Question I live on a largw agreage with over a hundred evergreens
I have used 11-34-0 & 11-62-0 fertilizers from a farm supply store. Why is there no potassium in this type of fertilizer and is this gooD for my trees.? I just spread a couple of cups or two around the drip line they seem to do alright. I live in Canada so winter can be tough on these trees. What would you recommend for my tree at a reasonable cost and easy to apply
AnswerPotassium shortage shows up in Evergreens that PREMATURELY drop large numbers of needle growth.
How long should Evergreen needles last? Depends on the Tree.
In its sheet on 'Needle Drop in Evergreens' by the late garden author and professor Harold Davidson, Michigan State University Extension points out, 'Needles usually last around three years. Juniper and Douglas Fir needles last for 10 or more years, while Bristlecone Pine needles can persist 30 years. Arborvitae and White Pine needles turn brown or yellow and drop in the Autumn of the second year, and Taxus (yew) needles commonly turn yellow and drop in late Spring or early Summer of the third year...' The full sheet is posted for your reading enjoyment at their website:
web1.msue.msu.edu/msue/iac/disasterresp/HORTICULTURE/03900111.pdf
What I'm saying is, IF you think your Evergreens NEED Potassium that they are not getting, IF you think they have SYMPTOMS of Potassium deficiency, don't just run out and dose up your Soil with Potassium Fertilizer. This is not the same as irrigating your plants. It's more like giving them too much HEAT!
Why?
Because excess Potassium, like excess Heat, does BAD THINGS to Trees and other plants.
Because unlike Nitrogen, which leaches, evaporates, and vanishes quickly, Potassium STICKS to Soil. And it stays there until someone uses it.
If that someone happens to be your Trees, and they already have enough Potassium, they'll be getting TOO MUCH Potassium. And bad things start to happen. The most common of these bad things is Magnesium or Calcium deficiency.
Why go to the trouble and expense of fertilizing your beautiful Trees if they would be BETTER OFF left alone?
Look at the facts. You don't know if your Soil has plenty of Potassium, or Phosphorus, or even Nitrogen this season. Fertilizing is not like other kinds of care. It's not the same as combing their hair. Or changing the oil.
Want to do something special this year? Want to take your tree-hugging self to the next level? Look at state of the art silvan care. Get your hands on some commercial Ecto-Mycorrhizal Fungi for your forest.
Most shrubs, most conifers and hardwoods build strong friendships with these nutrients-capturing beneficial Fungi. You can buy them in many places now, internet and garden centers (although it has not hit Home Depot or Lowe's yet) as little containers of powder. You just sprinkle them around just before it rains, and let Nature take its course.
The USDA Forest Service funded a report a few years ago for the Georgia Forestry Commission on this subject, 'Mycorrhizae: Benefits and Practical Application in Forest Tree Nurseries'.
These guys explained how these Mycorrhizae work: 'Specialized root-inhabiting Fungi form beneficial associations with all forest Tree species. These Fungi invade the feeder root tissues and form modified roots called Mycorrhizae (Fungus-roots), which greatly increase efficiency of nutrient and water uptake. Most plants require Mycorrhizae for normal growth and development in natural Soils.' Here's the report published online:
www.forestpests.org/nursery/mycorrhizae.html
They know a lot about growing Trees down there in Georgia. And they have some clear opinions about how to take care of them. In that report, they recommend that you keep CLOSE WATCH on Phosphorus levels. 'Available Soil Phosphorus should be maintained between 75 and 100 parts per million... Less than 50 ppm without Mycorrhizae will inhibit seedling development, and higher than 100 ppm will inhibit Endo-Mycorrhizal development. Six to eight applications of nitrogen (50 lb per acre, as ammonium nitrate) are also recommended.'
Let's read that again.
'...higher than 100 ppm will INHIBIT Endo-Mycorrhizal development.'
You DO NOT want to inhibit your Mycorrhizae. They are your secret weapon in the Woods. These Mycorrhizae are FANTASTIC feeders of Phosphorus. They pick P molecules off Soil particles and feed them one by one to feeder roots at the bottom of your Trees. Don't worry, they don't do it for free -- this is a trade, nutrients and moisture in return for special services. A match made in Heaven.
Who knew?
Some more 21st-century Soil Science: Your Trees grow best when you feed them their Nitrogen in the form of AMMONIUM. Take a look at those bags from the farm supply store. Do they have Nitrate-based Nitrogen (the kind you use for Grass -- NO3)? Or is it the kind of Nitrogen they like, Ammonium-based (NH4+)?
Now, if you have any trouble sleeping tonight over this, John, print a copy of this treatise on 'The Vertical Distribution of Ericoid, Ecto-, and Arbuscular [Endo-] Mycorrhizae in a Mixed Species Forest Soil: Correlations with Soil N and P Distribution and Effect on Root Topology'.
These researchers used DNA sequencing to identify the Fungi types in roots -- a technology that no one had 20 years ago. This is the kind of new world we are looking at when we do all those adoring things to plants in our care. Like I've said before, It's been 100 years since Franz Huber cooked up the first batch of fertilizer in his German lab. (Huber was figuring out ways to increase the food supply for the German people. He won a Nobel prize for his fertilizer work.)
But that was 100 years ago.
We know A LOT more about molecules and synergies in the Soil, about DNA and chlorophyll. We've cloned sheep, we've bloomed the first Blue Rose, we've sequenced genes. Why fertilize like your great grandfathers (God bless them all)? It's 2008!
Oh, here's that bedside reading:
coweeta.ecology.uga.edu/theses/2004_rachel_uga.pdf
Guaranteed to put you right to sleep in 4 minutes or less.
Get your Soil tested.
Any questions?
