Which Mulch?

[JackieG]

I am wondering what everyone things is the best mulch for the vegi patch, I have horse poo coming out of my ears ??? .....so I have some of that on there but....
I have used pea straw in the past but I feel there is something better out there for my vegies....pea straw seems so dry and 'big'...

The Learner
Jackie :D

[Veggie Boy]

I'm a bit confused myself about mulching since seeing Burke's Backyard tonight. Burke reckons that most mulches that break down damage the soil, making it water repelant. I'm a fan of sugar cane mulch and haven't had any problems with it to date????I have found that the trick with mulch is to make sure your watering system is under, not on top of it.

[gardenlen]

lol good ol'e burkee does it again, mustn't be any money to be made out of mulch.

ok better late than never but i did just join.

i use lucerne or padick slashed grass mulches in my vege beds, great stuff at present i ahve heaps of my own resource so we are slashing and raking that for all our mulching. we have used sugar cane mulch seems to do same job as the others was better when it came mixed with cow manure and urine, but to remember sugar cane can have a lot of chemical applications during it's growing cycle.

len

[makehumusnotwar]

apparently don burke also said that mushroom compost aint that good. it's a good thing no one told my plants that cos they're thriving and loving it (mine is chemical free). i'd probably take note of his comments, and then search out several other opinions as well. there are pros and cons to just about everything, you just need to be aware of them and then decide which suits you and your purpose.

as far as mulch goes, like len i use lucerne. haven't got any growing (yet) and so buy-in organic stuff. it does get very expensive so i'm trying to grow as much mulch or cut-n-drop material as possible.
things i use - lemongrass - vetiver grass - arrowroot - pigeon pea - molasses grass.

[gardenlen]

looks like he can't make money out of mushroom compost either, without that stuff i probably wouldn't have any gardens going yet, i get mine direct from the farm, can't be overly concerned with chemical residues as without it we'd have no veges, also use it in the composting toilet from time to time.

len :wink:

Hey dudes, leave my mate, Burkey alone. He's pretty cool compared with most of his ilk. He has had the balls to speak out against such things as Australia's ineffective recycling system, 'nothing but native plants' purists, and other politically incorrect and unpopular observations. He has given sustainable lifestyles, passive solar designs, permaculture etc. many good plugs in the media over the years. I am sure he has to pay his bills like the rest of us.

Being out of the country, I have not seen the episode that you are all referring to. But what I think you will find that he is alluding to is that just using mulch is not enough to bring soil to life. Without the bacteria, fungi and other soil biota to break it down properly, most mulches can become detrimental.

If your mulch is working it is probalby because you already have healthy soil. Many backyards etc though have been virtually sterilized through overuse of chemicals, leached toxins etc. Add mulch to these soils and it will sit there, saying "Duh! What now??" Without water, it may dry out to a water repellant layer. Too much water and it may go anerobic becoming an unhealthy smelly mess.

You may need to inoculate your mulch and soil with some friendly soil microbes first. One way to do this is to put some of your mulch into an open container of water and let it soak for a while. It will quickly ferment into a compost tea with wild bacteria etc. Keep it aerobic though or it will get nasty. Water this into the soil along with the mulch.

A better way is to use Gil Carandang's technique for cultivating beneficial indigenous microorganisms from an established ecosystem such as a mature forest.

Unfortunately, many permies forget that the ecosystems below ground are just, if not more, complex than above ground ecosystems. People often think of soil as just another kind of hydroponic growth medium. It ain't so

hooroo

nah, there's nothin wrong with don. we can't knock some guy who's into gardening - there's plenty of other people much more deserving.
like the previous post said - there's so much more to things than is usually presented.
also like the last post - too many people ignore or spend too little time on their soil. soil quality is of the utmost importance! bugger yer veggies, grow some soil first! once you've contributed sufficiently to building and then maintaining the quality of the soil (nutrients/bacteria/pH etc), EVERYTHING works so much better. nature looks after all the details.

Has anyone actually personally encountered a soil so devoid of life that it had a problem incorporating a mulch? Really? Where?
Burkes Backyard is crap, by the way!

