Fertilizing newly planted trees

General Fruit Growing
#41

it’s a bit heavy on the “hear say”. Would be more useful if you could tell who said it to you? Or what the logic/mechanism behind it is?

Since N is so water soluble and easily leeches away with rain, and since in most places you get heavy rain in the dormant season. I don’t see any significant uptake happening. I think a fall/winter N application on the soil will mostly leach away.

I know here on certain soil’s it’s even illegal’s to do a fall/winter fertilizations with animal manure. (which isn’t a strictly N fertilization, but more general and slow release) Due to the N to ground water leaching.

I’m personally not that worried about a lack of N, in tree’s. If you have a healthy soil. And fertilize a bit with organic matter. N availability should be good enough. I do remember reading about calcium deficiency possibly resulting in bitter pit. And since the calcium is quite immobile (unlike N which is very mobile) that it was important that enough calcium and immobile nutrients be present at flower bud development/hardening off. It was an university extension source. I can’t seem to find it back right now. I did came across this though

http://treefruit.wsu.edu/article/fall-nutrient-management-tree-fruit/

It also clearly states N fertilization should be done before leaf fall.

and

Also seems to advise to not fertilize in the winter/dormant season. But rather late summer/fall. When bud formation is finishing/hardening off.

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#42

Drew, I have been doing fall applications for bearing age trees for 25 years, and of quick release N along with K- this isn’t new info. Carl Whitcomb writes about it extensively in his book “Establishment and Maintenance of Landscape Plants” which was copyrighted in 1987.

The topic here is fertilizing newly planted trees. Vegetative growth is best served with applications while trees are in active growth. A split app might even serve them a fraction better (to get N into the buds before spring growth) but a single app in fall would be primarily for bearing age trees with adequate N in the soil to serve them for the bulk of the growing season.

That said, even though there is limited root growth over winter, if you read the literature I posted a link to you will see that research has established the points in the season where they also are most receptive to absorbing N, and the research suggests the best time for a late season app is while they are still in leaf in early fall or the very last days of summer.

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#43

In most soils some supplemental N will spur more vigorous vegetative growth. For those of us in a hurry to get trees out of harms way and productive this is pretty strong incentive to make sure there is optimum N for max growth in establishing trees. Most nurseryman use sup N simply because it would be foolhardy from a business perspective not to. I used to think I could get the same kind of growth after a couple years using mulch that would break down into nourishing humous but then I experimented with adding extra N and the results were extremely positive in my silty loam with about 4% organic matter.

Once trees start bearing adequate crop it becomes an entirely different equation.

#44

That is true.

However the literature also cites that excessive N fertilizations leads to disease susceptible growth. (both fire blight but also Neonectria ditissima. Although i can’t find much mention of the latter on this forum. Is that only something we have to deal with in the EU on pitfruit? I’f just lost a small tree to it :frowning: )

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#45

Then I guess you better not over do it. It is very common here to dial down anything that excites pears to vigorous growth that may lead to fire blight. I’ve never lost a single tree in my nursery to it in 25 years, although it can be devastating in my region also.

I have lost trees in my nursery to rodent damage and occasionally deer damage. N. fertilization also makes trees more attractive to these pests- at least deer, based on research I’ve seen, but the killing damage I’ve gotten from them is from buck rubs and not browsing.

I very roughly estimate that trees get to salable size in my nursery about 30% sooner due to growth response to urea. In the orchards I manage it is most helpful with peaches and nectarines and I believe it helps them to live longer. It may make them more susceptible to certain pests though, such as peach scale.

In general, in most soils I believe that supplemental, quickly available N is very useful in establishing trees, after that, it depends on the soil. I usually don’t use it in established orchard trees on my land, and when I do, it’s because I’m trying to outrun something like severe weather related cambium damage. I’m not sure how much it helps.

Potassium is the major nutrient that mature fruit trees are likely to excessively mine out of the soil, but wood chips and firewood ashes can usually take care of that. And yet, that is the nutrient I have to be careful not to overdo because I believe it can cause calcium deficiency when in excess and corking in some of my favorite varieties of apples- sometimes destroying the entire crop.

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#46

I’m not sure who did the research, but the research was reported all over the place. I heard it from Joe Lamp’l who had a PBS garden show and his podcast is amazing.
I also heard Farmer Fred talk about the research on his California farmer’s report podcast
I also heard Don Shorr on his Davis Garden show mention it. Based on university research.
Joe talks about it here

“New research indicates fertilizing trees and shrubs about a month after a killing frost is ideal”
He doesn’t footnote research but did on his podcast if I remember correctly?

