Author Topic: Fall fertilization of bonsai  (Read 5829 times)

bwaynef

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Fall fertilization of bonsai
« on: September 24, 2011, 10:00 PM »
A lot is made this time of year of switching out our N-containing fertilizers for its N-less cousin, 0-10-10.  The proponents of this tend to cite the "fact" that Nitrogen (much less high-nitrogen) forces new growth that likely won't have time to harden off, leading to winter kill ...or at least dieback.

Others suggest that Nitrogen isn't the deciding factor in new fall/late-season growth, but poorly-timed pruning, particularly hard pruning.

Brent Walston @ Evergreen wrote an article entitled, "The Myth of 0-10-10".
Quote from: Brent Walston
"It always amazes me that folks latch on to no nitrogen fertilizer when preparing for winter, when it is the least important of several factors pertinent to hardening off."
  (You can read the article where he goes on to back up that statement @ http://bonsainurseryman.typepad.com/bonsainurseryman/2006/08/the_myth_of_010.html )

My limited experience seems to support Brent's findings.  What have others seen?  How do you fertilize your trees?  How late into the season?
 

bwaynef

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Re: Fall fertilization of bonsai
« Reply #1 on: September 24, 2011, 10:32 PM »
I didn't mean to come off quite like it reads in the first paragraph.  I'm sincerely asking what people think of the topic ...and what people's experiences are in that regard.
 

Dave Murphy

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Re: Fall fertilization of bonsai
« Reply #2 on: September 25, 2011, 08:30 AM »
I used to decrease nitrogen in my fall feed but don't anymore, and haven't seen any problems with winter hardiness.  I feed full strength miracle grow and fish emulsion throughout the growing season and assume the trees take what is needed and leaves the rest.
 

Judy

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Re: Fall fertilization of bonsai
« Reply #3 on: September 25, 2011, 08:38 AM »
Not that I have nearly as much experience as most here, but I don't change from balanced, and have never had a problem with it.  But I use a balanced formula all season, and I have seen it said that you don't need to switch unless you're using a high N (ratio) component formula. 
 

bonsaiTom

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Re: Fall fertilization of bonsai
« Reply #4 on: September 26, 2011, 05:26 AM »
Good point. Some advocate using high nitrogen in the earlier part of the growing season, balanced in mid-season, low (or zero) towards the end. If you skip the 'hi & lo' and use just balanced and are getting the growth that you want keep doing it. Some folks are searching for optimal growth and health. And that's a different topic, I'm sure.
 

Judy

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Re: Fall fertilization of bonsai
« Reply #5 on: September 26, 2011, 08:03 AM »
Yes, I imagine it's more where the tree is in it's development which way works best.  I just like to be safe, and make sure they have a consistent food source.
 

bwaynef

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Re: Fall fertilization of bonsai
« Reply #6 on: September 27, 2011, 05:51 PM »
Some people have stated that their experience has been that N fertilizer (much less high-N fertilizer) late in the season has caused unwanted growth, where my experience has not borne that out.

Without seeming like I'm trying to start an argument, has anyone here noticed fertilization causing unwanted late-season growth that doesn't harden off in time?

I wonder if that situation is more prevalent in locations that get an earlier dormancy/winter than I do.
 

plantmanky

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Re: Fall fertilization of bonsai
« Reply #7 on: September 27, 2011, 06:44 PM »
I have found that in my area zone 6b that if there is a warm fall season and a high nitrogen fertilizer is used in combination with some level of pruning that forces new growth, that new growth in a cold spell will often die back during he winter months.  As a precaution, I don't do any pruning after August and apply a good portion of Bone-meal until the trees are put away for the winter.  I'm an old school plantman and believe in bone-meal in the fall and it has worked for me for 50 years.  Being an old dog, I'm most likely not going to change what's worked.
 

Judy

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Re: Fall fertilization of bonsai
« Reply #8 on: September 27, 2011, 08:18 PM »
I really think that the pertinent thing here is the late pruning, at least in my experience.  I've had growth from pruning too late, but never from fert late in the season.  But I do balanced thru the entire season, so maybe that will be a factor as well.
 

cbobgo

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Re: Fall fertilization of bonsai
« Reply #9 on: September 27, 2011, 08:51 PM »
I solved this problem by moving to a place that doesn't have much in the way of winter. 
 ;)

- bob
 

Chrisl

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Re: Fall fertilization of bonsai
« Reply #10 on: September 28, 2011, 11:42 AM »
I'm with Judy, only seen new growth after late summer pruning.  Though my spring air layers from JM's, that I cut off and planted in Aug., are putting out a ton of new growth still now.  I'm not sure how to avoid this as it takes all summer for the air layer, and get it in soil asap to prepare for fall/winter.  I've used fish emulsion fertilizer on them, but also on other maples, and these other JMs are not putting out new growth.  So for me, I'm still learning about the growth patterns and timing of JMs.
 

Judy

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Re: Fall fertilization of bonsai
« Reply #11 on: September 28, 2011, 11:52 AM »
Chris, I'm not sure you have to worry about that new growth you're still getting as long as you can protect them from hard freezing. Are they in the ground, or trainers?
 

Chrisl

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Re: Fall fertilization of bonsai
« Reply #12 on: September 28, 2011, 01:25 PM »
They are in trainers.  I bought a small plastic covered hoop greenhouse this fall to use this winter for the first time.  So they will undergo a hard freeze, but protected from wind and sun.  I may have to add a heater to keep above say 20 degrees to protect my Bald Cypress.  I previously kept them in my unfinished basement, but it wasn't cold enough.  So this is why I'm trying something different this year (only my third winter here in Chicago)
 

Judy

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Re: Fall fertilization of bonsai
« Reply #13 on: September 28, 2011, 04:08 PM »
Sounds like you'll be ok, but I'd add that heater component to be safe. I do heat mats for bottom heat for my tender stuff inside my cold greenhouse. But I leave my BC's outside all winter with no problems... And last year we had some pretty cold temps here, some near 0.  I bury the pots -maybe I've just been lucky.
 

MatsuBonsai

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Re: Fall fertilization of bonsai
« Reply #14 on: September 29, 2011, 02:35 PM »
I typically fertilize my deciduous trees until the leaves begin to change and fall.  Then is when I remove all the leaves, light trim, remove fertilizer, and cleanup the soil surface.  No change in NPK and they seem fine.

For conifers, some I continue to fertilize well into December.  No change in NPK here either.