Mulch options & winter cover crops

I'm curious what mulch options you experts use that would add nitrogen, help break up clumpy soil, and have minimal weed seeds?  I'm looking at two options, but am not sure which way to go.

I've heard grasses like lawn clippings & straw are good for returning nitrogen to the soil, but the spot I'm in now has a large vole & mouse population.  If I use straw, I'll invite rodents, & if I use grass clippings, I'll invite more weed seeds.  I'm currently growing sweet corn, so don't want rodents around.  I'm diligent in keeping down my weeds, but want to retain moisture, add nitrogen, and soften my soil for next year (hard surface crust).

I plan to grow more sweet corn & add watermelons next year (both use a lot of nitrogen).  What are your recommendations for a cheap winter cover crop of legumes or other nitrogen fixing seed that I can simply broadcast & rake in?  

Why not woodchip mulch? This time of year, tree trimming companies will have trucks full of mixed leaves & woodchips they want to get rid of, and tiny tree saplings are much easier to yank once & kill than most other plants.


Mice/Voles like dry straw for nesting material. Soft, insulating stuff to raise their babies in. Once it's wet and starts to rot - if you can keep it wet, the mice should leave it alone. No one likes a rotting nest.
Topping it with mulch can help keep it wet.

To suggest a winter cover, we'll need to know what zone you're in. Will you be able to GROW things overwinter, or will it be something that grows during fall, dies off, and then decomposes overwinter?

Are you tilling?

If you're growing corn, you could also send the corn stalks through a mulcher and use that as a supplemental mulch, to return some of the nutrients back into the soil overwinter.

So far, I will be adding some bark/wood chip mulch from my wood splitting pile, as well as some chopped up dry leaves in the fall.  I did plan on chopping my corn stalks to incorporate as well, but these will all be done by the first frost.

No tiller, but I do manually turn the soil with a shovel in the spring before planting.

I don't really want the bulk of my mulch to be wood chips due to the way I turn the soil with a shovel.  Perhaps I could bury the wood chips in the bottom of the shoveled hole to give them a year of decomposition before they surface again?  I might just try that.

I will not be able to grow a winter cover crop during winter.  I had in mind something that grows during fall, dies off, and then decomposes overwinter adding nitrogen.

I could do straw, and might just work it into my plans.

I know one of my neighbors has a handful of chickens in a coop, maybe I could take the litter/manure off their hands?

I have really good soil now, & I want to keep it improving.  My only complaint is, it develops a hard crust after heavy rain followed by really hot days.  It actually hindered some of my seeds from sprouting through the crust.

Cy, I use straw mulch in my beds, and do not see any major problems with moles or voles.  I like to put my fresh straw in the paths between the rows and let it decompose for awhile, and then take that material and put it around my veggies in the planting beds.  The partially decomposed straw is much easier to place without smothering out young seedlings.  I have also been experimenting with using deep compost 4-6" in my raised beds.  I have been having good luck with this method too.  I am noticing that the weed pressure is much less than when I just sprinkle a little compost over the native soil.  I did have to purchase a dump truck load of compost though, which was $350.  Hope this helps!

Nice looking garden!  I think I will incorporate straw into my plans after all.

For the criteria you listed, it seems that a layered approach would be best. I suspect ideally, adding bloodmeal (or cottonseed meal which is cheaper) with finely chipped woodchips over top would accomplish your goals. By planting time next year, the woodchips should be broken down enough for you to still turn the soil, although this turning actually destroys most of the progress you would make with the amendments/mulch.

Cy Cobb wrote:I have really good soil now, & I want to keep it improving.  My only complaint is, it develops a hard crust after heavy rain followed by really hot days.  It actually hindered some of my seeds from sprouting through the crust.

This is a sign that your soil structure is poor, which could also indicate that a lot of the good critters you want in the soil like worms, beetles, etc. may not be present. A nice persistent mulch, like wood chips or a thick layer of straw or shredded leaves will help retain moisture, preventing the surface from drying out, and will make the environment more welcoming for those critters you want.