[gardenlen]

g'day richard,

don't know if what we had here 3 years ago when we moved on site fits your bill? but very sandy loam devoid of earth worms or any apparent organic matter, it wouldn't hold moisture the sub surface soil was very dry. things are looking better now we introduced mushroom compost, cow yard manure and composting worms, the soil still shows signs of trace element deficiencies but improving. the rate of tree growth alone now is far and beyond what it was then, most changes attributed to mulch and heaps of it. also finding lots more worms on site.

just as an aside we are working a pile of stored slashed grass/hay mulch that has been piled up for about a month 12 foot long app 4 foot wide and would have been about 4 foot high but has shrunk down about 1/3 the height and on level ground, we are finding that the mulch pile is wet/moist in the middle and the ground is also wet/moist, we haven't had a lot of rain in that time app' 24mm and we didn't water it.

len

Actually Len, that sounds like a great example of how mulch will rejuvenate even the poorest soil. Good on ya mate!

[Chook Nut]

G'day all,

No wisdom to impart here.... will just mention what i do at my place and what i have found happens with my technique.

I cut my grass in the paddocks and add them around the trees first... as it means i dont have to mow around them any more! It has the added bonus of smothering out the many weeds that exist... the only weeds getting through are the asparagus fern (no wonder they've finally banned it!) and i just hand pull them out.

I have found that the new grass that shoots from the mulch is quickly gulped up by my chooks; and that it has encouraged a lot of microbial activity to the top of my soil. So i guess what i am doing is obviously beneficial so i will keep on doing it.

Cheers... Dave

[gardenlen]

thanks richard,

it's that simple hey dave, too easy.

and you also spelt paddocks correctly must be something wrong with my keyboard i reckon lol

len :wink:

Hi Richard,

I think you have the bull by the pizzle there, Mr C. You are right, there are very few soils which are completely devoid of life. It is more about having the right kind of life. Unhealthy soils have a much higher load of pathogen organisms, and by association, often lead to diseased unhealthy plants. A soil can be teeming with life, yet not have the right kind of microorganisms to facilitate effective incorporation of mulch.

It is also a question of why the mulch is being added in the first place. Keeping in mind that mulch and compost are quite different. Not all mulch is intended to be incorporated into the soil. With projects in some of our arid (desert) communities, small stones have been used as mulch. Some applications of mulch are mainly intended to assist in water conservation and weed suppression. Others may act as a heat barrier. The stone mulch mentioned earlier also as acts as a dew collector. Early morning moisture condenses on the stones and runs down underneath and into the soil.

Other mulches are intended to eventually become incorporated into soil layers and add to soil nutrition. Apart from the CN ratio debate on which mulch to use, different mulches add different ranges of minerals and micronutrients to soil. The mulch can also modify the pH of the soil. One really needs to know something of what is already in the soil and the needs of the desired plants in order to choose which mulch to use.

Mulches can contain other surprises. Sometimes this can be a negative. For example, secondhand stable straw, particularly from racing horse stables, can sometimes carry very high levels of undesirable additives, depending on what medication regime the horses happen to be on.

Sawdust from chemically treated wood is another example. Some plants are good at removing heavy metals and other toxins from soil. Depending on the species, these tend to accumulate in the leaf matter. Using this leaf matter as mulch would send these accumulants straight back into the soil.

Different mulches require different types of soil biota to effectively breakdown. Mulches high in cellular lignin such as pine needles and eucalypt leaves need certain biota to facilitate breakdown. To be more specific, more fungal biota rather than bacterial are required. If these are not present, these mulches can sit there for years.

This works in the opposite direction as well. Different soil biota feed on different food sources. So the type of mulch used may cause a shift in the relative populations of specific soil biota. Thus possibly causing a rise in undesirable pathogenic species. It is all interconnected, depending on which plant types you want growing above the ground and what beneficial organisms you need below ground.

Poor understanding of mulches and their uses can often be very deleterious to a garden. Another example. High lignin mulches can suck out massive amounts of nitrogen from a soil. (again, not the mulch itself, but the soil biota which is attacking it.) A common newby mistake is using fresh sawdust as mulch. Pine bark chips were the landscaping fad a few years ago. Great for keeping pathways clear. But many a garden were killed by using them around plant stems.

There are few shortcuts to knowledge and experience, Mr C. To garden and farm effectively, people need a deeper understanding of biology, geology, hydrology etc than just herb spirals and chicken tractors. They also need to get dirty.