Sorry for late response I was out of town just got back, have to leave again till Sunday in a few hours.
The research was reported at least 3 years ago and recently another study confirmed the fall as best for trees. Not sure they did other fruit or shrubs?
If you search on google scholar you can find thousands of studies. I really have no desire to convince anybody of anything. One must do their own homework and never take the word of so called experts.
When I checked the research it confirmed at least for me, when to fertilize trees.
In landscape trees this study shows that they are more winter hardy with fall fertilizer. Again reminds me of Farmer Freds rules of gardening, everything you know is wrong. So true in this case.

Not all studies come to the same conclusion so it’s not always easy to figure out an approach that works for ones needs. Research is ongoing and continuous. Often confusing and hard to understand.

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#47

In my county it is illegal to fertilize from November 1 to April 1.
Edit : this only applies to turf fertilization.

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#48

There is nothing in what you posted that endorses the application of water soluble N after trees reach complete dormancy.

What the Research Gate article makes clear is that the Growing a Greener World article makes false statements about fall fertilization being a recent discovery given the dates of research cited in the RG study. The GGW says nothing about the specific fertilizers they recommend applying in late fall.

Just for the record, so forum members won’t be confused, the consensus of science is that water soluble N should not be applied in the late fall after trees lose their leaves.

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#50

I agree with allen. All evidence that has been posted here. And all evidence if seen on university extensions and articles points towards dormant season N fertilizations being a bad idea.

than you should not believe his claims about said research. Simple as that.

I don’t know Jope Lamp’l or ever even seen any of his work. But as far as i could figure out from his own website on his expertise. It is with advertising and business. He is not a horticultural scientist, as evidenced by his extensive use of evidence and scientific sounding terms. Without doing any of the work backing them up. That’s how advertising people communicate. Not scientists.

you have made multiple claims, saying that those are research based. Than referring to “i heard it somewhere”

And now your basically saying “you go search for the proof of the claims i made”

Crapemyrtle (Lagerstroemia indica), which is marginally hardy at the test location, and red maple (Acer rubrum) experienced statistically significant, but not biologically significant, loss of hardiness in January and February due to some fertilizer treatments.

And the one research paper you did post, and summaries you seem to have taken the wrong conclusion from.

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#51

If consensus among the majority of scientists is a dirty word to you,

When is something “actually scientific” in your mind than?

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#52

There is nothing that was posted here that showed either research or anecdote supporting fast release N application during dormancy for newly planted fruit trees, so it appears you really simply used this as a platform to spurt out personal beliefs about politics and religion.

I didn’t notice anything here about dormant fertilizing strawberries with soluble N- could you at least point that out to me after exposing me to ideas that don’t belong on this forum… again.

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#53

Joe Lamp’l is actually a respected horticulturist AND excellent businessman, riding the organic gardening wave (fad, in my book, and I was totally anti-synthetic for years, starting around 1966). However, nothing Drew posted showed him endorsing applying quick release M during dormancy for trees or anything else. We all make mistakes (I seem to make more every day)- not everyone owns up to them, but readers of this forum need to be presented genuine information without distortion.

People who use names like Joe Gardener have likely crossed the line into the world of entertainment.
I believe that Drew tends to love a good showman.

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#54

Fertilizing newly planted trees

Newly planted could mean anything from starting a seedling in a nursery ,to planting a well feathered tree.

To me , my goal for each is similar.

To achieve optimal growth at each stage, not excessive.

Don’t want any deficiencies, nor excess.

Assuming other nutrients in balance.,nitrogen and water ( need both )is like the gas pedal for growth. I like to have a “medium level baseline “of nitrogen from organic and or time release sources, using water soluble forms to give them a “kick “ when needed.

I believe ,Spring flush is when a high nutrient Status is most needed.

I also think that first flush relies ,in large part to what has been stored inside the plant from the previous growing season, spring applications coming into play a little later.

What I want is… a good amount of shoot growth in the spring,dark green efficient leafs for the season., no late season growth that won’t properly harden off before cold.

High levels of organic / time release nitrogen, and a wet late summer can cause excessive late growth, and should be avoided. We can’t always control the water.

Lack of water ,late summer is usually what slows growth, allowing things to harden off, but can’t always be counted on.

One benefit of soluble nitrogen ( urea , nitrate , etc ) is they are quick acting then only available for a short time, this allows control of fertility over time.

Turning on and off growth,.

Since they are like a salt and short acting, splitting the application is often best.

