Fertilizing...when to do it?

[Sapling]

I have read some of your discussions on fertilizing and am looking for opinions and advice on when to do it.

We are currently using a liquid injection method and have been doing a spring and fall application for our clients. The spring has been a 21-7-7 and fall 8-20-30. Any opinions and / or advice on this subject would be appreciated. I am also wondering if anyone can recommend a good reference for fertilization. I am looking for something current and relevant to my area (southern Alberta, Canada....prairie / borderline rocky mountains).

 

[treeseer]

http://secure.isa-arbor.com/store/B...eries-BMP-br--Tree-Fertilization-P174C59.aspx

 

[Cowboy Billy]

Thanks for reminding me. It should be warm enough this week to scoop up some horse pies and throw under the pines outside of the pasture. I have been wanting to try it instead of chemical fertilizer but I keep on draging it arcoss the field before I rember. I had some little cedars not more that 2' high in the horse pasture when I moved horse in in 2002. Now they are 8' to 12' tall.

Billy

 

[Sapling]

Thank-you!!!

 

[arbor pro]

Fertilization times differ depending on region and plant species. That said, it is generally better to fertilize in smaller amounts throughout the growing season vs one large single application. Also, bear in mind that if the tree is located in a turf area and is getting fertilizer that is broadcast or sprayed onto the lawn, that is usually quite sufficient for the tree - no additional fertilizer is necessary.

Also, it is generally best to avoid fertilizing with a high nitrogen content during high stress periods. Doing so will promote new growth on the tree and use up energy reserves that the tree needs to cope with stress from disease, insects, drought, etc. Nitrogen is best applied in early spring before leaf out or late fall when the tree is building its reserves for dormancy.

In my area, a lot of folks make teh mistake of fertilizing with nitrogen during the peak of summer when they think the Elm and Birch trees need an extra boost to deal with the heat and drought. Doing so, promotes growth which depletes a tree's energy reserves; thus, making it weak and more succeptible to attack from borers which are wiping out our elms and birch.

Good intentions often result in long-term problems if you don't know the biology of the plants you're trying to help.

Your local extension office or university would be your best info source for your area.

 

[underwor]

Best time to fertilize! When the tree NEEDS it, do a soil test or better yet a tissue test and then determine what is missing for NORMAL growth. If anything is needed, then follow the rest of the advice.

Remember, trees can not eat N, only carbohydrates made by leaves. Any N beyond what is needed allows for faster insect and disease growth, while stressing the tree's immune system by tying up carbohydrates that could go to growth and defense.

 

[arbor pro]

Bob,

I was trying to reply to the question of fertilization as my mentor, John Ball, professor of Forestry at South Dakota State University, would have. It's great to know that we have members of academia weighing in. Thanks for pointing out the need for a soil test before anything else.

Fertilizing a tree without knowing it's nutrient needs is a bit like prescribing treatment for a human patient who has never had an examination. Why prescribe potassium if the (human) patient's diet consists primarily of bananas, potatoes and squash - all high in potassium?

It makes sense to find out what the patient really needs first. Otherwise, you're just wasting time and money and possibly doing more harm than good.

 

[Sapling]

Best time to fertilize! When the tree NEEDS it,


I am speaking in a general sense. We have many homeowners who want to implement a regular fertilization program to ensure their trees are getting what they 'need' (I am not saying they all need to). In a perfect world every tree owner would regularly conduct soil tests and would have the results for us when they called. I am starting to recommend this to people as I believe they should and need to educate themselves on their trees and proper health care.

I realize that every tree is different and I have been doing a lot of research on what, when, how, etc. I find that there is so much conflicting information out there. I strongly believe in doing things the right way. There are so many tree service companies here who will jump at the words 'spray' or 'fertilize'. For most it is a cash cow. I like the idea of preventative maintainance and health care.