I do have tons of soil organisms, lots of worms, & more beetles/grubs than I'd prefer.  I turned the soil in the spring to move the weeds deeper into the earth to decompose rather than pulling them since they covered the entire plot.  This was preferable to me since it only cut a few worms, and kept more accessible nitrogen in the soil as opposed to what a tiller would've done.  This left me with a nice fresh seed bed devoid of weeds to compete with my seedlings, although it did take some busting up of dirt clods to get it finer for seed contact.  This is my first year with this new plot, and before this always tilled garden plots.  I'm discovering these things like the crusted surface as I go.  I will take your advice about the mulch with wood chips, bark, leaves, chicken litter (if I can get it), & straw.  I do need some strength in the soil for my corn to grip during storms, as opposed to a super soft deep mulch, but I think over time, I can build it up with the organic matter to find a happy medium.  

In your layered approach recommendation, is that for building a top soil where there isn't one currently?

IMO,  using grass clippings is way less likely to increase a weed seed issue, especially compared with tilling where seed deposits in the soil are constantly being turned up and exposed to the light.  I use grass clippings heavily and extensively in veggie growing areas and have dramatically fewer weeds each year.

So, growing up, everyone I knew tilled their backyard garden plots with no mulch whatsoever.  We operated under the mantra of "1 year of seed equals 5 years of weeds"; meaning, if you weren't diligent in weeding your garden and let the weeds "go to seed", then you would be weeding those seed sprouts for the next 5 years.  It helped to have child labor to do the weeding of course, lol.  Years later, I met a man with a very successful garden that had a very thick layer of grass clippings covering the entire plot.  He's since passed away, so I can't ask him if he tilled it in every year, or if he just left it to decompose as it touched the soil.  I can see why you'd never have to weed if you blocked the sunlight with a thick enough layer of grass clippings.

Cy,

I will give you my 2 cents and you can take or leave it for whatever you think it is worth.

Firstly, good for not breaking out the tiller.  I think it is a good idea to get away from those for yearly use.  But the same can be said for digging the bed up with a shovel each year.  Not only is it a lot of unnecessary work, but it can actually harm the soil, though not as badly as the tiller.

The wood chips from your wood splitting pile will work very nicely at conditioning the soil.  Don’t bury the wood as it will take ages to decompose when buried (this is different in a hugel mound).

Straw is fantastic mulch and looks very nice, helps suppress weeds, etc. but it won’t add much in the way of nutrients to your soil.

Now if you have them, grass clippings can possibly be your best possible mulch, assuming they are chemical, especially ‘cide, free.  Fresh grass clippings are nice and high in nitrogen and will start amending your soil just by sitting on the surface.

Now some for some unsolicited food for thought, I would suggest that if you really want to increase your soil fertility, concentrate on the soil biology and not worry about the soil chemistry.  Bacteria, fungi and earthworms will all work together to really improve the soil for your plants.  My personal obsession is to use Wine Cap mushrooms to break down wood chips in the garden bed.  The resulting compost is amazingly fertile stuff.

Cy, there has been a lot of very good information on this thread and I largely agree with it.  I add my own suggestions for your consideration and if you think this is helpful, great!  We can talk more.  If you don’t think this will work for you, then do your own thing.

Best of luck!

Eric

Thanks Eric for your 2 cents, much appreciated.  I don't have a bagger for my mower, but I could lay down a large tarp & shoot the grass clippings into it.  My mower mulches the clippings pretty small, so raking is fairly fruitless.  Thanks everyone for your explanations & input.  I need to do some more homework on winecap mushrooms, but for now I'm really into my sweet corn projects & planning for watermelon next year.

Cy,

I usually rake my grass clippings (if I want them) as I don’t have a bagger either.

If you are interested in the Wine Caps, I have a long running thread HERE:

https://permies.com/t/82798/composting/composting-wood-chips-chicken-litter

This documents my journey from being a complete fungal neophyte to having successfully cultivated mushrooms and having a degree of competency today.  I try to keep it updated.

Eric

I'll check out your thread when I get some time, thanks!

