Confused about mulch

[AMKuska]

I'm sorry. Do you have a fire season there?

I wish I had weeds.....heading into a second year of drought....

 

[Ridgerunner]

I've been studying garden health a lot recently, and many places are recommending a mulch cover to help keep the soil warmth, water, and nutrients in, while also keeping pests out. I'm going to try mulching this year, but the different methods I've read have me confused. One recommends I use compost as a mulch, and others recommend things like straw etc.

I'm confused about using compost as a mulch. Compost to me is a soil additive, so isn't it then soil when you layer it on top? Won't it still run off if it's watered?

I'll give my opinion on a lot of this and some reasons why I think this way. It is my opinion and my feelings won't be hurt if someone disagrees. Well, not much.

The Devil is usually in the details. People often recommend doing something but if you don't know the details of how they do it you may do more harm than good. On the chicken forum some people say they put the stuff on their garden when they clean out the coop. When questioned they may say they compost it first, doesn't everybody know to do that? Or if they do go straight to the garden they only put it between rows, not on the plants. Some people clean their coop so often there isn't much poop in it so they may put it pretty close to their plants but for many of these I think it's more what they read somewhere than any real experience.. The details will get you. I've killed tomatoes by putting stuff from the chicken coop too close.

Not all compost is equal. If you make it in a way that you cook it from its own heat you can kill the seeds in it, but the compost I make doesn't come close to that. Maybe if I used a barrel composter where it gets turned a lot or just used things without seeds it would be sterile as far as weed or grass seeds. But I don't use seedless feed stock and I don't turn it nearly enough to cook all the seeds in it. So my compost will sprout if given a chance. So there is that to consider.

Will it run off if watered or you get a rain? I think that would depend on how you water or how heavy a rain, how level the ground is, and how it is spread (how thick?). Over time it will disappear, mixing with the ground underneath if nothing else.

to help keep the soil warmth,

Depends on the mulch. A black mulch will heat it up from solar heat. Spreading black plastic for a period of time is supposed to cook the seeds in the soil underneath. It will, but from what I've seen not very deep. Still, black plastic is often recommended as a way to heat things up for warm weather crops if you are further north. Sweet potatoes and peppers could benefit from that in northern climes. If your compost is black it could certainly attract heat if it is a layer on the surface. My compost is generally more brown than deep rich black. Maybe it's the materials I compost, my method, or maybe because I don't mix biochar in it. On the other hand if you use something like straw or wood chips that can insulate your soil and help keep the hot southern sun from cooking the plant roots.

water,

To me this should be a benefit of mulch. A layer of mulch should help keep the soil from drying out. A well drained soil is still going to drain, but mulch can reduce evaporation. It may help keep the soil from getting as hot, the hotter it is the more water evaporates. But also it can break up the capillary action that brings water to the surface where it can evaporate. I don't think compost as mulch would help much with that. To me a good mulch helps stabilize soil moisture, keeps it from fluctuating so much. Compost will retain moisture but I think it will do a better job of that of mixed with the soil and not just laying on top of the ground.

and nutrients in,

Not sure how much mulch benefits this. If you get a flood and soil washes away you loose any nutrients in that soil. But when I see this I think of leaching. As water passed through the soil it absorbs any water soluble nutrients, nitrogen for example. As it drains away it will carry those nutrients with it. I don't think it carries those nutrients with it when it evaporates and turns from a liquid to a gas. Maybe it helps in some ways I don't envision.

Once certain mulches rot they add a lot of nutrients to the soil. To me this is a huge benefit of certain mulches.

while also keeping pests out.

What pests are they talking about? Straw or wood chips and stuff like that gives some bugs like squash bugs great hiding places. I've seen the recommendation to not put mulch right up to the plant but leave a bare spot around the stem to protect them from critters. You can't see mole or vole tunnels. Some diseases live in the ground like blight, the spores can splash up on the plant in a rain or if you sprinkle water. Mulch can help stop that. Mulch right up next to the plant may keep it wet so certain molds can grow. It's a mixed bag. Compost as mulch may help with some of that but not with others.

I think compost should have another function. If weeds (or especially grass) sprout compost should keep the ground soft enough that it makes it easy to pull those weeds. That makes it so much easier. And another main function, to stop weed and grass seeds from sprouting in the first place. I don't see compost laying on top of the soil helping with that unless when you add more you are also killing anything that has sprouted. Or your mulch is sterile and thick enough to help keep sunlight from sprouting seeds.

I don't use compost as a mulch, I use it as a soil additive and dig it into the top few inches of the dirt. It adds nutrients but also helps improve the tilth of any soil.

