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Author Topic: To Mulch or Not to Mulch (Fruit Trees)  (Read 2774 times)

johnb51

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To Mulch or Not to Mulch (Fruit Trees)
« on: April 12, 2019, 10:42:01 AM »
I know we've talked about mulching fruit trees a lot on this forum.  It's generally accepted to be a good practice, correct?  I've always mulched under my fruit trees, and it seems to be beneficial.  Well, lo and behold, when I went to purchase three fruit trees from one of the largest and most well-known nurseries in South Florida the other day (located in Lake Worth), the owner sat there and said: NEVER MULCH UNDER GRAFTED FRUIT TREES.  IT'S BAD FOR THE TREES, AND THE WORST THING YOU CAN DO.  YOU WILL KILL YOUR TREES.  Mind you, I didn't even ask her advice on this matter.  And the two guys who work there were agreeing with her in no uncertain terms.  They didn't want to hear any arguments in favor of mulching or even to discuss the matter.  Naturally my reaction was WTF???
John

poofystuff

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #1 on: April 12, 2019, 10:59:59 AM »
I have a variety of grafted fruit trees that I have had for years and have mulched with various types (wood chip, leaves, grass, straw/hay, whatever I can get my hands on for free). All are still standing and doing well.

spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #2 on: April 12, 2019, 11:02:10 AM »
I dont know about FL but I use like a foot of mulch on all my trees.  It serves many purposes.  It breaks down and feeds the plants, it holds moisture in, and it keeps weeds from germinating.  Its like a miracle product IMO. 
Brad Spaugh

Alejandro45

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #3 on: April 12, 2019, 11:33:42 AM »
I wonder why the Mrs Wilson would say that? I have watched so many videos of other gardeners organic and not. The consensus to me is that mulch is good no matter what type of gardner you are. I love mulching it adds to my poor sandy soil provides habitat to the insects, food for fungus, and insulates the roots during temp extremes.

Edit*. Also Bill Whitman and Adolf Grimal had truck loads of mulch dumped on there groves.  Those dudes did pretty good!
« Last Edit: April 12, 2019, 11:42:29 AM by Alejandro45 »

johnb51

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #4 on: April 12, 2019, 11:42:43 AM »
All I can imagine is that someone mulched improperly and killed his trees, then came back to her to ask what happened.  And she over-reacted and is still over-reacting!
John

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #5 on: April 12, 2019, 12:07:35 PM »
All I can imagine is that someone mulched improperly and killed his trees, then came back to her to ask what happened.  And she over-reacted and is still over-reacting!

Too funny i was just discussing this with a friend who has a commercial-level peach orchard. He had been scared off of wood-chip mulch, but he recently saw that i use it abundantly (within reason, see below) around my pawpaw trees and grape vines.

But yes, John to your point above - i'm almost sure this is the deal. The problem people have with mulch that kills trees is that they do the "mulch volcano" and mound it up high right against the trunk. Basically burying a few to several inches of the trunk in mulch.

This WILL kill trees (not overnight, but in time).

I think mulch can be overdone in some conditions. I put probably close to a foot (looking at you, Brad!) of woodchip mulch over what I found out to be a naturally-water-holding section of my small orchard and I think it nearly killed the trees. I have since dramatically reduced the mulch layer.

I guess i'm in the camp of Linda Chalker-Scott who is a big champion specifically of wood-chip mulch.

I've seen no ill effects.

johnb51

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #6 on: April 12, 2019, 12:19:23 PM »
My soil is pure sand so without the introduction of organic matter I won't have healthy living soil, and it will not retain any moisture.
John

spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #7 on: April 12, 2019, 12:31:16 PM »
I dont have drainage issues so a foot of mulch is golden here.  Your mileage may vary.
Brad Spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #8 on: April 12, 2019, 12:39:46 PM »
I see that you referenced a "her." If that was Marlys (lady in her early - mid 60's), she tends to have strong opinions. So the proverbial grain of salt might be in order.

That said, mulching is a tricky subject. After placing over a thousand cubic yards of mulch on my own property over the course of a decade (and creating a 6 inch+ layer of muck), I've come to the conclusion that it's good in moderation.

