Fertilizing

Morning,

I'm using miracle grow 20-20-20 for my trees in powder I mix with water.

The package says to use X amount of powder per X amount of water for potted plants and a higher quantity of power for outdoor non potted plants.

Should I use the recommended amount for potted plants for my potted trees? Or should I use a higher concentration since they are trees and not plants?

I had the same question re. Plant Prod 20-20-20 (Canadian) and contacted the company, a specialist got back to me and said to use it at the weaker houseplant mix rate. However I had been using it at the higher dosage for some time (half of last year and the first three feedings of this year) and all was ok. I then suspected a problem with 3 trees ailing which made me inquire here and to the company, I got no response on that directly here but some good advice on feed in general re. my circumstances. After looking into it some more I don't think it was over feeding on two of the three trees, the woman at Plant Prod said over feeding symptom was browning of the leaf starting at the tips. The third a juniper had the buds turning a straw colour and was dropping it's mature foliage also the same dull colour but it had Cedar Apple Rust this spring and I had treated it with Monterey Fungi Fighter (2 apps. 14 days apart) a month earlier. possibly that, it's weakened condition and the fertilizer together was a problem. I did the same treatment with other trees (Cedar, Red Cedar, 2 x San Jose Junipers) and no trouble. I flushed the pot out with water and that helped but it will take some time for what is all ready in the tree to run it's course. I have now reduced the mix rate to double the house plant and half the garden rate, right in the middle for the other trees.

Chris

also depends on what type of substrate your trees are in and how often you fertilize...

more often = weaker fert

less often = stronger fert

organic substrate = holds more of whatever you put in

inorganic substrate = (generally) holds less...

and a mix of the 2 = holds more or less   

kevin

Well, bonsai (trees) are also "plants." But semantics aside, use the dosage for potted plants.

For EVERYTHING you ever need to know about fertilizing bonsai, go here:

http://www.evergreengardenworks.com/fertiliz.htm

Thanks Jim,

That was simple and interesting.

Chris

What Jim said. Brent at evergreengardenworks has been a great source of information for me. That article on fertilizing is just the tip of the iceberg, there are so many great articles on that site, especially when it comes to the horticultural side of bonsai. Brent is right when he says many bonsai authors are too long on styling and too short on horticulture. Perhaps this is because they assume anyone getting in to bonsai has a sound understanding of horticultural principles, but this is definitely not the case especially nowadays with bonsai attracting many people, some with no previous experience with plants and especially trees/shrubs. But I would think that more books would first cover all major horticultural practices behind bonsai, their purposes and implications (what when why), then delve in to the different styles and wiring and all that. Even then much of the horticultural information found in the most respected bonsai books is outdated, and those books are usually used for their styling tips/techniques alone.

Long story short, spend as much time on Brent's site as you possibly can. I've read most of those articles multiple times, reading books and forums in between, always coming back with a better understanding and learning something new each time I re-read the article. There are many times I wish he would just come out and say what he's trying to teach us, but he makes you think about the principles and analyze them to draw your own conclusions. I like this and think it makes for a better understanding when you can deduce what these principles mean, how they apply to bonsai, and how to use these principles to achieve your end goal. Best of luck to you.

Garrett