you're not planning to till the entire thing in the spring, which would bury the wood chips, not a good idea.

Other than that, the concept sounds great.

RE: sheet mulch and horse manure questions

I would talk to your source of manure and inquire about the horse's feed to see if there is any possibility that the feed or beeding has been sprayed with an herbicide at all. I went to a friend's house and shovelled free manure into my truck for my veggie garden. My friend was not aware that the horses feed had been sprayed with an herbicide that can persist even after coming from the back-end of a horse, aging in a pile and then aging further in a garden bed. This will take much time and/or money for me to remediate. Not to mention, no much longed for tomato sauce.

Before I learned this lesson, I obtained more manure from a neighbor and I will absolutely be performing a bio-assay test to determine if this manure is contaminated before I spread it on my gardens.

RE: sheet mulch and horse manure questions

tishtoshnm - what a DOWNER! i'd call that a disaster...i'm sorry you have to deal with that. i never would have thought that could happen. how did you find this out? did nothing grow when you spread it?

toxcrusadr - thank you, i will have to think about the seeds. i think maybe i will use some manure with a heavy, heavy paper/cardboard layer and then a thicker top layer. but like i said, the cost is an issue. i don't plan on tilling. my yard is close to dead flat, so i don't have to worry about erosion.

ah, decisions...decisions...

RE: sheet mulch and horse manure questions

It was absolutely heart breaking. The herbicide only works on certain plants so those that were sensitive to it showed deformities and the fruit was severely deformed. In the vegetable world it affects legumes, night shades and things in the sunflower family. Other areas where we spread it with perennials did not do too bad but it did adversely affect dahlias. I had started a thread on here called contaminated soil where people included links on how to test for the herbicide.

One thing you might consider is whether or not your plants will even need the horse manure if you are planting natives. My soil and climate varies greatly from yours but one danger with native plants for me can be over improving the soil. Not all plants benefit from manure. For cost effectiveness, we obtain as many coffee ground as we can from Starbucks to add to areas where we plan to build the soil as well as grass (as long as we know it has not been sprayed), leaves, whatever we can get our hands on. Good luck!

RE: sheet mulch and horse manure questions

Any organic veg grower needs to take time to read and understand the OSU PAPER. Trust me on this.


RE: sheet mulch and horse manure questions

  • Posted by pt03 2b Southern Manitob (My Page) on
    Thu, Aug 25, 11 at 7:45

I second Larry and add "Any organic veg grower and composter needs to take time......"

Be very aware of your source of compost feedstocks or garden amendments.


RE: sheet mulch and horse manure questions

Larry, thanks for that link. WOW. I learned a BUNCH.

tishtoshnm - i do have to be careful about making the soil too rich for natives. given what i am starting with (which has been tested and shows very little organic matter) i figure i can't really go too wrong. plus, the place gets so very dry and hardpack i figure i can't go too wrong in figuring im starting from zero. plus, if i really overthink it, i'll drive myself too crazy!


RE: sheet mulch and horse manure questions

You're on your way to success & won't fail. Layering materials will work without diggin' in!

You asked about using horse manure instead of buying compost -- that should work just fine. I've never bought compost and have several large garden areas built putting the partially composted manure on TOP of the cardboard. I rarely pick up fresh manure, but last fall purposely did that for 2 vegetable beds and to make a hot compost pile with my garden waste. The tomatoes are growing very well in those 2 beds this year and since the horse manure was just one of the layers along with shredded leaves, coffee grounds, grass clippings, garden waste, etc. I'm not having any sprouting of weeds or too rich soil for the tomatoes.

Shredded fall leaves would make a great top layer to the sheet mulch & should be herbicide free!

Also free are used coffee grounds from St*rbucks or ask at another coffee shop. Shredded paper would be a brown to compensate for the greens (coffee & manures).

Once the manure is the first layer the other materials on top smother any weedy things that might sprout up. I've done that using chicken, rabbit, goat, llama, & horse manures numerous times.

Here's a bed we made this spring using chicken, duck & rabbit manures from the pens in the background along with other compost materials (mostly composted horse manure + sawdust bedding plus used coffee grounds). Intially, it was mounded up highest in middle & higher than surrounding soil, but has composted down even more since this mid-July pic was taken.

One of my sources of horse manure feeds just beet pulp, oats, & alfalfa hay. If they feed grass or timothy hay you'll have more weed seed problems. You can't beat horse manure for volume even though the other manures are more potent. The horse manure might be best for your native plant project as once composted with the other materials it will initially be a bit rich, but will age more & become organic matter not necessarily fertilizer.

The most 'sprouty' has been the goat manure that wasn't composted at all prior & mixed with their spoiled hay bedding. When I transplanted I dug through the layers to part them & some of the grain & vetch seeds must have been brought to the surface. Still it's not a huge problem as I walk the bed frequently reaching in to pull & drop the seedlings. Some have escaped my eye until 12" tall & still pulled up no problem.

Hope that helps!

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