Pros:
 - eliminates weeds
 - conserves soil moisture
 - adds carbon and increases soil's cation exchange capacity
 - holds supplemental nutrients better (less fertilizer waste)
 - some tree roots appreciate the mucky consistency that results after decomposition (eg, lychees)
 - encourages worms and other beneficials
 - pushes pH towards neutral

Cons:
 - causes imbalances between K and Ca resulting in lower brix (can be ameliorated with copious amounts of gypsum)
 - locks up some micronutrients (can be mitigated with heavy and consistent application of fertilizer)
 - causes phosphorous to skyrocket (not a good thing)
 - many trees dislike the mucky consistency that results after decomp (eg, mangoes)
 - can add nitrogen, depending on the mulch used (bad for mangoes)
 - resulting mucky top layer (which retains more water + nutrients when fertilizing) encourages shallow root growth

I have 2 different lots. On the first lot, I created a layer of muck several inches thick. On the second lot, I added an inch or less, so I've been able to compare the two.

If you are good at fertilizing, you can create a very rich top layer of soil via the use of mulch, since the top layer (decomposed mulch) retains nutrients extremely well (this is a bad thing if you don't fertilize -- it locks up the little bit of nutrient that's naturally present, resulting in micronutrient deficiencies). I've had to add literally tons of gypsum to overcome jelly seed and increase brix on the trees on the heavily mulched lot.
Jeff  :-)

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #9 on: April 12, 2019, 01:11:15 PM »
Yeah, I think moderation and attention to your specific conditions (e.g. difference between me and Bradís situations) is key.

Frog Valley Farm

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #10 on: April 12, 2019, 02:19:03 PM »
The ideal mulch for Floridaís sandy soil is living roots, a combination of grasses, weeds and herbs kept above 6 inches.  Tall living mulch is a carbon drip system for whatís living in soil the soil life feeds and sustains the tree and provides the home for soil life like fungi and bacteria.  Most weeds that grow in Florida attract and are home to beneficial insects.  This perfect nutrient cycling system along with the cation exchange which will naturally bind nutrients and pollutants in a stable matter that will not easily leach into the environment.

There is no plant based carbon mulch that feeds the tree unless you are mixing synthetic fertilizers in it.  The synthetic fertilizers will mostly pollute your yard and leach into the environment and this will stop natural nutrient cycling.  Plant carbon feeds the soil biology.

Having a tall living mulch will trigger the cation exchange and build soil.  Cation exchange happens under tall grass at soil levels. Mulch or plant carbon added in small increments every other week are an excellent way to provide a perfect environment for trees to thrive.  A high quality compost is best for speeding this process.  I have found biodynamic manure compost tea sprays are great for building soil thru the cation exchange. The cation exchange will not happen under a thick layer of woodchips as they need grass roots and fungi to bind the organic matter and nutrients into soil structures.  Eventually the carbon from thick mulch will get into the soil with the help of worms, rain and segregation but this is easily leached and will not build stable organic matter in soil. Living root system do a much better job at putting carbon and biology into the ground and for building soil thru the cation exchange.  These are facts.
« Last Edit: April 12, 2019, 02:52:54 PM by Frog Valley Farm »

chad6159

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #11 on: April 12, 2019, 02:53:17 PM »
well dang....now I am thinking I should just let the mulch I have there now just break down and not replace and let grass take over....

I know exactly what cookie monster is talking about when he mentions the "muck" I have a peach tree that has been there about 4 years and is always mulched 6+ inches, there is a layer of this black muck(I am sure all of my other trees have this also, have just never dug down below the mulch before on the others). It is also the only portion of my yard that has worms in it, so I thought that was a good thing....
« Last Edit: April 12, 2019, 02:57:01 PM by chad6159 »

MangoCountry

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #12 on: April 12, 2019, 03:15:55 PM »
If you go into a forest the ground is littered with fallen leaves, twigs, branches etc. Noone is watering or fertilizing these trees and they may be hundreds or thousands of years old. There are vast mycorrhizal networks connecting these trees and they share nutrients and water. They thrive in a fungally dominated soil that is created by the trees themselves. I believe replication of this by layering tree trimmer mulch is an ideal environment to grow trees. I have been adding mulch for years consisting of tree trimmer mulch, oak leaves and yard waste and have observed no negative effects nor mineral deficiencies. The soil life is alive and loaded with worms, fungi etc.

Cookie Monster

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #13 on: April 12, 2019, 04:15:28 PM »
There are myriad other factors. For example, the amazon rainforest gets nutrition from the sky: https://www.wired.com/2015/02/sahara-keeps-amazon-green/

Also, plants like mangoes are not necessarily what one would find in a rain forest :-).

At any rate, those were my observations from a little over a decade of heavy mulching (> thousand cu yards). There's plenty of info online indicating that my experience wasn't unique.