We don’t want to stress young trees with too much salt. ( fertilizer ).

So split application and adequate irrigation is in order.

I usually stop soluble nitrogen application by July 1st.

Fall fertilizer …

I have been applying nitrogen in early fall for the last 3 years with good results.

I wait until the trees have absolutely decided to stop growth, and are just thinking about Turing color. Usually September here.

I have noticed a better spring flush since I started fall application.

No noticeable winter injuries from fall application.

I believe the trees store this nitrogen inside, to be used for spring growing.

I would speculate that temperate trees have adapted to recycle nutrients from the leafs that fall . In the autumn. That’s my theory,how late this occurs , if at all , I have no idea ? I assume absorption would be water and temperature dependent ?

I assume the soil ( root ) temperature is warmer in late October than it is in March or April here.? But dryer. I usually fertilize just before leaf fall.

I push my trees in such a manner, because I want nursery trees that will grow quickly. Hit the ground running when planted out. Also pushing them once planted ,to out grow the deer. Hopefully within 3yrs.?

I usually only use this high fertility treatment for young trees.

Just for quick establishment. Once firmly established, and out growing the deer, I rarely fertilize.

No peer reviewed references , just my observations of what’s working here.

A note about urea …

Surface application of urea with out water can result in very high losses to volatilization in a few days. … ie . It just evaporates into thin air !

Need water to get it into soil.

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#55

@Hillbillyhort, thanks for your perspective as well.

When you do a fertilizer application on young trees in early fall, are you using a one time liquid dose? Could you explain more of the mechanics here? I’m thinking of experimenting w/ your described method on a few smaller (1st leaf) trees to see if I can get the same boosted spring flush you saw.

#56

Incidentally and for the record, my recs were not for immediately after planting bare root trees. After transplanting it is generally considered useless to apply nitrogen until the trees have recovered enough to process it.

For apples you will likely see no benefit by fertilizing the first year, although it may help to do a late app to accelerate first growth the following spring. For peaches you should probably hold off until the trees are growing and fully leafed out.

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#57

for the record to than.

If your on a well fertilized (manure over past years) or high CEC (cation exchange capacity) soil, like clay. You will likely also see a lessend or delayed effect from specifically timed fertilizations.

However in tree’s in pots or on really sandy soil (especially if you have a wet dormant season) you will likely see larger results from timed N applications (applications in spring/growing season)

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#58

@alan
Yes, I would even generalize the recommendation to not fertilize immediately after transplanting to any plants.

This year, I planted 20 trees in January and 15 trees in March, and didn’t fertilize until May.
I fertilize opportunistically during dry periods (twice monthly) when I need to water anyway. I add in fish emulsion, collected bladder output :smile:, or both. I add more N to stone fruits than other tree types.

At first, I was not planning to fertilize at all, but this thread and changed my mind. I really appreciate your recommendations and experience.

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#59

I usually use a water soluble form of N with micros ,in split applications at a lower dose rate , like peters ,etc. On potted nursery stock.
I believe multiple lower doses spread over some time is more effective, less stress on plants , hedges you loss to leaching…

“”Fertilizing trees dose not have to be a “ all or nothing “ affair ! “”

Even very small amounts repeated over time can be very effective.
A heavy rain after application can result in high loss to leaching.
We don’t want our fertilizer ending up in streams, and we don’t want to loose it. We can not control how much it rains, or when?
The soil needs to be moist for plants to absorb nutrients.
A injector , hose end sprayer, watering can, tank in truck ,…
Are methods I have used.
I can’t say a specific rate, other than multiple light applications over time seems to work best.
People say not to fertilize a barefoot tree at planting, this is generally good advice.
But a small ,” very small pinch “ of soluble fertilizer in a five gallon bucket of water can help. Too much is definitely bad !
Again , it’s not a all or nothing thing, but a matter of degrees.
Best to error on the side of caution. More is not allways better. !
An other idea is to foliar feed in the fall.
I believe trees reabsorbe nutrients from the leafs in the fall , before they drop. if applied a week or two before the start changing color seems good. Little worry about leaf damage ,even at high rates, they are going to fall anyway.
Can help with foliage diseases by increasing the nutrients in the leafs , making them rot better… destroying leaf diseases ,

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#60

i think your suggestion of foliar feed in fall is excellent.
Less leaching. Probably higher uptake etc.

But it might increase frost susceptibility slightly. So i would be careful on the plants that are sensitive to early frosts.

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#61

@oscar
What types of trees do you have in mind that are most sensitive to early frost in fall?