Can I add a third (lost count!) option just to muddy the waters in case it helps someone if not the OP. I've been doing a lot of reading and watching Elaine Ingham on the importance of plant root exudates in feeding the soil biota which in turn feed the plants roots. The principle I'm trying to describe is the use of living roots to improve the soil. This thread is about compaction: https://permies.com/t/157995/Breaking-soil-compaction-plants, but there is useful discussion around the principals that I found helpful, plus some good links.
Still getting my head round how it might work myself, but one of the options I've been trying out, and you might like to consider, is tiller Daikon radish: Depending on your climate zone, you sow in early autumn, the plants send down deep taproots and then are killed off by winter cold. This is where your climate zone comes in: my winters are mild so the radish will over winter quite happily and go to seed the following year. That would leave you with organic material through the soil depth plus the top growth on the surface to protect the soil from weather.
The other option, that seems to be a bit more tricky to get the balance right since it involves perennials, is a permanent cover crop of a legume suited to your climate area: alfalfa and white clover are two I've seen mentioned. You then cut it back and seed your vegetables directly into it (or in between rows of it).
I've been experimenting with improving a couple of areas of very compacted soil: very much a long term process (my project thread here). I'd dearly love to get some soil biology tests done but can't justify a powerful microscope at this stage.
Anyway - hope this helps!

You could seed a cover crop and cover the seed bed with mulch. I myself would cover the seeds with  an inch of bulk mushroom compost or very well composted manure. Get the oldest manure in the pile so you don't have to fight the weeds that any uncomposted seeds will bring. Test the manure, before you haul it, for herbicides by mixing some with your garden soil in a container and plant some bean seeds to see if they germinate.

I personally like winter rye as a cover crop as it does not need a mulch.

Winter rye comes up thick so a mulch is not necessary.

When the weather gets to a certain temperature the rye dies back and a spring garden can be planted.

I suggested two options in one. The mulch is one very much needed option for this soil.

Cy I didn't see your climate zone, so here's a recommendation that works in most of the US. Use a rye/clover mix to cover crop your garden. Rye can withstand temperatures down to -30 F. Red clover can withstand -20 F. White clover can also take cold temperatures though I couldn't find any solid numbers. When, spring comes around mow down the rye. I have also had vetch survive the winter, though if left alive it will attempt to climb your plants in summer (though this happened, I don't think it inhibited my tall plants).

Another option or one that can be used in conjunction with (rye/clover) is to spam your garden with brassicas after your last fall harvest. Mustard, cabbage, raddish, siberian kale, and arugula. This can be used in combination with clover or vetch for nitrogen fixation. The radishes will improve soil compaction, brassicas are phosphorus/sulphur accumulators, and this plant group also fumigates your soil  to control harmful fungus and microorganisms. You can eat a few leaves off of these in early winter, or you can feed it to chickens. By December and January they will be frozen dead and you won't have to worry about it come spring.

I'd be careful of using rye as a cover crop if you want to plant in the spring. Rye does not die back in the winter, even a -20C winter. In my experience (I've grown rye every year the last seven years), mowing it in the spring does absolutely nothing. Repeated mowings do nothing. By the time the rye stops growing back, you've missed your planting window for most things.

The advice I've seen for using rye as a cover crop is to till it under in the spring, at least two weeks before planting. You want it to break down a bit and also want the rye's allelopathic properties to dissipate. Those allelopathic properties are part of what makes it such a good cover crop. But I don't think it's a good option for a no till garden you want to plant in the spring.

If you want to go with a grain, go with a less hardy, spring planted variety. I can't recommend any because those varieties don't grow well for me, so I don't have experience with them. They should die off over the winter, though. Oats are usually recommended. Supposedly there's less hardy rye, too, but I've never encountered any.

I like Nancy's idea of tillage radish. I might add peas to that for nitrogen.  White clover is pretty bossy in my gardens. I let some infiltrate one of my beds and am regretting it.  It just spreads too fast and has really dense, tenacious roots. You could also go with buckwheat.

I didn't plant some of my gardens this year and just let the wild pansies/Johnny jump ups take over. Most of them got over a foot tall, and they grew so densely almost nothing else got through. They have shallow roots, so super easy to chop and drop by grabbing handfuls and pulling sideways parallel to the ground and no disturbance to the soil. Lots of biomass if nothing else. Like me, you may have something already growing there that makes a great cover crop.

Cy Cobb wrote:In your layered approach recommendation, is that for building a top soil where there isn't one currently?

It will do that, but it will also help to make existing soil better. I've found that the more consistent moisture and availability of organic material that this provides makes any soil better and produces better plants with less work than if planted in the exact same soil without amendments & mulch.