Living Mulch - no till

I'm weighing all of my options are far as ground cover in a new (ideally no-till)garden plot I am making. I've considered hay, the concern would be slugs, straw, the concern is persistent herbicides and compost, the concern is having a flat viable seedbed for seeds being blown onto the area (strong winds and unkept pasture surrounding plot). I am now looking into living mulches for the pathways and beds, specifically Dutch white clover. Does anyone have any experience with living mulches of any kind? How did it work out for you?

Do you have to kill back the mulch when you plant seeds or seedlings? Is choking out new plants an issue?

What about adding fertility each year?   The clover will fix nitrogen but what about other nutrients. Could/should I lay compost on the plot each year and reseed the clover on top?

thanks,
Jack

Also, how does using clover as a living mulch work into crop rotations since you would always have legumes in all beds?

I am doing no till with straw mulch for annual garden.  I am harvesting my own straw so no pesticide concerns.  I have had no slug problems.  I have violet, white and red clover, dandelion etc in borders.  Which maybe why I have no slug problems.  Following this.

Where are you? We have not many if any slugs here. So hay is our first choice.

Are you talking perennial clover in an annual garden? I would not recommend it. Even in with smaller perennials clover can be quite aggressive.

Ontario, Canada. ZOne 4b.          THe aggresiveness of clover is one of the big advantages as far as I can tell, it will outcompete taller weeds with longer roots. But i do think that part of the situation has to be to cut them back around new plantings to give them a head start. I'm very curious about it all and would love to find someone who uses living mulches to find out the actual logistics of it. Theres a lot of theoretical positives and theoretical negatives. I'm hoping to get to the bottom of it all.

Dutch — I assume you're talking about a similar short perennial — clover is definitely not a replacement for compost, but it is a good addition and IME the best living mulch for annual beds if you can get it to take hold.

Do you have to kill back the mulch when you plant seeds or seedlings?

I just rip up a chunk of the clover where I'm transplanting. Which brings up a point: you will have to transplant (no direct seeding) if you want a living mulch like clover. Often times I transplant right next to the rotting stem of the previous year's plant, so there's already a gap/space.

Is choking out new plants an issue?

Nope. Clover has a pretty shallow root system, combined with it's short height and transplanting hasn't made an issue for me.

A couple of points you may want to consider as well:

* It can be difficult to get Dutch Clover established on bare ground. It may take several years to get anything close to a ground cover. Depends on your soil.

* You'll need to mow or chop the clover in order for it's nitrogen to become available to other plants. Luckily, it responds very well to mowing.

* Because of it's shallow root system, it's not going to be good at accumulating a very diverse set of minerals. Compost, mineral applications, or other accumulator plants are going to be needed for long-term fertility.

My suggestion would be to just try it out. Dutch clover seed is really cheap, and there aren't really any downsides to trying it out. It certainly won't be the end-all for a highly fertile bed (you'll need to start with a soil test for that route), but it won't hurt.

clovers have to be cut back in order to reap the benefits of their nitrogen fixing, this means you will be replanting it every year.

clovers grow rather aggressively, plant some low growing vegetables and they will be what is choked out by the clover.

Living mulch works but it is intended for areas like path ways, since this is where you will gain the covered ground benefit from them.
for pathways I prefer Scottish moss or Irish moss, they make a soft carpet and will stand up to traffic wear and tear.

Clovers for Buzzard's Roost are used for pastures, cuttings for the compost heap, erosion control and pollinator attractants.
Grasses are used for pasture, hay for winter feed, cuttings for the compost heap, erosion control.
Brassicas are used in pasture areas.

Deep rooting vegetables such as Rape, Daikon Radish, Seven top turnip and other similar plants are used for pasture, soil conditioning and loosening, cuttings for compost heap.

You need to understand the plant then put it to the best for you purpose it can fill.  All Nitrogen fixing plants are good at storing N for their own use, not so much making it available for other plants with out the Fixer plant being dead first.

Redhawk

I did white clover and it got so tangled in everything it wasn't fun. Not necessarily choking plants but it was just too much work to get plants out or harvest etc. maybe with larger plants like zucchini or squash but other than that I stick clover with perennials only

I'm wondering more and more if planting cover crops is really necessary at all.  I'm not certain how much advantage there over just letting weeds grow as my cover crops.  When I'm ready to plant, I can mow them down, layer on mulch and make holes or rows to plant in.  Even if weeds don't fix nitrogen, they contain it and will release it to be used after I chop and drop them right?  