In Arkansas my typical method of mulching was to spread newspaper (and often cardboard between rows) and put wheat straw or old wood chips on that to hold the newspaper in place so it didn't blow away in the wind. The newspaper did a really good job of suppressing weed and grass seeds from sprouting or, in the case of grass, just coming to the surface through the mulch from its roots. Bermuda grass would still come through some but mulching with newspaper really helped. The mulch on top of the paper insulated the soil to help cool it but softened the bright reflective white you'd get from the newspaper. Newspaper by itself would not work, it would blow away. I guess you could use compost to hold the newspaper in place but to me the compost is more valuable as a soil additive. At the end of the season the newspaper had pretty much rotted and so had most of the straw or wood chips. I'd leave them in place over winter to help keep weeds and especially grass down (I hate Bermuda grass in the garden) which made soil prep much easier in the spring. If the straw or wood chips were not sufficiently rotted to just dig into the soil (a valuable addition) I'd rake them to the side and use them as mulch on my early cool weather crops. Then they were compost.

My typical method for wood chips was to use them the first year in my landscaping beds. I'd either get them from a utility clearing trees or I could get 2 yards from a neighboring city for $10 if I hauled them myself. There was no telling what types of wood or seeds were in it or what chemicals somebody might have used on them. They never harmed my landscaping beds but I figured a year in there took care of any chemical worries I might have using them around stuff I ate. I did get a lot of tree seeds to sprout, but those were easy to pull. And with two years of use about the only wood chips that did not rot down was cedar.

Not well-rotted straw, wood chips, or dried grass trimmings (I sometimes used those too) can tie up nitrogen if just dug into your soil, but I figured by putting them on top of the newspaper I minimized that problem by keeping them out of the soil. I never noticed a lack of nitrogen problem. Having some organic matter helps keep your soil "alive" with certain microbes or such. I think that is a good thing. But I did see a huge benefit in digging in a lot of compost. When I'd empty my chicken coop into the garden in the fall and used that area for my warm weather stuff the next spring I did see a huge benefit. That stuff had time to break down before I planted in it.

I'm sure there is some application where a layer of compost could be used as mulch, maybe sterile mulch to suppress weed seeds from sprouting, but I find it more valuable used other ways.

 

[heirloomgal]

But also it can break up the capillary action that brings water to the surface where it can evaporate. I don't think compost as mulch would help much with that.

This is an excellent point, and part of why I always found the compost as mulch suggestion hard to figure out. It brings to light the question of what the ultimate goal one is trying to achieve with the mulch. That's the sticking point because different mulches can have totally opposite effects, like the black plastic sheeting you mentioned. That effect would be, in some ways, the opposite effect that I create with my straw mulch. The main reason I mulch is to retain moisture and cooler soil temps, and to keep weeds from growing. Then, to enhance my soil.

Straw or wood chips and stuff like that gives some bugs like squash bugs great hiding places.

This is so true, and occasionally in cooler & wetter summers I've had to remove my straw because of excessive moisture and slugs. Like many things its a cost/benefit ratio to be worked out.

I once tried the black sheeting; it wasn't that shiny plastic, but a kind of fabric that was supposed to let water in, but not out, heat the soil and suppress weeds. I covered a lot of area with it, relative to my garden size. It was only one time, so this observation is hardly scientific, but I can honestly say that there were some ill effects to using that material in my garden. I found that plant performance was poorer than usual, less vigorous. I could just tell that something wasn't the same. At first I wondered if it was a toxic runoff, being a form of plastic in hot sun with water running off frequently, but I did a bit of research and I think it was related to aeration. Some say 'the soil can't breathe'. I'm sure lots of people swear by it, and there are a lot of benefits to having something so impenetrable and heating, but I have a not huge garden so I tend to notice even small changes in my plants' production levels. It was a lot of effort putting it in too! Not as easy as my lazy method of throwing some straw around!

 

[AMKuska]

@Ridgerunner This is exactly the sort of information I was looking for. Your comments are detailed enough to help me understand the pros and cons of everything, as well as giving me alternatives to consider. I really appreciate it!

@heirloomgal I want to avoid plastic use in my garden as much as possible. I do want the soil heating action, but I've had really poor luck with plastic sheets in the past also.

 

[ducks4you]

Also, no matter WHAT you produce, or WHAT you call it, vegetative compost/mulch will break down and continue the symbiotic relationships between microbes, tiny soil bugs and worms and growing vegetation, vegetables or flowers or lawn Long After you lay it down on the dirt. I picked up "plastic mulch" that was in tatters at DD's house, who KNOWS who old it Was, but it WAS in tatters and simply became trash to fill the landfill.
THEN, you talk to entomologists who insist that pollinators are dying off bc we use TOO MUCH mulch and they need open lawn.
Enough to drive you crazy.
It's like this, compost your food waste, never meat.
Compost your leaves.
Compost all weeds that have NOT gone to seed.
Compost your cardboard...you must have a LOT of this with all of your online buying during COVID.
Some people even compost old cotton clothes.
If you are patient, you get great garden soil.
Anybody with livestock should know how strong the manure is when fresh, and how long until it is safe to TOUCH your plants.
Also, if you live in a P.U.D. (Planned Unit Development), where the streets were laid out, it was probably an old farm and it wasn't flat. The builders pushed it flat, and while doing so removed whatever topsoil was left after the farmer quit, and left you with...straight clay.
Your lawn doesn't grow well and your garden won't either unless you feed it.
Even My property, 5 acres of what was a working farm until 40 years ago, is full of clay. Now, my horses have put down enough manure to change a lot of it, except where they graze, and I have to fertilize that as much as possible so that they have healthy, summer pasture.
Compost/mulch is a cheap and easy way to put life back into the clay and resurrect it to support plant life.
Weeds are hardy survivors that don't Need fertilizer. This is why they fill in bare spots. Even that helps keep the soil from blowing away, so they serve more good than a landscape with nothing in between your plants, as many gardeners grow.
Miracle Grow and other "instant" fertilizers are short term, chemicals that die after 3 months.
Compost/mulch doesn't die off.
Charles Darwin discovered that earthworms create an inch of soil teeming with microbes, etc./year, from decaying leaves. Nobody seems that remember That book.

