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Will mulching over hard compacted soil help it to soften?

Posted by viche 7a MD (My Page) on
Mon, Jul 13, 09 at 11:54

I haven't mulched my beds for a good 2 years. Since then the mulch has pretty much been broken down or blown/washed away in many areas. The soil in those areas is now tan, hard-packed dirt. I really don't have the time to add organic matter and till all the beds, not to mention the damage it might do to plant roots that are now closer to the surface.

Do you think if I add 3" of mulch over the dirt, it will eventually make the dirt softer and more absorbent again?

I was going to use bark mulch to prevent nutrient leeching from the soil, but now I'm wondering if the extra activity necessary to break down heart wood mulch would actually increase natural aeration in the soil as microbes work to break the wood down. I could also spray some liquid
fertilizer on the heartwood mulch to help the decomposing.

What do you think?

Thanks guys!


Follow-Up Postings:

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RE: Will mulching over hard compacted soil help it to soften?

Do you think if I add 3" of mulch over the dirt, it will eventually make the dirt softer and more absorbent again?

If you're lucky and you have time to wait.

Dan


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RE: Will mulching over hard compacted soil help it to soften?

I have found that shredded leaves (plus I use an initial layer of newspaper) is really good at retaining moisture (and weed prevention!) and therefore 'softening' the soil fairly quickly. Maybe a month or less, depending on rainfall/irrigation, etc.


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RE: Will mulching over hard compacted soil help it to soften?

I think I have to much area to do to add a whole layer of leaf compost/newspaper plus mulch. Do you think either bark or heartwood would do a better job of softening the underlying soil?

Thanks


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RE: Will mulching over hard compacted soil help it to soften?

I used gypsum to sweeten an area of clay sod we plowed into a garden a couple of months ago and now it's powdery and very easy to cultivate. Also, used it when planting some new fruit trees. Was told by a local gardener to use it each spring.

Here is a link that might be useful: Gypsum


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RE: Will mulching over hard compacted soil help it to soften?

good to see someone still using gypsum, though for me it is more a clay breaker(well aware it doesn not work on all clays but most clays i ahve been reliably told) than a sweetener that jobs belongs the the dolomite lime.

any yes mulching with hay will bring results and should do pretty quickly if as you say the medium was a viable medium at some stage, to make it even better introduce some organic matter compost of some sort under the hay(even if you were to buy one of those supposed organic chook pellet manures or any bagged manure), the worms will return quickly as will all the organisms. i would be expecting a big turn around in around a month.

len

Here is a link that might be useful: lens garden page


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RE: Will mulching over hard compacted soil help it to soften?

Thanks for the suggestions, but I think you guys are going a bit over my head. I don't have the strength, time or money to really work any substance into the soil. I also don't want to spread hay all around my house. I'd like to just do a mulch that looks good and might help the soil get soft again. It was once good soil, but the exposure has just turned it hard. Since it seems all the really good solutions involve more work than I am willing to do, I'm really down to the standard mulch selections, heartwood or bark. Once takes nutrients from the soil and breaks down, the other not so much. Do you think either would result in more activity in the underlying soil causing it to break up?

I need to decide by tomorrow! Thanks.


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RE: Will mulching over hard compacted soil help it to soften?

I still suggest that gypsum be spread on top of your area, then if you want add the mulch. Just get a bag of gypsum and cover your ground with it...doesn't even have to be raked in. Mother Nautre, that is if you have rain, will do the rest. Otherwise water it good periodically. The gypsum will definitely help break down the compact soil and make it easier to cultivate. The mulch will make it look presentable.


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RE: Will mulching over hard compacted soil help it to soften?

I still suggest that gypsum be spread on top of your area, then if you want add the mulch. Just get a bag and cover your ground with it...doesn't even have to be raked in. Mother Nature, that is if you have rain, will do the rest. Otherwise water it good periodically. The gypsum will definitely help break down the compact soil and make it easier to cultivate. The mulch will make it look presentable.


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RE: Will mulching over hard compacted soil help it to soften?