Todd Parr wrote:I'm wondering more and more if planting cover crops is really necessary at all.  I'm not certain how much advantage there over just letting weeds grow as my cover crops.  When I'm ready to plant, I can mow them down, layer on mulch and make holes or rows to plant in.  Even if weeds don't fix nitrogen, they contain it and will release it to be used after I chop and drop them right?  

Good point. I totally agree with letting weeds do it's thing. I still use cover crops for more specific soil enhancement but in my experience weeds did not hinder my plants, if anything they were aiding them this season.

Weeds are a cover crop, what is a weed? A weed is a plant growing where we don't really want it to grow.

Some plants are better cover crops than others because of the variety of nutrients they take up from the soil at different root depths.
All plants will do some of this "mining" and bring these items to the surface soil when chopped and dropped as a mulch layer to decay and feed that critical top 8 inches of soil.

The top 8 inches of soil are critical only because that is where seeds germinate and developing root systems get their first charge of nutrients.
There are many plants that utilize this layer or horizon of soil through out their life span, never going below that first horizon of top soil, such as the berry plants.
The deeper we can create the critical top soil the better our plants will grow, the more nutrition they can provide us and the plants will be inherently healthier and able to resist diseases and pests.

the cover crops are more needed when planting heavy feeding crop plants such as corn, a notoriously heavy feeder and why the first people developed the method of planting a fish under the corn seeds.

Redhawk

Like others here, I'm not the biggest fan of clover because it can get a bit invasive and it's hard to remove once it gets established.  

I cover-crop with a wide variety of different seeds -- mostly forbs and legumes.  I sew two crops a year and just hack them back to the ground when I'm ready to plant other veggies.  I buy my seeds from groworganic.com, but there are a lot of other sources for seeds.  And, I'm constantly collecting my own seeds as my cover crops mature.  I'll end up with a 5-gal. bucket half-full of radish, oats, vetch, and other seeds.  When I get my order of seeds in the mail, I'll mix these with the new seeds, and end up having almost 5 gallons of seeds to plant.  It makes for a full day's work.  Make sure you order a bacterial innoculent if you want your legumes to fix nitrogen.

More than that, however, is that once the plants come up, I constantly drop fresh mulch down around the growing plants.  Comfrey, for the baby plants.  But as they get taller, I throw just about anything down in and among the growing plants.  Just this morning, I put down a bunch of spent tomato vines around my pepper plants.  I just pile it up between the rows and around the base of plants.  Not too much compost goes in the compost pile during the summer because all those veggie scraps and plant trimmings just get dropped right back down around the base of other plants.  In this way, your cover crop is your veggies, and they immediately become your mulch as soon as they are done producing.

So if it were up to me, I'd shy away from clover unless its for a pasture or something that you won't be actively working in.  If it's a veggie space, I'd go with shorter-lived cover crop species that you can chop and drop and not worry about becoming invasive.  Buckwheat.  Bell peas.  Vetch.  Oats.  That sort of stuff.

While I hesitate to contradict Bryant, I have found many sources including Toby Hemenway, Mr Wheaton and Dr. Elaine Ingham who have asserted proof that n-fixers do not need to be killed to release nitrogen. Of course killing them will get all the nitrogen they have out of them but it's akin to killing the goose that lays the golden eggs.

On the other hand, when cut back or subject to natural die back above ground due to the season or herbivory, a proportional amount of roots die back and give up that nitrogen to the soil. In addition, nitrogen fixators generally are high in protein, as nitrogen is a proteins main component, and therefore attract animals needing that protein who will trade their nutritionally diverse waste for some clover. Beautiful.

Good catch Ben, You stated that far better than I did. I didn't mean kill the plant on purpose, most of the N fixers will come back from their root system when chopped to the ground, that's the part that dies, not the whole plant.
Thank you Ben for your sharp eyes.

Redhawk

But . . .

(and everyone has a big but)

If you are planting a heavy N fixing cover crop among your row crops or other annuals, there comes a time when they will be competing for sunlight and moisture to a degree that the best thing you can do is chop them and kill them.  I let the cover crop grow side-by-side until my peppers (or beens or okra or whatever) are starting to be crowded by the cover crop.  Then I'll chop and drop them so that the other veggies have room to express themselves and spread out.  Otherwise, the veggies get leggy and tall, trying to outreach the cover crops for the sun.

So you get a number of benefits if you do it that way.

