Can MULCH be BAD for fruit trees?

[Mr. Clean]

I have heard that mulch can be bad for fruit trees in at least two instances:  1)  mulch in contact with trunk and causes truck to rot, and 2) if soil is saturated with nitrogen, the additional nitrogen added by mulch can be unhealthy for fruit trees.  Thoughts?

[FRUITBOXHERO]

You could be right! I say just let the weeds grow all over your fruit trees thats a surefire way to keep all pest and disease away from your tress

[Mr. Clean]

You could be right! I say just let the weeds grow all over your fruit trees thats a surefire way to keep all pest and disease away from your tress

Maybe...   

[jcaldeira]

It is very unlikely a soil has too much nitrogen unless someone over-applied fertilizer.  Almost all natural soil borne nitrogen comes from rotting organic matter.  Eventually, if you don't mulch you will need to add nitrogen and other nutrients by applying fertilizers.

Mulch should be kept away from the trunk, and if misapplied can cause rot.

Another way to misapply mulch is to apply too much all at once.  Some plants have a lot of roots near the surface, and could be harmed if suddenly buried under 200 mm (8 inches) of mulch.  Better to apply 50 mm and add 50 mm every few months.

I'm a big fan of mulch.

• Moisture retention
• Soil temperature moderation
• A broad-spectrum organic fertilizer
• Weed control

[Tropheus76]

Initially decomposing mulch can use a lot of the available nitrogen but it usually isnt enough to harm the tree and it balances out in later years. Mulch is all around a good thing to have just like the above posters listed there are do's and donts to using it properly.

[zands]

The same trees that don't like wet feet are the ones you have to careful with heavily mulching

From my not too diverse experience one tree to be real careful with is avocado due to it being prone to root rot. I have killed a few by planting in too rich soil (lots of humus) that held moisture too easily and by too heavily mulching. Plus watering it it too frequently

All (most?) other trees *seem* to benefit but if it is holding them back in some way it sure isn't killing them. I am pretty sure you can dump as much wood chip mulch as you want on mango and carambola. I heavily mulch my lychee and water it every second day but maybe this is a mistake? Seems like it is.

 Topic: What fruit trees are able to tolerate wet roots?
http://tropicalfruitforum.com/index.php?topic=4128.0

*******my soil is 99% sand so is fast draining

[Mark in Texas]

I have heard that mulch can be bad for fruit trees in at least two instances:  1)  mulch in contact with trunk and causes truck to rot, and 2) if soil is saturated with nitrogen, the additional nitrogen added by mulch can be unhealthy for fruit trees.  Thoughts?

You have it backwards regarding the N thingie.  Mulch does not add N, it removes it, for quite a while, unless your mulch is mostly manure but even then most manures have balanced NPK values.  It takes additional N to feed the microbes feeding on the organics.  I use a lot of mulch, especially around young trees and in the veggie garden and I always apply additional ammonium sulfate or UAN to feed the microbes.

Mark

[Mark in Texas]

The same trees that don't like wet feet are the ones you have to careful with heavily mulching

From my not too diverse experience one tree to be real careful with is avocado due to it being prone to root rot.

There are so many variables working here, some of which you mentioned, that the use and amount of ends up being the grower's call.  What you're trying to create is that natural forest floor, covered with organic litter.

For example, my avocado trees are mulched with pine needles and leaves, about 6" deep.  I mulched my tomatoes by inverting a 5 gallon pot over them and then dumping a lot of coarse tree mulch over them.

[Mike T]

Pretty well all trees like heavy mulch regularly applied even avocadoes in high rainfall tropical areas on clay during the rainy season. Citrus can take it or leave it but still benefit on balance. Pure lawn clippings that form a mat, mulch against or close to the trunk and wood chips are sub optimal and can causes hassles. Suddenly burying surface roots with mulch that stays wet or has poor aeration can also cause problems. 
Too much wood in the mulch, especially wood chips and not enough greens does mean a temporary hoovering of soil N. If it is broken down a bit or has plenty of foliage or grass in there. The 4:1 ratio is good to keep in mind.
One other benefit of mulch is that the breakdown products, resulting fungi and other decomposers reduce phytophthora.   

