Fertilizer Ratios and Effect on Dilution...

mfp1028

sorry to sound like a published scientific text.
I keep hearing (actually reading) that for summer it is good to lower the fertilizer requirement for twigs. For example, let us say that you use a 10-10-10 full strength in the spring and you (or i, he, or she) wish to use a 1-1-1 fertilizer in the summer. Alright here is the question.

Would diluting that 10-10-10 fertilizer 10 to 1 (water to fertilizer) essentially turn that fertilizer into a 1-1-1Fertilizer?

Good day
mike

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TreeBay

As example I have a bottle of Schultz African Violet Plus fertilizer, which has an analysis of 8-14-9. Those numbers are the percentage by weight of the NPK - 8% Nitrogen, 14% Phosphate, 9% Potash. Now, you would never apply it at the "full strength" as you say (to african violets or bonsai at least). The recommended concentration is

7 drops per quart of water if used continuously
14 drops per quart if used once or twice a month.

So this 5.5 oz bottle is good for something like 25 -50 Gallons of fertilized irrigation water when used at normal strength. And full concentration is about 100 times recommended strength!

Regardless of that, if you wanted to reduce fertilizer application to about 10% normal, if you were using it once a week, you could cut your fertilizer application to once every two months and get a similar result to diluting the fertilizer from normal to 1:10 of normal.

Personally, I find it easier to play with the frequency of application, or simply skip the hottest months altogether.

Now I prefer to use organic fertilizer in cake form, so I simply don't apply it as frequently and often remove much of what was already there as the heat builds, or stop applying it altogether until the brunt of the summer heat passes

To answer the technical question, you'd be best off talking to Soildoc, but it comes down to the amount of fertilizer that is retained in the soil over a given period of time, which is a function of concentration and frequency of application, and characteristics of the soil, like CEC which is a measure of how sticky it is to certain ions, and how fast draining it is.

Hope that helps!

Regards,

Matt

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Carl_Bergstrom

My turn to jump in and ask a question:

So I go out there and decide to water at full recommended strength every two weeks, say, rather than at half strength every week. And this presumably works great in my big old growing beds out back. But what about in my well-draining larch forest in its big flat pot with only about 2" of almost 75% lava rock soil?

What fraction of the fertilizer that I pour in there this week will still be there next week after 4 or 5 thorough waterings? Doesn't this mean that I'd be better off watering on a weekly basis at whatever strength that schedule necessitates?

-Old Mister

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splinter

Good question, OMC - I am curious to know the answer...especially since I have ruined several trees by unknowingly overfertilizing.

TreeBay

Good question.

Very little of a water soluble fertilizer will remain in the soil after a week or so watering, particularly in a soil with low CEC like lava rock. That's another reason to use organic fertilizer. A little leaches into the soil every time you water.

You can get a similar effect with chemical fertilizer by using a fertigation system like this one that will supply continuous fertilization at the selected concentration. At least that way you aren't flushing out fertilizer with fresh water; you're flushing out fertilizer with more fertilizer! In other words, be prepared for some green spots on the lawn!


"Dilution ratio is adjustable, so you can feed quickly (4 Tbls./gal.) or slowly for months (1:2,000) each time you water. "

6413
E-Z Gro Fertilizer System 3/4 gal. tank

The 3/4 gallon tank is fine. I bought the larger thinking it would be necessary, but you can put a lot of fertilizer in a 3/4 gallon tank, believe me!

Just set it up with the desired ratio and it will meter out that rate until the supply is depleted. There are fertilizer injection systems that like Dosatron that provide more consistent metering but they cost about 6 times as much. I have one of these I use in the growing grounds with DynaGro, but I'm an acclaimed organic fertilizer nut for my stuff in bonsai pots.

There's a pdf file on line so if you have acrobat reader you can look at:

http://www.charleysgreenhouse.com/c...arnMore=1#LMore

BTW, if you haven't already found them in bonsaiTALK Links, there is also a great series of articles by Brent Walston. The fertilizer one is here:

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

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

Regards,

Matt

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Carl_Bergstrom

Thanks, Matt - great tips.

Today was fish emulsion day for my trees. After thirty minutes of dripping rotten fish oil all over myself and fighting off the undesired attention of both the dog and a couple of dozen local wasps, a system like that is starting to sound really, really good.

You think one of those would be consistant enough for bonsai use? Seems like a really nice product, and I don't really want to shell out the money for the injector system just yet.

Best regards,
OMC

(I've read Brent's articles before, but I find that they are so full of information that I only manage to absorb the small fraction that I'm somehow ready to hear each time I read them - so I'll definitely go back for a repeat visit to the fertilizer ones. Thanks for the suggestion.)

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Soildoc

I might as well jump in here. Treebay has been doing a great job of answering the questions so I thought I'd keep my mouth ....er fingers, quiet. I'm not sure it's possible to overfertilize bonsai in the technical sense. I don't think it is possible to keep extremely high levels of fertilizer in a well draining bonsai soil that is watered frequently. Most of the added fertilizer is leached. I think the problem of overfertilization comes from using the wrong formulation of N with the result of "burning" the plant roots. Personally, I use the Schultz's stuff at full strength once a week and water every other day without any problems.

Now that I've rambled all over, the answer to your question, Mike, is yes a dilution of 1 to 10 would create a 1:1:1 fertilizer.

splinter

The more I read, the more I realize how lucky I am that any of my bonsai have stayed alive! I don't fertilize nearly as often as what you're suggesting, mainly because I've gotten a little phobic about overfeeding. This is definitely an ongoing challenge. When I look through the photos in the photo gallery, I'm awed by the great trees that are shown. I hope that eventually I will come up with the right "mix" for my climate, etc. Right now it still seems kind of hit and miss, and I'm about 2 years into the hobby.

Soildoc

Don't get discouraged. If your trees are still alive you're doing something right. I fiddled around for a long time trying to find a soil mix and fertilizer scheme that worked and I'm still not sure it's the best one for me.