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Author Topic: To Mulch or Not to Mulch (Fruit Trees)  (Read 2775 times)

MangoCountry

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #25 on: April 13, 2019, 03:02:48 AM »
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« Last Edit: April 13, 2019, 03:04:52 AM by MangoCountry »

Cookie Monster

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #26 on: April 13, 2019, 10:47:27 AM »
How long does it take for mulch to decompose there?

How far inland are you? Coastal San Diego was a dream when I was out there, except for the occasional Santa Ana winds that would kick the temps up 15 - 20 degrees with 0* humidity (which was nice 'cause the night time temps would get up into the 70's for a change).

I lived in Ventura County for 30 years (mostly Santa Paula), fled to Florida when housing prices started to go nuts. 12 years later, I still miss the climate. With the humidity here, I think our heat index is probably around 110* -- but for like 5 straight months without a single day of reprieve.

Yah, you spoiled southern californians don't have the psycho heat, humidity, and rain that we have here. That load of mulch would be fully decomposed in 12 to 18 months here. After 12 years of doing that, you get a layer of muck.

The very first layer of mulch takes a bit longer (24+ months here). But once the first layer decomposes and the soil builds up bacteria / fungi, the next layer decomposes a lot quicker.

If you feed it nitrogen, it's even quicker.

I don't end up with muck after it breaks down either like cookie mentioned.  Below the mulch and above the original soil is about an inch or so layer of soft fluffy black stuff that looks like worm castings.  Its not mucky at all.

I will take some of that humidity off your hands.  When its 115 and 0% RH out and strong wind it makes gardening a challenge.
Jeff  :-)

spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #27 on: April 13, 2019, 11:20:54 AM »
The mulch lasts a year or 2.  It goes faster on the trees that get more water like avocados.

Its 16 miles inland and 1200ft elevation here.  Its a lot hotter here than near the beach.  The weather is pretty spectacular down in the beach towns and downtown san diego.
Brad Spaugh

roblack

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #28 on: April 13, 2019, 12:15:32 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.

WaterFowler

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #29 on: April 13, 2019, 01:18:43 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.

I have heard the same thing happen to others. Begs the question if there were herbicides or other harmful chemicals in the "mulch".

I only get hardwood mulch from the tree companies. If it's landscapers, the mulch probably has lots of grass and weeds in it, and much more likely to have chemicals in it, in addition to tons of weed seeds.

shinzo

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #30 on: April 13, 2019, 01:43:57 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.
And a picture if possible of the tree with the mulch.

spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #31 on: April 13, 2019, 02:21:13 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.

I have heard the same thing happen to others. Begs the question if there were herbicides or other harmful chemicals in the "mulch".

I only get hardwood mulch from the tree companies. If it's landscapers, the mulch probably has lots of grass and weeds in it, and much more likely to have chemicals in it, in addition to tons of weed seeds.

Is there something specific you like about hard wood vs softwood?  My tree trimmer guy will being whatever I ask for.  Ive been getting pine lately. 
Brad Spaugh

sahai1

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #32 on: April 13, 2019, 02:30:11 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.

Fresh mulch can reach 180 degrees F while breaking down, at which point it will catch fire.  What soil temperature would kill an avocado tree?  120-130?   If you take wood chips and compost them, you still have wood chips 2 months later, just much less, but much safer.  Or if you do want to apply fresh mulch, make a high donut ring far from the main stem, the larger the tree the farther away you go.  Make it high and as thin as possible.

Everybody's mulch is different, and your trees likely can build up a tolerance to mulching, eventually your trees can handle a huge mound of mulch around them, but don't go from zero to that much immediately.



starch

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #33 on: April 13, 2019, 02:36:50 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.

Fresh mulch can reach 180 degrees F while breaking down, at which point it will catch fire.  What soil temperature would kill an avocado tree?  120-130?   If you take wood chips and compost them, you still have wood chips 2 months later, just much less, but much safer.  Or if you do want to apply fresh mulch, make a high donut ring far from the main stem, the larger the tree the farther away you go.  Make it high and as thin as possible.

Everybody's mulch is different, and your trees likely can build up a tolerance to mulching, eventually your trees can handle a huge mound of mulch around them, but don't go from zero to that much immediately.