Its entirely a matter of opinion but I think evenly applied hay looks pretty good as a mulch. Its all about your frame of reference I suppose. Woodchips, especially darker ones, may have more of that freshly tilled soil look many gardeners love. But if your into mulching bare soil is likely not the look you want.

How big of an area are we talking about? If you are having a few yards of mulch delivered and dumped next to, or even onto your bed, spreading all of that around is going to be way more work than forking and spreading some hay. Cheap mulch hay may even cost less than wood/bark chips.


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RE: Will mulching over hard compacted soil help it to soften?

Strange, I posted a response earlier and instead it is duplicating jas's post...oh well.

Where do I get gypsum, how much do I need, oh and what exactly is gypsum? Any negative plant/human effects?

I just don't know anyone that mulches with hay around here. I don't think they even sell it. I look the finely shredded dark wood mulch look. I think hay would look dray and light and would blow away in a good wind storm.

The area takes about 5 yards of wood mulch.


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RE: Will mulching over hard compacted soil help it to soften?

Adding gypsum to any soil will do little unless that soil is sodic and sodic soils are found where the amount of rainfall is too little to wash the salts out od the soils. Maryland is not one of those places.
Depending on the type of soil you have, and I have found, depending on the type of material you mulch with simply plunking some mulch on your soil could loosen it. My experience is that shredded leaves work best on most any clay soil, although there are some, as we found with the black clays around Lansing, that no mulch will help and you need to till some Organic Matter into those soils first. Wood chips might do the same, but not nearly as fast as shredded leaves and I have not seen wood chips loosen clay soils much yet. It may take more than someones lifetime.


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RE: Will mulching over hard compacted soil help it to soften?

Gypsum likely won't work where you are located. I return to my very first reply above - nothing has changed.

Dan


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RE: Will mulching over hard compacted soil help it to soften?

Interesting the responses about gypsum for your soil in MD but it seems to be working for me here in Illinois. Now, who is to know if I might have had the same results without gypsum (purchased at Menards) but I have a flourishing garden after tilling a large grassy area of predominately clay. Could be the work of MN's elements prior to our plowing that is giving me these results.

I do like what I'm reading about no till. I haven't gardened in Illinois for years (been a resident of TX about 15 years) and never have gardened in this area of the Midwest. I'm builidng a compost pile and plan to cover my newly plowed garden this fall with it along with leaves, grass clippings and plenty of manure. Might even add some shredded newspaper

Thanks for all the tips on no till gardening.


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RE: Will mulching over hard compacted soil help it to soften?

Gypsum has specific chemical reactions to trade ions with ions in the soil. If those ions are not present the purpose of the compound is defeated, and the money spent is wasted. Specifically wrt flocculation and soil structure, the trade happens in basic or sodic soils. This is not to say that the ion trade doesn't have benefits, but it is not what the OP is looking for. Bottom line: sprinkling and walking away won't loosen soil.

Dan


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RE: Will mulching over hard compacted soil help it to soften?

Thanks for all the info. I think I'm going to go with 3" of wood mulch and see what happens. I don't have the time or energy to do multiple yards of leaf compost...and I don't think it will last as a mulch.

Only question remaining is which wood mulch to use: brown dyed green heartwood vs partially composted heartwood, vs bark mulch. Which will stimulate the most action in the underlying soil? Need to decide today.


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RE: Will mulching over hard compacted soil help it to soften?

"Do you think if I add 3" of mulch over the dirt, it will eventually make the dirt softer and more absorbent again? "

Yes.

One or two growing seasons and the mulch will be composting in place. The organic matter will eventually be worked into the soil by rain, frost, freeze and thaw...


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RE: Will mulching over hard compacted soil help it to soften?

jas, if you talk with the people at your local office of your University of Illinois USDA Cooperative Extension Service they will tell you that gypsum has no affect on your soil, no matter what you might think you saw. The people that mine and sell gypsum will tell you that it will correct many soil conditions, because they want to sell you their product.