I applaud the use of mulches. In most cases, the ecology of an area will find some way of making use of whatever is thrown at it. But if you really want to be able to meaningfully shift the balance towards your desired goals in gardening and farming, you gotta start to listen to the earth. Smell it, taste it, learn its language.

Despite their bad press, many Australian farmers and growers are some of the best in the world at doing just that. The problems have often come about because as with many traditional communities around the world, they have been conditioned not to listen to their own intuition and instincts. Rather to trust the men in white lab coats and the company sales reps.

Permaculture, agroecology, natural farming etc are largely about giving people the confidence to trust themselves to create their own relationship with the earth. Along with enough science to facilitate their own understanding of what is happening around them.

Thanks for the input anyway, Mr C.

Hoo roo

p.s. anything and anyone can seem like crap. It is just a question of perspective and what you most need to see to validate your own sense of being.

I should look up my forum password one of these days and log on properly. Ahh, life is so short........

Jemes,
You make some good and instructive points about the various short term effects that different types of mulch will have on different types of soil. However, I am very much of the unscientific approach that any old mulch is good in the long run, especially if you don't overdo any one particular kind of mulch at one time and exercise a modicum of common sense regarding c/n. Just as a compost heap wants to made of a variety of materials, obviously a garden needs to be mulched with a variety of materials to avoid imbalances.
Having said that, any old mulch in any quanitities will eventually result in an improvement, once the soil biota has a chance to stabilise and find its own balance. Lack of mulch is the soils worst enemy.

I have to agree with Richard - any mulch is a good mulch. Here I have used manure topped with pea/lucerne/barley/wheat straw, lake weed, chipped trees (courtesy of the council who were removing trees from beneath power lines), gravel and grape stuff (from wine-making). All of it had good and bad points, but I like the free stuff the best because it's free... All have improved not necessarily the soil, but the plant survival rate, and reduced the watering rate, which is all good.

Rob

Here in the Rio Grande valley there is an introduced tree called the Salt Cedar or Tamarisk. It looks somewhat similar to a Casuarina for you antipodean readers. I think it is originally from Asia, somewhere. It was introduced I think as an erosion control species some time ago. It has since "taken over" in a pretty big way, and the people here now hate it. They accuse it of stealing all the water out of the river and the water table. Some public money became available for its removal and in the last year there has been a failry massive eradication programme carried out. They come in and chop it all down and then chip up all the top growth, before applying poison to the stumps. Anyway, when I had access to a truck I collected quite a few loads of the stuff for use as mulch. Not a few people warned me that it would be very high in salt and so would salinise the soil I put it on.
I was thinking about what Jemes said as I drove past a big pile of these salt cedar woodchips today. I must confess that I don't really understand the science of how plants accumulate salts and how this might be released into soils when their woodchips and leaves are returned to the soil. Seems to me like any negative effects of high salt content would be cancelled out by the water retention benefits afforded by the mulch. But perhaps I am wrong? Aren't salt tolerant species such as saltbush often used in reafforestation in drylands? Any comments?

Hi Richard,

I have a Tamarisk tree(its massive) in my front garden. From my research on the tree when i first found out what it was it seems to be a native to Australia, moreso from the Northern Territory, and they consider it to be a bit of a bother there too. It may just be ppls attitudes to it that gives it a bad name, farmers dont seem to like a lot of trees along the creeks and rivers!

In Australia, Saltbush is used widely in marginal and land affected by salinisation. There is a heck of a lot of research going into its benefits in regeneration of this kind of land. So far, the benefits are showing that it is reducing the water table, which brings up the salt, and is allowing grains to be grown in rows between it to try to improve the land again. Sheep use the Saltbush as fodder.

Rather than ranting, thought i would quickly share a little of what i know, you will find more stuff on the net. Maybe do a search using (.au) to get info from Australia. I would have thought that the Tamarisk would have
helped push down the water table, perhaps it has an alleopathic effect, but i have fruit trees around mine and they dont seem to be effected at all.

Hope this helps a little.

Dave

Three species of tamarix, all commonly called salt cedar (see why we have latin names!) are from China. All very salt tolerant, main use is for hedges or wind barriers in coastal areas. All listed with the US and Australian govt weed authorities but I can't say how much of a concern they are. Sorry I can't tell you what happens to the salt if you mulch them.