This is a very good point. We would get wood chip piles from fresh tree trimmings (particularly if there are a lot of leaves too) that are giving off sensible heat even several inches away. If you spread this on top of existing mulch (which is insulating) and the layer is not too thick the tree will likely be fine. But if you put a thick layer of fresh tree trimmings on top of tree roots that had no mulch to begin with and that tree has a lot of surface-feeder roots (like avocados) the ground and surface roots will quickly get to tree-threatening temperatures.
- Mark

pineislander

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #34 on: April 13, 2019, 07:33:50 PM »
I'll add a few points of fact, opinion and some documentation. Like wine and many things mulch gets better over time. I started using mulch in the early 1980s and all I had was guinea grass, a tall panicum found all over the tropics. During the 90's I farmed in Arkansas and found a derelict sawmill site which had a 20 year old mountain of sawdust/bark which had almost turned to something like chocolate cake. I worked on that for years till somebody playing around set the newer stuff on fire and it burned down deep underground.
So most recently 1-1/2 years ago I managed to get 2000 cubic yards of Hurricane Irma debris delivered. here is a video showing it:
https://www.youtube.com/watch?v=XnaLWHgib5A

There is a big difference between mulches, usually folks speak of carbon/nitrogen ratio comparing grasses, vegetable matter, leaves and wood chips but really it comes down to the amount of carbon it contains. No organic matter except charcoal contains more carbon per volume than wood.

So far I've covered about 2 acres with it at the rate of about 1000 yards/acre. The decomposition in that time is close to 75% such that one foot turns into 3-4 inches. What I really want to show is how that happens so today I took a few pictures. In my case, in southwest Florida with 50 inches rain per year mostly in the summer and a very poor sandy soil with low organic matter the best agent of decompostion are millipedes both the long and short pill-bugs but mostly the former. These arthropods are primary decomposers of woody material worldwide but especially in tropical conditions where earthworms seem a little soft and maybe vulnerable the arthropods dominate.

Here are photos of the mulch pile once about 10 feet tall in the video above and after 1-1/2 years now about 5 feet. The millipede shown is one of thousands, millions or hundreds of millions across the property which have turned a foot of the mulch into 3-4 inches of feces technically called 'frass'.


Close-up showing the black granular frass.


These guys work day and night for me, all they want is food.

Usually the most rich ecosystems form at the interface edges between radically different systems. Examples would be estuaries where fresh meets salt water, field edges, stream edges, rocks and structures in water. All of these particular edges serve as habitats for species which can co-exist in either system but find the edge to be the best. Hunters and fishermen know this and it's true on the micro as well and the macro level.

When you put mulch on soil you create a brand new ecosystem directly at the interface of soil and air. It is cool enough, dark enough and moist enough for organisms dwelling both in and outside the soil to coexist. It is where fungi can send out their fruiting bodies called mushrooms and breed.
 
Here are some photos of what you can see happening at the surface of well mulched soil:
millipede working on dead banana leaves:

Millipede working on fallen avocado fruitlets:

Mushrooms on mulched seedling Pitomba tree on top of decomposing papaya tree trunks:

Mango tree prunings skeletonized by millipedes:

Mushrooms on logs which have been covered by mulch under avocado tree dripline:


So when millipedes eat the mulch they are consuming lignins and cellulose but derive most benefit from the bacteria and fungi already on that material. They are being predators on the primary micro-saprophytes which are already there. Within the millipede gut there is a population of lignin-digesting microorganisms which further digest the matter and thus as it is expelled as frass the material contains innoculum of bacteri, fungi and higher order creatures.

The frass has actually entered national commerce from south Florida, with the trade name "milli-poo". The sale price is $60 USD per cubic foot with the intended use as an ingredient in compost tea. An acre 3 inches deep with frass is 10,000 cubic feet so I'm almost a millionaire.
https://www.boogiebrew.net/millipoo/

Yes there's probably some hype there  but they did get the stuff analyzed and found it highly enriched in fungal and less in bacteria.
https://drive.google.com/file/d/1Kpnx1WsGFi0gzmNbA17LTPGcQv3FkP_g/view
https://drive.google.com/file/d/1dFDltJXoZXDi6x7bZ1MmJEF1b2DniQUU/view?usp=sharing