1.  You feed the soil microbial life with the root exudates of your cover crops while they are living.  More roots, more exudates, more soil life, more fertility.
2.  You outcompete weed seeds that want to come up.
3.  You shade the soil between your food crop rows from drying out or being irradiated by the sun.  Bare soil is bad soil.  The cover crop gives shade until your food crop has grown sufficiently.
4.  Once you drop your cover crop, you get that additional boost of N, beyond what would normally sluff-off if you didn't chop them.  I agree with the points made above: yes, N fixing cover crops provide some N even if you don't chop them, but they provide WAY more if you do.
5.  You'll have all that bio mass on the soil surface (from the terminated cover crop) as a mulch, as well as all that biomass below the soil surface (from the roots of your cover crop) to feed the soil food web.

I used to plant my veggie rows much tighter than I do now.  I'd plant them 12 inches apart or so --- smaller for things like beets.  Now, I'll plant row crops like corn, beans, peanuts or okra much wider -- about 2 feet apart.  So there is a lot of space between the rows to plant a diverse cover crop.  For the first 2 months of the growing season, it's a riot of different plants.  I have at least 10 different seeds in my cover crop mix.  It looks more like a jungle than a garden.  But then using a hedge trimmer I'll chop and drop the cover crop, starting first with those cover crop plants that are right up against my row of veggies, but leaving a thin strip of cover still growing in the center of the row.  Then, later, I'll chop and drop that as well.  It leaves a nice thick pad of biomass to walk on between the rows, suppressing weeds and holding moisture.  The veggie crops spread their leaves and fill in that space formerly occupied by the cover crop.

Then, at the end of the growing season, when I cut down the rows of veggie crop, I'll rake the mulch that was formerly laying on the ground between the rows and put it right on top of the veggie stubs I just cut down.  Now I can immediately plant a new crop right down the center of the old row.  I can get 2 or 3 crops a year this way and the soil doesn't get worn out because of the N fixers and the heavy mulch constantly feeding the soil.  

People who don't know what I'm doing look at it and say a couple things.

1.  Initially, they'll say, "Your rows are WAY too far apart.  You're wasting all that space.  You should have a higher density --- you should plant your rows much closer."

2.  Then they'll say, "Those "weeds" (my cover crop) are crowding in on your row of veggies.  You should go in there with a hoe and clean that up."

3.  A few months later, they say, "Doesn't all that mulch on the ground harbor bugs and stuff that eat your garden?  You should get in there and clean all that junk thats laying on the ground between your rows."

4.  Then they eventually say, "You've got such great veggies!  I hardly got any corn this year.  And your okra!  My okra didn't do much at all this season."

5.  Finally, they'll say, "You are so lucky.  You have great soil.  Look how black and crumbly and wonderful your soil is.  My garden is hard clay -- it's tough to grow anything in it because it dries out and is like concrete."  They may live right next door -- there is no difference between what they have from what I started with, but they can't make the connection between the methods I use and the results I've gotten.


You can explain it to some people, but they don't get it.  But they'll come over and pick your excess veggies when you invite them.  After 2 years or so, the light will finally go on for most of them --- oh! -- there is a correlation between the cover crops/chop and dropping, and the rich soil you have in the garden.  

So . . . put me in the camp of those who cover crop, but who terminate the crop for max N fixation as well as biomass production.

Thank you everyone for the thorough answers! I'm very interested in all the techniques metioned. And especially interested in Marco's methods. I forgot to look at which zone you're in (I'll check right after this reply). I'm also going to snoop on past posts to see if you (Marco) have some pictures showing any of what you're describing. I'll have to re-read and see if you mentioned anything about overwintering or how reseeding works the next year.

Thanks a lot,
Jack

Jack, a word of caution/encouragement. Using clover has been a mixed bag for me. It has been an excellent cover crop to decrease the worst weeds, which I define as perennializing plants that are difficult to eradicate. I'm cool with the annual ones that make great biomass and pull out easily.

But... it takes some time. Don't expect to get Marco's soil in a year. I am working with a neighbor who has been doing small-scale production agriculture. This year was his worst ever. Bugs and stunted corn and so on. But, the soil infiltration is improved, the CEC is up, the amount of spiders and ladybugs is startling. He is smart enough to see this heading in the right direction, and is willing to give it another year or two to get actual crop improvement. I think we can get there.

I can tell you the clover is not a panacea, but it is definitely a natural process that we can recapitulate, which in my opinion is the essence of permaculture.

I would include links to my experiments in cloverizing, but I'm on a device that makes it impossible and spelling is alos fun...