Here is my situation....we had a 'friend' working with us. He wasn't very skilled in some aspects of arboriculture but was interested in insect and disease diagnosis and treatment. He really wanted to start a fertilization branch and slowly get into types of pest treatments. We started a fertilization program and now he is no longer with us. I have been forced to take over and I am currently studying to get my pesticide applicators license. Not that I plan to start applying pesticides but I believe it is a good opportunity to learn what I can about pests and the industry. I like to be educated in all aspects of what I am doing and strongly believe education is essential (as is practical application and 'hands on' training). Right now I will carry on with the fertilization program but I would like to fine tune it to meet the needs of everyone's trees. I do not want to fertilize trees that do not need it just for the sake of a dollar. I like to think that with the proper knowledge I can offer a more personalized program. I am looking for help not criticism. For those of you who know what they are doing and have established a regiment for their customers, what are your opinions / suggestions / recommendations? I also know it is not reasonable to have every single type of fertilizer on hand for every different tree.I guess I need to do more research and get myself a good book on the subject.

From what I know about the companies around here, they all drive around in the spring & fall with their tank of fertilizer / water and fertilize all trees with the same NPK combo. That seems so general to me. It can't possibly be meeting the needs of all trees can it? Why is it that they do it this way...is it a profit thing?

 

[ATH]

From what I know about the companies around here, they all drive around in the spring & fall with their tank of fertilizer / water and fertilize all trees with the same NPK combo. That seems so general to me. It can't possibly be meeting the needs of all trees can it? Why is it that they do it this way...is it a profit thing?

Yes...I am pretty sure they see it as a profit thing. There is nothing wrong with profit - isn't that why we are in business? I really think it is mostly a lack of knowledge - both by the business and the customer.

You can make very good profit by prescribing the correct fertilization - but that takes more work. Good clients will pay more for knowledge. In otherwords, if 'Company A' says "we'll fertilize your trees for $x". Then you get a call and they ask for a bid. As long as the customber will listen just enough to your reasoning why you can't just give a simple bid (let's do a soil test, then figure out what fertilizer you need, etc...) they will see through the 'mindless' mix that the other guy has.

I know...that is dreaming to a certain degree. Look at how ChemLawn (et. al.) sells their spray programs for turf grass. There is no knowledge, IPM, planning, diagnosis, etc. They just spray what they have on the truck - and make a lot of money doing it.

 

[underwor]

I am glad to see so many good replies to this thread. One of the biggest problems we have in the tree care business is knowing what is needed for good tree growth on each species of tree. We often know what will make the tree grow faster or make the leaves a darker green, but we do not really know if it is needed. Then, even if we knew what was needed, there is no simple test for whether the tree is getting it or not. Dr. Ball was, I believe, working on a method of using leaf color and the Munsell Color Chart to diagnose nutrient deficiencies or toxicity, but I don't remember hearing anything about it lately. It would be a highly variable data base I am sure. And finally, if the tree is not getting a nutrient that it needs, is it because the nutrient is not in that soil or just not available due to pH or the effects of some highly buffering clay?

I know some companies are trying to address this issue with species specific recommendations for fertilization. Others, like myself, tend to wander around the neighborhood and see if the tree is off color or growing at a different rate than others of its species, to determine if it is more likely soil or nutrient related-- if it looks off color or out of health in the first place.

As I have often said, I can make me grow faster and have a more rosy complexion if I feed myself a lot more goodies, but at 60 years, 5'6", 200" with good BP,HR and other vitals, I probably don't need to. We just need to put the effort into education as has already been mentioned, to get the people to practice good PHC and help nature help itself. My generation has not done everything right, two things I can think of in my life is trying to help my kids and trees too much. They are both more self sufficient and adaptable than we give them credit for.

 

[okietreedude1]

If you truly want to do it RIGHT, insist to every customer that you need to do a soil test in order to acuratly give the tree the proper nutrients. If they arent willing to spend an extra $25-50 for a soil test, then they really dont want whats best.