[Snake]

I have found the soil here in Meekatharra (middle of WA) to be fairly challenging. The harsh climate of very hot summers and not much rain throughout the year (average 235 mm/year) presents a problem for most organisms trying to eke a living out of the soil, including me (well, veggies, if not a living!), unless of course you are in the mining game. Since our arrival here last October, I have started to add organic material as much as possible, and mulch with whatever comes to hand. As the pH of the soil in my veggie patch was 9.0 to start with, it seems an uphill battle, but the onset of cooler weather in Mar-Apr has at least allowed whatever plants survived the summer to kick on, and we have harvested some good zucchini and eggplant and more recently, tomatoes. Initially I used a native grass cut down from the garden for mulch, which broke down and disappeared pretty quickly, then what little actually grew out my first green manure crop. After that I resorted to fresh cut lawn clippings (it's not much of a lawn, I can assure you - but green around the house is better than red dust!); this was a mistake, as it didn't break down, and instead formed a water resistant crust. :cry:
As for soil biota, there seems to be very little and this is my biggest concern as it makes composting and mulching very difficult and slow. I put most of the herbaceous weeds from the garden into a bin and make weed tea out of it, which the rest of the plants love, and as it smells something like worm castings I'm hoping it is adding something to the soil, but I would guess that any biota that function in the aquatic environment of the weed tea, may not function so well in soil. :?: I am unsure of the best way to introduce such biota other than the continued application of organic matter - any ideas? I am trying to get a permaculture garden going at the school using Ms Woodrow's (classic?!) mandala set-up: a 15m diam circle of hay bales which we have progressively been filling with manure and hay from the animals in the school farm (mainly horses) and whatever grass clippings etc I can scrounge. This mixture appears to be breaking down reasonably well, unfortunately someone let the chooks/turkeys/geese into the garden and they ate all of the seedlings that the kids had just planted out, so it's potential remains to be seen. Anyway, gardening here is as much a trial and error process as it is anywhere else, I guess, so we'll wait and see what happens! Any advice would be welcomed, however. :)
By the way, thanks Jemes for that informative contribution on mulches and soils - I am slowly realising that I have to accept there are no overnight solutions so should be spending my time learning about such things while the garden does its thing.

Cheers!

Mark

Hi Mark,

I have emailed some ideas for you re soil biota. Good luck with the mandala. Don't forget to layer in some of your local soil as you add your manure and hay. Gives you bulk and helps add whatever soil biota you already have to the mix.

Given the drier conditions there, scatter the occasional sheets of 'West Australian' into the mix as well. Avoid newspaper layers which are too thick as these take a lot of moisture to break down.(I once constructed a tropical garden in Darwin that chewed up an estimated 10,000 copies of the NT News. We started with about 5 cm of soil and in two years ended up with over a metre of rich organic soil.) Every now and then, perhaps a few handfuls of fire ash into the mix. And ofcourse once you start to get some soil happening, a few handfuls of your worm castings.

When you are looking for weeds for your weed tea, favour the ones which are harder to pull out. These are generally ones which have deeper roots going down to seek moisture and nutrients. They should have greater nutritional value for your 'tea'.

good luck

hey snake,
we have had some pretty good success with the grass clippings in meeka...as u say, some green is better than red dirt and ours is watered with the retic system. we have composted the grass in a big heap, added some kitchen scraps, some fire ash, and a small amount of dynamic lifter and blood and bone (woolies isnt cheap...) occasionally watered it and it has turned into pretty fantastic smelling soil/compost. its only living life forms that we can find are small bugs (grey, lots of legs, hard shell) and they love the sticks and wood and grass (most the sticks are now hollow). i have no idea what they are but they seem to work well and all the kitchen scraps have disappeared (some were whole onions and sweet potato gone to the pot after 2 days.....).

anyways, home a lot now as have finished work and awaiting the baby so keen to catch up and pick your brain.

cheers trish

[Mont]

Your grey bugs sound like slaters to me Trish, there's heaps in our compost too.

[jimmys]

I would have to say lucerne is my favourite, although I use all sorts of things (here in India, the leftover from sugar cane juicing and paddy straw when available). Lucerne is great in that it has quite a high nitrogen content so that it is not 'stealing' a great amount of nitrogen from the soil whilst decomposing. My family has a farm (in northern Victoria) and as such access to about 20 acres of lucerne which is baled into big round bales. The fact that it is not compressed too much in this format allows good air and water access to the soil as a mulch as well as making it very difficult for snails to cover the very rough terrain.