Jack Somerville wrote:Thank you everyone for the thorough answers! I'm very interested in all the techniques metioned. And especially interested in Marco's methods. I forgot to look at which zone you're in (I'll check right after this reply). I'm also going to snoop on past posts to see if you (Marco) have some pictures showing any of what you're describing. I'll have to re-read and see if you mentioned anything about overwintering or how reseeding works the next year.

Thanks a lot,
Jack

Hey Jack,

Sorry -- I don't do technology very well, so I don't know how to add pictures.  I can operate a back hoe or a front-end loader and have installed a grey water system, but I don't own a cell phone.  I can describe it a bit for you.  We live in Los Angeles county, hard up against the northern edge of Orange county --- about 10 minutes from Disneyland.  Our home sits on a third of an acre, with almost all the lawn having been converted to growing space.  I've got peanuts growing in the front yard, currently—my dear wife tolerates my quirky ways.  (It all looks lovely from the street).  We can grow three crops a year, as we don't get frost.  I'm able to grow just about everything I want, but low chill varieties, as we only get about 250 chill hours a year.  I push it a bit with trees that are recommended for 400 chill hours, but it's a sub-tropical climate -- not too hot in the summer (due to the proximity to the ocean) and not too cool in the winter.  We get rain from late Nov. to early March -- irrigate the rest of the year.

HEAVY clay soil.  Like pottery clay, heavy.  When it dries, the cracks are at least an inch wide.  So we've mulched with hundreds of of loads of wood chips over the past 17 years, so it's transformed the soil to rich, black and crumbly.  I've got about 60 fruit trees, with most of my garden interspersed throughout.  We cover crop twice a year, fall and then early summer, and (as I wrote above) we chop and drop the summer cover crop as things grow up and need the space.  The back quarter of our lot is a steep hillside that has about 20 trees on it, so that gets a lot of mulch dumped down on it, and then I plant stuff on the top of the hill and let it run down over the mulch -- pumpkins, squash, gourds, etc.  Perennials like artichokes, chaya, moringa, grow on the hillside, with a couple of hundred comfrey plants all over.  The hill is steep and south facing, so I can grow warm season veggies on it in the winter -- it collects a lot of heat.

We run our chickens in a small chicken tractor and turn them loose most evenings for an hour or so before dusk.  They quickly scamper back to their home as night falls, and being that we live so far south, there isn't a long dusk here like you've have up north.  I keep a black soldier fly bin for kitchen scraps, and the girls love to eat the BSF larva.  We have a lot of squirrels and possums coming through to wreak havoc in the garden and fruit trees, so those are easily trapped and turned into BSF food.  As Bill Mollison was fond of saying, the problem is the solution.  We convert those avocado stealing squirrels into eggs.

We capture rainwater, and I'm going to add to that system considerably (much larger tanks) in the future.  We've got a big roof on the house -- we don't capture even 25% of what runs off.  I've built a passive grey water system from the kitchen that waters my apple and orange trees.  I'm planning to do the same on the other side of the house to tap into the water from our shower and bathroom sinks.  Water is about the only external input we have to bring into the system.  I wish I could drill a well -- water gets expensive.

I've messed around with hugelkulture mounds, but in our no-rain climate, it makes more sense to bury wood underground rather than stack it up above ground and pile the soil on top of it.  With a regular re-mulching of wood chips every six months, we don't really need to do hugels, as our percentage of soil organic matter is very high.  Instead, I tend to pile any woody biomass that we cut down (tree trimmings, spent tomato vines . . .) on the downhill side (south side) of the trees on the hillside.  There are about 15 such slash piles on the hillside --- our lizard nursery.  As our trees have grown taller, our space for growing veggies has diminished, but I still find room to plant more than we can eat.  

What compostables that do not go into the black soldier fly bin go into a traveling compost "pen".  It moves around the yard/orchard from place to place, every couple of months.  I'm not an active composter -- I turn it once a quarter, if that.  When I do so, I let the chickens loose and they help me tear about the pile.  Again, we have no reason to compost aggressively when we are constantly adding 10 yards of wood chip mulch every couple of months.  I like to keep a yard of finished compost for my potting mix, but otherwise, I don't use a lot of compost in the garden.  But we mulch like crazy, and with nitrogen fixing cover crops, they feed the soil as well as the growing plants.  Since the primary benefit of compost is the addition of microbes to your garden soil, I don't worry about that so much, as the heavy mulch layer everywhere else is a fantastic medium for building a rich microbial and fungal community throughout the soil.