If you like journal papers this one took dried leaves in vitro with millipedes and found they do a good job generating nitrogen and calcium and can modify soil ph.
https://www.fs.fed.us/global/iitf/pubs/bc_iitf_2012_Gonzalez001.pdf

Last night we hit the lottery. A 1/4 inch rain fell across our 2 acres, it equalled 13,000 gallons of milli-poo tea!

johnb51

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #35 on: April 13, 2019, 10:19:17 PM »
Good information, pineislander.  I never knew the why and the how of those little critters.
John

FruitFreak

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #36 on: April 13, 2019, 11:11:13 PM »
We have imported tens of thousands of cubic yds of mulch over the past couple years.  Cookie has some great information regarding the affects of mulching heavily long term.  One thing I've learned about growing (even life for that matter) is that you have to do the best you can with what you've got.  You will find varying opinions on how to grow fruit trees or how to manage a farm but everybody's land, financial situation, resource constraints, and priorities are uniquely different.  As others have previously mentioned there are tradeoffs when incorporating mulch into your program.  For us the benefit of heavy mulching in the early years out weighted  some of the disadvantages.  Weed suppression and increasing CEC were our primary objectives.  I look forward to the next soil analysis after two full years of mulching heavily.
- Marley

roblack

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #37 on: April 14, 2019, 09:15:09 AM »
Update on neighbor's avocado. She said the tree was trimmed, and trimmings from the tree were used to mulch. Tree was dead within a week. Sounds like combo of stress from trimming combined with over-mulching/choking the tree out.

WaterFowler

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #38 on: April 14, 2019, 12:10:47 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.

I have heard the same thing happen to others. Begs the question if there were herbicides or other harmful chemicals in the "mulch".

I only get hardwood mulch from the tree companies. If it's landscapers, the mulch probably has lots of grass and weeds in it, and much more likely to have chemicals in it, in addition to tons of weed seeds.

Is there something specific you like about hard wood vs softwood?  My tree trimmer guy will being whatever I ask for.  Ive been getting pine lately.

I dont know why I said hardwood. I meant like hard wood chip mulch from trees. Not soft grass clippings, weeds, palm or brush landscaping mulch.


pineislander

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #39 on: April 14, 2019, 01:39:06 PM »
Update on neighbor's avocado. She said the tree was trimmed, and trimmings from the tree were used to mulch. Tree was dead within a week. Sounds like combo of stress from trimming combined with over-mulching/choking the tree out.
I actually doubt pruning the tree would produce so much mulch to damage the tree. I just did that to a tree and had no ill effects, and have done it before. Last year I pruned, laid wood logs side by side to cover the 10 ft wide bed and mulched over the logs till the logs could not be seen and fertilized with compost, biochar and slow release fertilizer all at the same time, then installed sprinkler irrigation. The result was strong growth and a complete rebuilding of the canopy of some severely stunted avocado trees. This was on a 100 ft long bed of avocado trees about 20 trees total. It was done last July during the rainy seson. They flowered and set lots of fruit this year and have held fruit to 1" size so far it looks like the row is now in full production for the season. I have also interplanted a dozen papaya trees and two Sabara Jaboticaba, several Monstera, many Jack bean and pigeon pea support plants in the same bed. All are growing fine so I think that mulching avocado is the absolute best thing you could do. They are known to have a superficial surface feeder root system which will only benefit from mulch. The biggest fault avocado has is a susceptibility to root and trunk rot from standing water. Please have a look at the amount of mulch being used in avocado in Australia and all the cautions but note the mounds they are planted on.
https://www.youtube.com/watch?v=fYYZuNjnvbk

Similar results in California:
https://www.youtube.com/watch?v=fBMvGhHuXxU

jtnguyen333

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #40 on: April 14, 2019, 05:20:02 PM »
Brad

If you mulch that much on avocado, how do you apply the fertilizer?  Do you just throw it over the mulch or dig up the mulch and spread the fertlizer?

The mulch lasts a year or 2.  It goes faster on the trees that get more water like avocados.