Thank you Darren for expressing this better than perhaps I did earlier. My point was not to berate others for their own chosen methods of applying compost and other soil additives. My apologies if that seemed to some to be the case. Rather that to point out that if you sincerely wish to realise the potential of a particular area and make the most of your own experiences, you need to seek to understand what is happening when you take a particular action.

One of the weaknesses that permaculture instruction has had in the past has been the inadequacy of background understanding of natural processes. It focused, quite rightly, upon the design elements which permaculture does so well. However successful application of design requires a greater level of understanding beyond that which is usually presented in most courses.

Successful permies have generally acquired this understanding through many years of (sometimes unnecessaryly difficult) trial and error. One should not underestimate the value of more traditional streams of agricultural/horticultural training. They also have their place despite apparent deficiences in ethical and environmental appreciations. The growing field of agro-ecology is seeking to bridge these gaps between existing streams of knowledge by promoting a synthesis of application. (See University of Sydney's Orange based agro-ecology courses.)


Darren Doherty's observations:

"After doing a few hundred tests thru APAL and their USA predecessors over the years its patently clear that if you just put things on without testing you are taking potentially expensive and damaging risks. Stories abound of people (some very well known) following de rigueur advice without analysis and then enduring long term mineral imbalance related issues. As David Smith put it in his tome "Natural Gain" - you have to want to know!

.............Similarly continually applying compost and other organic matter can cause chemical imbalances in soils. A simple test saves waste and future bother." (ref: permaculture-oceania digest, Vol 1 #740)

My earlier comments:

"There are few shortcuts to knowledge and experience. To garden and farm effectively, people need a deeper understanding of biology, geology, hydrology etc than just herb spirals and chicken tractors. They also need to get dirty.

In most cases, the ecology of an area will find some way of making use of whatever is thrown at it. But if you really want to be able to meaningfully shift the balance towards your desired goals in gardening and farming, you gotta start to listen to the earth. Smell it, taste it, learn its language.

Permaculture, agroecology, natural farming etc are largely about giving people the confidence to trust themselves to create their own relationship with the earth. Along with enough science to facilitate their own understanding of what is happening around them."

Jemes, my apologies if I seemed to dismiss your earlier comments with a carte blanche, "she''ll be right" approach claiming that any mulch is good mulch.

But, for those of us that haven't endured tertiary training in plant and soil sciences, could you give us some more specific examples of types of soils and mulches that can have longterm problems?
I couldn't find the posting by Darren Doherty that you quoted so it was hard to place in context. I seem to remember a discussion about rock dust where he warned about overuse, or inappropriate use - but that would be a separate issue to mulch, wouldn't it?

Earlier, you wrote;
"Poor understanding of mulches and their uses can often be very deleterious to a garden. Another example. High lignin mulches can suck out massive amounts of nitrogen from a soil. (again, not the mulch itself, but the soil biota which is attacking it.) A common newby mistake is using fresh sawdust as mulch. Pine bark chips were the landscaping fad a few years ago. Great for keeping pathways clear. But many a garden were killed by using them around plant stems."

Now, I guess that is a good example of a mulch used inappropriately. The high lignin mulch is good pathway material for a few years and can then be shovelled onto the beds, but in the meantime would consume too much nitrogen if used as a garden mulch. But, even if you did make that mistake, and killed a few plants, in a year or two, that woody material would be broken down and would be building soil, right?

Obviously there are some nuances to be aware of in the art and science of mulching, but surely you are better to err on the side of too much mulch (even of the wrong kind) than not enough??? I guess I am going on and on about this point because I am slightly concerned that your warnings will put new gardeners off from using lots and lots of mulch, for fear that they will be making some terrible soil ruining mistake, which frankly, from my experience and with my lack of formal education, seems unlikely.

Finally, just to contradict something I said earlier, this year we grew some wonderful eggplants and pumpkins and a variety of herbs, flowers and weeds in a bed covered 6 inches deep in partly very woody City green waste compost. The soil underneath the mulch to begin with was very poor sand that had trouble growing anything much except weeds, so if the decomposing mulch was stealing nitrogen there shouldn't have been very much at all for the plants, and yet they thrived...
(I want to understand your point of view Jemes, but my experiences tell me something different, or maybe I am just missing your point.)