In the past 10 years, or so, I've become a big proponent of nitrogen fixing cover crops, as I wrote above.  I plant my winter cover crop around the first of November -- the same time I put in my onions and garlic.   Then I chop and drop that in March when I plant our summer veggie crops.  The summer cover crops get sewn between the rows and throughout the food forest in the weeks that follow.  As I wrote above, the summer cover crops are terminated as the other veggies need the space, so not all at once.  I just lay them down around the tomatoes, pepper, corn and the rest of the crops as mulch.  Throughout the year, we generate a great deal of biomass, and combined with the wood chips that we continually dump throughout the whole food forest, it's a bio-intensive growing environment.  We have happy soil microbes.

They say a picture is worth a 1000 words.  I just wrote a 1000 words -- was that worth a picture?

Best of luck as you continue to build your soil and watch your system come to life.

marco - thanks so much for your description. I have been trying to figure out how to use cover crops.   I have access to lot of wood chips, and have been wondering about using them on the annual veg beds - just on top.  It sounds to me like your nitrogren fixing cover crops offset any "nitrogen deficiency", yes? I am trying to figure out how to start - if I put wood chips on the beds first, do I need to wait until they break down a bit before cover crop seeds can germinate?  

Great posts Marco, and I bet a lot of experienced permies would have already have read between the lines Redhawk on your cover crop points, but I was being a nitpick for the newbs.

I have been falling more and more in love with the edible cover crops like favas and brassicas, especially when advising people who need to improve their soil but are understandably anxious to start growing food. Anybody have other edible cover crop favorites?

Wood chips will not tie-up N in your soil unless you till them under.  The only interface between the soil and the chips will be that thin layer right at the surface, but that will not suck N up from the soil or anything like that.  So use them without worry in that regard.  I would argue that as your earthworm population grows exponentially from the worm friendly environment that chips create, their nitrogen rich castings greatly increase the available nitrogen in your soil.  Further, wood chips create a wonderful fungal environment, and fungi also work in symbiotic relationship with plant roots to find nitrogen and other nutrients necessary for plant growth.  

Its nice when the chips have broken down and are threaded through-and-through with fungi.  If you can pile them up and keep them moist for a few months, that's ideal.  But I don't have space for that, so I just put them down generously wherever the mulch layer is thin.  It's crazy how you can put down 8 inches of chips, and it will break down in half a year.  You'll find that chips exponentially increase both bacterial and fungal life in the soil, both of which "eat" the chips.  Fungal dominated soils are better for trees (like they'd enjoy in a forest) whereas bacterial dominated soil is generally better for annuals like veggies (which is why compost is so important).  

How do you plant cover crop seeds when everything is covered with mulch?  Well, it depends.

If the mulch is well broken down, I can seed directly into it.  If you've been mulching with chips for a couple of years, you'll have a harder and harder time discerning where the mulch layer ends and the soil begins.  So if I'm planting in an area where the chips are significantly decomposed, I'll broadcast my cover crop right out over the top and roughly rake them in.  Because the seeds have been innoculated with the correct bacteria to help them fix nitrogen, even if they are growing in more chips than mineral soil, they still seem to do just fine.

If its a newer layer of mulch that is still pretty woody and chunky, I'll rake it back until I find the soil below.  Then I'll sew my cover crop in the soil, and then lightly toss some of those chips back over the top -- maybe an inch at the most -- usually less.  Some things like sudan grass will push up through a heavier layer of mulch, but for other seeds, you don't want to bury them.

On my hillside, I'll rake narrow furrows with a triangular hoe on contour (like mini-swales) and plant my cover crop into those little rows, six inches apart or so.  As they come up, they act as little swales.  If I want to plant back there, I just chop it back.

And often, the mulch is so fresh that I don't do anything for six months.  I'll just leave that area fallow for half a year, watering over the top of the chips at least once a week so they stay moist and continue to break down.  I like that clean look under the trees.  Citrus trees in particular seem to do best with a clean understory.  When I finally get ready to use that space, I'll use a garden fork or rake to pull that mulch layer back.  I bring the chickens over when I do that because there are always so many huge fat worms breakdancing around.  The girls go crazy for them.

Different kinds of mulch decompose at different rates.  If there is a lot of leafy green material in with the mulch when its delivered, it will decompose more quickly.  You can lay it down 12 inches deep, and within 2 months, it will only 6 inches deep or less.

On my primary garden bed, I don't use super fresh chips right off the truck.  I'll take older chips from somewhere else in the garden where they've been breaking down for at least half a year.  After I chop and drop a cover crop between the rows, I'll often dump a small layer over the fallen cover crop.  Using a 5-gallon bucket, it's easy to lightly sprinkle a thin layer of decomposed chips right where you want them.