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RE: Will mulching over hard compacted soil help it to soften?

Viche, if I am remembering correctly, pine bark might be a good choice for you. I think it will tie up less nitrogen, as it breaks down, than heartwood. What did you use in the past that kept the soil soft?


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RE: Will mulching over hard compacted soil help it to soften?

  • Posted by jolj 7b/8a-S.C.,USA (My Page) on
    Sat, Jan 22, 11 at 13:27

I never had a problem with nitrogen or plants doing poorly because of to much nitrogen in the beds, so I think some of us put to much stock in the tie up of nitrogen. Much like the
gypsum to loosen all clay soils.
But that is in my garden, I do not know what happen in your soil.


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RE: Will mulching over hard compacted soil help it to soften?

I remember watching Gardening Naturally one day, and Elliot Coleman took on a challenge to change hard pan into good soil within 5 years, using only organic means.

He did it in one.

He used lots of green manures. He never tilled. His goal was to get plants that reached into the soil with their roots and broke it up, each one more invasive that the last.

One thing he talked about was Daikon radishes. He said the roots on those will get very big. Then you just let them decompose in the soil for organic matter, along with everything else. Alfalfa is also good, bringing nitrogen, michorrhiza (pretty sure that is not spelled correctly), and deep root systems.

He is my hero. :o)


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RE: Will mulching over hard compacted soil help it to soften?

jolj, excess Nitrogen in soil will interfere with a plants ability to uptake other necessary nutrients and will create lush green growth that is very attractive to insect pests. An excess of any nutrient in soil will inhibit a plants ability to uptake or properly utilize other, necessary to good healthy growth, nutrients.


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RE: Will mulching over hard compacted soil help it to soften?

I'm sure different areas and soil types vary but my experience with mulch here in Austin, TX has been very good. Trying to make good gardening soil here takes effort. We're on scrub land to begin with, not good for much except raising really hardy cattle. Vegetable gardening is what I'm working towards and it's a harsh learning curve when you've got 3" of soil on top of limestone bedrock if you're lucky.

I like no till, I like the idea and concept. If you have time, it's great. Nothing will take patience like trying to build soil no till in our area. We have plentiful cedar mulch and I use it extensively on my yard.

The best way I've found in our climate, soil type is to prep a garden by tilling the entire area well and then adding copious amounts of finished compost and tilling/mixing it. Then you lay out your garden plots and with a shovel, scoop that now refreshed/tilled soil onto what are the garden beds and leave the path bare. So you've taken that 3" of soil and Very quickly turned it into a workable 6" but only in the beds.

I then go in and put mulch heavily in the paths. We're talking 6" at least, if not more. I pile it on, it makes an excellent path to walk on, it's good for your back and it holds a huge amount of moisture when it rains which is lacking in our area. Over time this organic matter will break down and several years later you could grow vegetables in the path if you wanted.

No till will work, it just takes a huge amount of time. Green manure works wonders. Leguminous plants like clover, vetch, peas and the like can do wonders over time. Season after season you could turn poor soil with no compost very fertile. If you cut down the green tops you can use them as a mulch as well.

Using daikon and root crops to open the soil works as well. Masanobu Fukuoka was a huge proponent of using radish like daikon for this purpose. It's fast growing and if you planted it repeatedly it'll open the soil the way a plow would. It takes time, but if you were working on a large area or acreage it's the slow steady pace of changing land.

If you have issues with weeds you can put down cardboard underneath mulch in pathways to smother them. Several layers of cardboard will break down rapidly and in our area we use it to smother bermuda grass. Even if we get a bunch shooting up on top of mulch we've put down we'll put cardboard down and mulch heavily...again. In the garden beds themselves if we have issue I'll do the same thing on the beds but with newspaper. I cover the garden bed, then put 3" or so of compost on top of the bed to smother out the bermuda grass instead of trying to weed them. It's less work, works better long term and builds up the soil.