[natsgarden123]

in my experience with lawn guys    weeds = weed wacker = tree damage

[bsbullie]

in my experience with lawn guys    weeds = weed wacker = tree damage

weeds = weed wacker or Round-up = tree damage

[zands]

I know a guy from Colombia who is dead set against mulch. He clears the grass in a 3ft diameter. So you will see this circle of bare earth around his fruit trees. He will drop 8-3-9 fertilizer onto this bare ground and use Black Kow in a bag which he really likes. I preached wood chip mulch to him but he avoids it like the plague. I could not get his reasoning for going his zero mulch route due to the language barrier
Mulch or no mulch he is keeping grass from robbing his feeder roots.
I see a poor little struggling mango tree nearby. The grass is growing up to the trunk so its growth is stunted. It had 4 mangoes last year and 1 this year. I mean to talk to the owner if i ever see him. IMO you can get away with this but you have to drop fertilizer to feed the roots and grass. I'll bet he uses zero or hardly any fertilizer.

His trees do OK. Grow OK

[zands]

in my experience with lawn guys    weeds = weed wacker = tree damage

weeds = weed wacker or Round-up = tree damage

Also lawngrass weed and feed sees your tree as another weed with its atrazine

[Patrick]

Mulch is a necessity to get the full potential out of your trees.  The mulch REMOVES nitrogen, aerates the soil, helps control weeds, provides humus that supports the soils living systems, and protects from harmful funguses when properly applied.  It is time consuming though, and that may make it something that would make one hope that it is harmful.. Unfortunately, and once again..... No pain, no gain..

[jcaldeira]

Mulch is a necessity to get the full potential out of your trees.  The mulch REMOVES nitrogen, aerates the soil, helps control weeds, provides humus that supports the soils living systems, and protects from harmful funguses when properly applied.  It is time consuming though, and that may make it something that would make one hope that it is harmful.. Unfortunately, and once again..... No pain, no gain..

Mulch may remove nitrogen initially, but its long term effect is to ADD nitrogen to the soil.



http://soilwater.com.au/bettersoils/module2/2_4.htm

[ben mango]

Pretty well all trees like heavy mulch regularly applied even avocadoes in high rainfall tropical areas on clay during the rainy season. Citrus can take it or leave it but still benefit on balance. Pure lawn clippings that form a mat, mulch against or close to the trunk and wood chips are sub optimal and can causes hassles. Suddenly burying surface roots with mulch that stays wet or has poor aeration can also cause problems. 
Too much wood in the mulch, especially wood chips and not enough greens does mean a temporary hoovering of soil N. If it is broken down a bit or has plenty of foliage or grass in there. The 4:1 ratio is good to keep in mind.
One other benefit of mulch is that the breakdown products, resulting fungi and other decomposers reduce phytophthora.   

I think Mango is another take it or leave it? I have heard they don't need or require much mulch.

[Patrick]

Tree mulch is very high in Carbon.  The high carbon level counters the release of nitrogen and may even remove additional nitrogen from rainwater percolating through it.

http://www.icrisat.org/what-we-do/learning-opportunities/lsu-pdfs/Carbon%20Nitrogen%20Ratio%20in%20the%20Soil.pdf
(Explains Carbon/Nitrogen relationship)


"Another drawback is that organic mulches cause a temporary boom in the population of soil microorganisms, which can tie up some soil nutrients. This boom is especially a problem with mulches high in carbon, such as wood chips."  (cited from http://main.org/aog/articles/mulc.htm)

Eventually if the carbon is used up the subsequent nutrients are released, but the nitrogen that was utilized by the decomposition process is gone!