The Importance of Earthworms: Darwin’s Last Manuscript

Charles Darwin died 130 years ago today, leaving an intellectual legacy which has profoundly influenced the general course of Western thoug…

www.nypl.org

 

[ducks4you]

A very simple way to grow plants for your compost pile is to grow alfalfa or red clover. Both of these plants can be tucked between rows or planted at the edges of your beds. When the plant gets tall (according to your tastes), just shear it back and toss the clippings in the compost pile; it will continue growing

Keep Your Compost Weed-Free

Weeds can be safely added to a compost pile if you make sure temperatures are high enough to kill the seeds and roots.

www.thespruce.com

Growing In Compost Without Soil: Facts On Planting In Pure Compost

So if compost is so good for your garden, why use soil at all? What's to stop you from growing plants in pure compost? Learn more about the wisdom of vegetable growing in compost without soil in this

www.gardeningknowhow.com

 

[ducks4you]

AS LONG AS YOU DON'T add meat or bones to your compost--eggshells are ok--you can't make a mistake composting. Meat attracts predators that will, at least, dig into it. It attracts vermin, too.
Compost doesn't attract vermin to your property.
Just bear in mind, creating compost is grunt work and it can take years to make it.
Shortcuts are really hard work, like shoveling up your pile EVERY WEEK.
I have grown great heavy feeders, like corn, in last year's compost.
Better than buying it.
There was a recent (last few year's) thread where somebody here bought composted cow manure that had been laced with herbicide.
Dead plants.
I am sparing with D2-4 bc I will poison my horses if I am not careful with it.
Look at the weeds to be sure you are not putting their seeds in your compost or you never see the end of them.
Do the research. I started reading about this in 2009 and it doesn't matter what you call it.
Find somebody's garden that handles waste the way that YOU LIKE IT, and copy that,
Far be it for me to tell you how to compost.
Guess that makes me a "FARB,"

 

[ducks4you]

I DO pull seedless weeds and throw them on my lawn and use my mower to "compost" them. Just sayin...

 

[heirloomgal]

I DO pull seedless weeds and throw them on my lawn and use my mower to "compost" them. Just sayin...

@ducks4you You really seem to know a lot about home composting methods, and one of the last major things to be dealt with in my yard is the giant 'compost' pile (if you could call it that). It began as a place to bring garden material at years end, yard raking, weeds and whatever else organic non-food waste there was. We kept out any large tree limbs and big things like that. My hope had always been that someday I could harvest some soil from it. The majority of my pile today - after 11 years or so - is leaves, twigs, guinea pig bedding, expired garden vegetation, a bit of tree clippings and maybe the odd fall pumpkin. No kitchen wastes because we have mega bears. Every year I go out with a pitchfork and poke around and there is never dirt to be had. If there is, it is so mixed up with woody material I can't actually scoop any of it up. My pile is now rather large about 3-4 ft high and maybe 10 feet across. I would LOVE to be able to convert this pile into usable soil of some kind. Is there any hope????? I wonder if I could saturate the pile with something to encourage things to break down faster? (If a picture would help I can do that, but it won't be pretty!)

 

[AMKuska]

@ducks4you You really seem to know a lot about home composting methods, and one of the last major things to be dealt with in my yard is the giant 'compost' pile (if you could call it that). It began as a place to bring garden material at years end, yard raking, weeds and whatever else organic non-food waste there was. We kept out any large tree limbs and big things like that. My hope had always been that someday I could harvest some soil from it. The majority of my pile today - after 11 years or so - is leaves, twigs, guinea pig bedding, expired garden vegetation, a bit of tree clippings and maybe the odd fall pumpkin. No kitchen wastes because we have mega bears. Every year I go out with a pitchfork and poke around and there is never dirt to be had. If there is, it is so mixed up with woody material I can't actually scoop any of it up. My pile is now rather large about 3-4 ft high and maybe 10 feet across. I would LOVE to be able to convert this pile into usable soil of some kind. Is there any hope????? I wonder if I could saturate the pile with something to encourage things to break down faster? (If a picture would help I can do that, but it won't be pretty!)

@Alasgun told me about his lactobacillus spray and how to make it. It broke my compost down incredibly fast when I dumped what I thought was a failed one into it. Here's the link: https://www.dudegrows.com/soup-lactobacillus-culture/