Its 16 miles inland and 1200ft elevation here.  Its a lot hotter here than near the beach.  The weather is pretty spectacular down in the beach towns and downtown san diego.

spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #41 on: April 14, 2019, 06:35:28 PM »
Brad

If you mulch that much on avocado, how do you apply the fertilizer?  Do you just throw it over the mulch or dig up the mulch and spread the fertlizer?

The mulch lasts a year or 2.  It goes faster on the trees that get more water like avocados.

Its 16 miles inland and 1200ft elevation here.  Its a lot hotter here than near the beach.  The weather is pretty spectacular down in the beach towns and downtown san diego.

  If you just have a couple trees to do then you can just spread it over the mulch and then work in with your hands and then hose it real good. 

Im going to have to put a disclaimer on all my posts that people shouldn't do what I do as everyones situation is different.  Most residential areas in sandiego have garbage soil.  Clay, rock, no drainage.  So maybe lots of mulch or lots of fertilizer will drown and burn you tree.  My soil drains super fast so I can mulch hard and fertilize and flush my soil etc.  So be carefull with mulch and fertilizer.  You got to use some moderation and judgement. 
« Last Edit: April 14, 2019, 06:46:22 PM by spaugh »
Brad Spaugh

SeaWalnut

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #42 on: April 14, 2019, 08:52:53 PM »
That guy that told never to mulch a grafted tree ,i think he sayd that because somme people use mulch in excess and if   you use thick mulch that covers the graft its bad just like plabting the tree with the graft under the soil level.Use less mulch so that you dont get past the graft .

JoeP450

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #43 on: April 15, 2019, 01:06:40 PM »
I have a few palms in my yard and they are always dropping fronds especially the self cleaning arica palms, so I strip the fronds and through the leaves around the base of the trees, here is my oro negro avocado.

 


Only costs me some extra time 😎

-Joep450

zephian

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #44 on: April 15, 2019, 01:23:35 PM »
I just rented a chipper for a major cleanup and chipped many kinds of trees I have removed from the yard. I plan to amend a large section of my yard with compost then spread this pile on top.
I got probably 10 yards of mulch out of it to spread around. my 'custom blend' includes

Fruitless plum,
Cherry,
Palm,
Bay Laurel,
Sycamore,
Persimmon,
Last years christmas tree,
some other bush/trees with hard blue berries that stain my concrete

-Kris

behlgarden

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #45 on: April 15, 2019, 03:42:24 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.

very fresh raw mulch can kill the tree when combined with water. The mulch gets hot, very hot if its fresh wood clippings as its trying to decompose, similar to how compost gets hot. that heat can literally kill plants and trees.

shinzo

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #46 on: April 15, 2019, 03:52:48 PM »
My neighbor just told me that landscapers had heavily mulched her avocado tree (week or 2 ago?), and it quickly died. It was a large tree. The stump is at least 2 feet in diameter. Will try to get more info.

very fresh raw mulch can kill the tree when combined with water. The mulch gets hot, very hot if its fresh wood clippings as its trying to decompose, similar to how compost gets hot. that heat can literally kill plants and trees.

Which minimum thickness ignites the heat process? do you think even a thin layer would become hot in moist conditions?

behlgarden

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #47 on: April 15, 2019, 04:01:03 PM »
I don't know thickness but I was always told to use mulch that has gone thru the process of initial heat dissipation. Usually that is 2-3 months in a pile.

SeaWalnut

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #48 on: April 15, 2019, 04:06:53 PM »
Mulch on its own doesnt gets hot because it lacks nitrogen.But if you add a rich nitrogen source like fertiliser ,over the mulch,then,the decomposition process will start and could get hot,especially if you have a big pile of mulch.Mulch from fresh material it also sequester nitrogen from the soil .I use it only 5-10 centimeters thick in my orchards without causing problems.

pineislander

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #49 on: April 15, 2019, 05:05:20 PM »
I have a tractor mounted chipper and point the chute directly into my truck for easy transport. I've applied fresh chipped mulch from legume trees (Acacia) and applied 4 inches thick with no problem. If it is thicker like a pickup truck full it will heat up. Like the video I posted from Australia above says, however, some fresh chipped material can be harmful and they suggest letting it age. They also show a test which involves soaking the chips in water to see it they stain the water. I will say that aged mulch has significant benefits and gets better with age. I sift out old mulch which has been decomposed and get a fairly good potting mix.

 

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