So, long story short, mulch is great. Use lots of it. It takes time to break down but I've seen no downside to it. It improves soil, holds moisture, provides habitat for beneficial bugs and worms who do the work of improving soil for you.


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RE: Will mulching over hard compacted soil help it to soften?

viche, I'd go with the partially composted wood mulch if I wanted the results that you are looking for. It will probably disappear into your soil in a few months. Keep adding that product on an annual (or more often) basis, along with compost and other organic (meaning that it was once alive) substances.

The worms and other soil borne critters will do a good job of getting the mulch material into the soil.


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RE: Will mulching over hard compacted soil help it to soften?

Hmmm, this thread is 18 months old, I wonder how Viche's garden is growing.

While mulch will certainly help most soils to soften with some moisture, I haven't heard anything about the type of plants the OP was growing or what type, if any, fertilizer was being used. Not going to have much of a garden with infertile soil even with mulch - at least for a long time.

Compost, leaves, grass clippings work as a mulch with more nutrients. Layer of bark or other woody mulch on top to keep moisture in and for esthetics.


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RE: Will mulching over hard compacted soil help it to soften?

Remember "It Never Rains In Southern California" by Albert Hammon? He was not total correct, as it almost never rains in NoCal too, not for 8 months of the year anyways. And that has a big effect on my mulching over hard compacted soil.

Every few years, I had local tree companies send a truck load (14-16 cu yards) of freshly cut freebie wood chips to my house. I then age them a few months in the rainy winter before applying them all over the yard as mulch. What they delivered have shredded leaves, wood chips, pine needles etc., a decent mix of green and brown. After steaming for 2-3 months, most of them turned totally black.

Guess what? during the dry summer months, the mulch basically bask in the sun and the dirt under them remain dry and rock hard. I have been doing this for quite some time and my dirt is still hard, very hard. I think for mulch to soften the clay, it takes long time and need moisture to do their magic.

Next round, may be I have the tree companies send the freebie in summer, and r put a sprinkler on them while they age. Then apply them before the rainy season.

Just my experience.


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RE: Will mulching over hard compacted soil help it to soften?

"I think for mulch to soften the clay, it takes long time and need moisture to do their magic."
An astute, and very true, observation. If there is little to no moisture in the soil putting mulch down will not, magically, moisten that soil and since the Soil Food Web (the wee critters that will digest that mulch) need moisture to work in the absence of moisture they won't.
On occassion, soils lacking adequate amounts of organic matter have no members of hte Soil Food Web present and putting organic matter on top of those soils as mulch, sometimes, does not always get that OM into the soil because there is nothing there to move it into the soil and tilling mayh be required, initially.


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RE: Will mulching over hard compacted soil help it to soften?

Living in the Phoenix area the abundant sun and stifling heat turn newly watered soil into baked clay in a matter of days. So the problem of hard compacted soil is continual in the absence of a well-mulched bed. Is this the type of soil that gypsum would help most? I've got to do something because I don't think that even drip watering is allowing enough moisture to penetrate greater than 5".


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RE: Will mulching over hard compacted soil help it to soften?

azmab. I have been using drip and low pressure spray, . They really didn't do much, going down 5" may be possible but only in very limited area.

I am very tempted to remove the wood chip mulch, rototil my 30'x5' annual bed with gypsum, compost and chicken manure. Then cardboard the area before returning the removed wood chips back. Currently, the dirty under the wood chips are rock hard.

This bed was tilled 6 years ago before I read that rototilling is no-no as it breaks up the dirt structure too much. I don't know if I will till the bed partly because of the soil structure issue and partly because I do have thriving petunia in this bed, two years old and huge. Some branches are more than two feet long and full of flowers. Hate to deny the petunia's chance of coming back for their 3rd year.

But I will try gypsum at some point. I am tired of rock hard dirt.


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RE: Will mulching over hard compacted soil help it to soften?

Soils in Arizona are known to be sodic due to the normally low rainfall so yes gypsum may be of some help.


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RE: Will mulching over hard compacted soil help it to soften?

Thanks. I think I'll give it a try.


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