If you go into a forest the ground is littered with fallen leaves, twigs, branches etc. Noone is watering or fertilizing these trees and they may be hundreds or thousands of years old. There are vast mycorrhizal networks connecting these trees and they share nutrients and water. They thrive in a fungally dominated soil that is created by the trees themselves. I believe replication of this by layering tree trimmer mulch is an ideal environment to grow trees. I have been adding mulch for years consisting of tree trimmer mulch, oak leaves and yard waste and have observed no negative effects nor mineral deficiencies. The soil life is alive and loaded with worms, fungi etc.
Jeff  :-)

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #14 on: April 12, 2019, 04:35:16 PM »
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/wood-chips.pdf

One research-based opinion. But again you have to consider your situation.

Cookie Monster

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #15 on: April 12, 2019, 05:05:52 PM »
Mulch does provide a significant amount of P and K, (and N depending on the source ,ie, leafy vs woody). But the ratio of K to Ca in mulch is usually 1 to 1, which is bad for brix and flesh quality, since K takes up exchange sites that would normally be occupied by Ca. Generally want K to Ca to be 1 to 10.

You can literally watch the quality / color / flesh / brix changes by manipulating K - to - Ca ratios. I've done it.

Mulch also provides off-the-charts P in relation to K. Again not a good thing.

However while mulch provides N-P-K, organic matter locks up some micronutrients. For example, a method to ameliorate copper toxicity in soil is to add organic matter (which makes it less available).

I suppose this is somewhat dependent on mulch type. I used tree trimmer mulch, which was a mix of leaf + wood.
Jeff  :-)

pineislander

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #16 on: April 12, 2019, 07:20:38 PM »
the owner sat there and said: NEVER MULCH UNDER GRAFTED FRUIT TREES.  IT'S BAD FOR THE TREES, AND THE WORST THING YOU CAN DO.  YOU WILL KILL YOUR TREES.
I heard the same thing from a citrus nursery. "The trees will die from phytophthora."

spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #17 on: April 12, 2019, 07:45:05 PM »
Ive read that mulch can inhibit phytophthora.  Anyway, thats defiitely not true that it will kill a citrus tree.   At least with my soil.  Ive got over a foot of mulch on this mandarin tree and it is super happy.  And yes, I keep it pulled away from the trunk.


Brad Spaugh

spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #18 on: April 12, 2019, 07:50:13 PM »
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.
Brad Spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #19 on: April 12, 2019, 10:26:29 PM »
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.
Jeff  :-)

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #20 on: April 12, 2019, 11:21:26 PM »
Here in CA my piles of mulch under fruit trees do great -- they turn into a rich fungal mat, and when you pull it up you smell and see the white mycelia all throughout the mulch.  Even better for fruit trees has been 1-to-1 tree trimmings to coffee grounds for restoring barren city soils.  The mild acidification from the coffee grounds really helps with our alkaline soils and helps break down the mulch a bit faster to get some good soil sooner rather than later.  The hard part is getting enough coffee grounds.

spaugh

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #21 on: April 12, 2019, 11:35:18 PM »
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.
Brad Spaugh

zephian

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #22 on: April 12, 2019, 11:43:14 PM »
I hit 115 with no humidity in the summer too w/ high winds
I've only mulched my citrus and persimmon for one year (I'm in a fairly clay area in northern ca near a river)
I put about 4 inches around my trees and they are looking phenomenal! Huge difference with mulching around my trees.
I have super wet winter too (flood warnings yearly)
the mulch seems to help me. so far... Time will tell.
-Kris

gnappi

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #23 on: April 13, 2019, 12:09:31 AM »
I'm infected with demon sloth.

I mulch when I can get a truckload of clean tree trimmings, about once a year, not sufficient to keep a cover under my trees, but they are all doing well.
Regards,

   Gary

Oolie

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Re: To Mulch or Not to Mulch (Fruit Trees)
« Reply #24 on: April 13, 2019, 12:59:51 AM »
These are facts.

Hmm, should previous statements made by you also be considered in the same manner?

Most of our Mangos are pushing flowers even the Sugar Loaf. Though at 1ft tall it might be a bit too small. I was surprised with the efficacy of various drenches these young trees got and even though I could clearly see copper was sprayed at zills, the rhizosphere was soon colonized by arbuscular mychorizal fungi as shown in the photo.


I'm still researching Arbuscular mycorrhyzae, and no matter how much I read about them I find an absence of purported fruiting bodies. Or were you referring to something else in the photo?

I just have a hard time believing anyone who refers to anything scientific as 'facts' and goes around rubbing it in people's faces. Life's a lot of grey, I don't often appreciate the 'Black and White' outlook as much I guess.

 

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