[Patrick]

Pretty well all trees like heavy mulch regularly applied even avocadoes in high rainfall tropical areas on clay during the rainy season. Citrus can take it or leave it but still benefit on balance. Pure lawn clippings that form a mat, mulch against or close to the trunk and wood chips are sub optimal and can causes hassles. Suddenly burying surface roots with mulch that stays wet or has poor aeration can also cause problems. 
Too much wood in the mulch, especially wood chips and not enough greens does mean a temporary hoovering of soil N. If it is broken down a bit or has plenty of foliage or grass in there. The 4:1 ratio is good to keep in mind.
One other benefit of mulch is that the breakdown products, resulting fungi and other decomposers reduce phytophthora.   

I think Mango is another take it or leave it? I have heard they don't need or require much mulch.

Mango trees seem to be extremely thrifty for sure.  They do respond well to pampering though!

[bangkok]

Pretty well all trees like heavy mulch regularly applied even avocadoes in high rainfall tropical areas on clay during the rainy season. Citrus can take it or leave it but still benefit on balance. Pure lawn clippings that form a mat, mulch against or close to the trunk and wood chips are sub optimal and can causes hassles. Suddenly burying surface roots with mulch that stays wet or has poor aeration can also cause problems. 
Too much wood in the mulch, especially wood chips and not enough greens does mean a temporary hoovering of soil N. If it is broken down a bit or has plenty of foliage or grass in there. The 4:1 ratio is good to keep in mind.
One other benefit of mulch is that the breakdown products, resulting fungi and other decomposers reduce phytophthora.   

I think Mango is another take it or leave it? I have heard they don't need or require much mulch.

My Thai family has huge mangotree's and they grow in clay next to a ditch. They never do anything to those tree's, only pick mango's.

[natsgarden123]

And weeds certainly look bad in the yard. I think fruit trees should look nice, like any other trees and ornamentals.

Ill post a photo of wacker damage...its depressing to see it

[Mark in Texas]

Also lawngrass weed and feed sees your tree as another weed with its atrazine

Atrazine targets grasses, not broadleaves.  It is safe to use around trees as is glyphosate (active ingredient in Monsanto's Round-Up).

I use 42% glyphosate, a lot.  1.5 oz/gallon both commercially and around the estate.  It is the best solution to a friendly and complete weed free barrier.  Even use it in the veggie garden on a calm day using a quart sprayer.

[Mark in Texas]

Tree mulch is very high in Carbon.  The high carbon level counters the release of nitrogen and may even remove additional nitrogen from rainwater percolating through it.

http://www.icrisat.org/what-we-do/learning-opportunities/lsu-pdfs/Carbon%20Nitrogen%20Ratio%20in%20the%20Soil.pdf
(Explains Carbon/Nitrogen relationship)


"Another drawback is that organic mulches cause a temporary boom in the population of soil microorganisms, which can tie up some soil nutrients. This boom is especially a problem with mulches high in carbon, such as wood chips."  (cited from http://main.org/aog/articles/mulc.htm)

Eventually if the carbon is used up the subsequent nutrients are released, but the nitrogen that was utilized by the decomposition process is gone!

Said the same thing in a previous post FWIW.

[jcaldeira]

The primary reason that topsoil contains more nutrients than subsoil is that it has had long term exposure to rotting organic matter.   Mulch, or organic litter, is the main way that nature creates topsoil.  If there is concern about temporary nitrogen loss, mulching can be done with compost. 

My favorite soil nutrition course on the internet:
The Agricultural Bureau of South Australia's 'Better Soils' pages:
http://soilwater.com.au/bettersoils/modules.htm

[Patrick]

The primary reason that topsoil contains more nutrients than subsoil is that it has had long term exposure to rotting organic matter.   Mulch, or organic litter, is the main way that nature creates topsoil.  If there is concern about temporary nitrogen loss, mulching can be done with compost. 

My favorite soil nutrition course on the internet:
The Agricultural Bureau of South Australia's 'Better Soils' pages:
http://soilwater.com.au/bettersoils/modules.htm

Great info!

[HIfarm]

Another benefit of mulch is more earthworms.  If I dig down randomly on my land, I don't come across many worms.  If I dig where there is mulch, there are a lot of fat, happy worms.  Worms help to aerate the soil, keep it looser (less packed), and the worm castings are great fertilizer.  So, another side benefit of mulch that helps your trees.

John