S.T.E.M. - soluble trace element mix

maple_grove_gwFebruary 15, 2012


I have been reading about some of the interesting soils described here by Al and others, and am excited to try some of them this spring. I think it's really great that you guys are willing to share your time and expertise to help others become more proficient gardeners.

My question regards the value of S.T.E.M. as micronutrient source in a potting mix. I am focused on the first word, soluble. If I incorporate a Tbsp of S.T.E.M. into 3 gal pine bark etc., I would expect that it would get washed away pretty quickly and not function as a long-term source of micros. The product sheet from Peters that I came across describes its use in fertilization, rather than as a medium-term ingredient in a soil mix. When I first read the recipe for the 5-1-1 mix, I was unfamiliar with S.T.E.M. and I assumed that it would function as a slow-release source of nutrients. What is the anticipated lifespan of S.T.E.M. in the soil? Would it not be better then to use Dyna-Grow FP or something where the micros would be applied consistently, rather than relying on CRF and S.T.E.M. where the micros may get washed away relatively quickly? Or is the feast-and-starve routine sufficient for micronutrient application? Is there an alternative to S.T.E.M. for soil incorporation that might be more effective and long-lasting?

Sorry to bombard you with questions about this - I'm trying to assemble my ingredients now, and I'm trying to decide whether to use CRF/S.T.E.M. or stick with FP application. I would imagine this has been discussed here before but my search did not turn anything up.



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tapla (mid-MI z5b-6a)

Try Scott's Micromax for anything long term where you feel you might need supplementation of the minors.


STEM isn't very persistent, so you'd need to apply frequently, which would probably nullify the reason for using CRFs in the first place.

It's hard to beat regular applications of FP.


    Bookmark   February 15, 2012 at 1:53PM
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Hi Alex. Dynamite's Organic All-Purpose is a 3-month release with micros. They may have other CRFs+micros in their product line, but I have obtained excellent results with this one.

Here is a link that might be useful: Dynamite

    Bookmark   February 15, 2012 at 3:54PM
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Thanks guys, that's helpful.

After reading through 3 binders worth of "Container Soils" threads a couple of months back, I don't know why I had S.T.E.M. stuck in my mind as a suggested micro ingredient for the soils.

Thanks, 41, I appreciate an alternative to the Micromax since the Micromax seems difficult to find in anything smaller than a $90 bag. The Dynamite product you suggest is described as a complete organic fertilizer including all essential micronutrients. I have seen it stated that organic fertilizers are not well suited to use in containers since they likely do not contain the right populations of microorganisms needed to metabolize the fertilizer to its active form. What's your take on this, with respect to Dynamite?

Thanks again,

    Bookmark   February 15, 2012 at 4:51PM
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Alex - I've read that too, but it hasn't been my experience. I start all my transplants in a soil mix which includes about 1/3 of Dr. Earth's potting mix. It's an organic mix which has forest humus, worm castings, mycorrhizae fungi, and some other good stuff. These comprise a small fraction of the mix, but apparently enough to jump start the processes necessary to break down the organic ferts. If you're using a 100% "soilless" mix, I would suggest adding some well-aged compost or similar organic ingredient to accomplish the same objective - not so much as to affect the aeration and drainage of your mix, though. I'd keep it at

    Bookmark   February 15, 2012 at 10:39PM
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tapla (mid-MI z5b-6a)

MG - Earth Juice's 'Microblast' is another possibility as a source for the minors if you're still thinking along those lines.

I've always squeezed the best results out of all of my plantings by paying closest heed to the soil's structure, rather than any potential nutrient content, and relying on good soluble fertilizers that provide nutrients in immediately available form as the nutrient source. I much prefer the precise control and surety of nutrient delivery of that approach, to any of the many other alternatives I've tried.


    Bookmark   February 17, 2012 at 12:53PM
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I am going to try this in my 18 gal. 511 containers for vegetables this year.Supposed to contain micro-nutrients and calcium.


Reading from the label it is 9-4-12 and contains:

3.5% calcium
1.4% magnesium
7% sulfur
.05% copper
.9% iron
.35% manganese
.1% zinc

The label is a bit vague on application. Talks about diameter of the container. Like that helps huh?
I have to guess to use it like Osmocote, 1 tbsp per gallon.

I may use FP if things look like they need it.

    Bookmark   February 18, 2012 at 10:44AM
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Thanks, Jay that's very helpful. Looks like it doesn't contain the ultramicros (boron, molybdenum, etc.) but otherwise it looks pretty good. I always wondered why Osmacote doesn't sell something like this (or anyone else for that matter, as far as I could tell). We'll see how the price compares...

    Bookmark   February 21, 2012 at 12:51PM
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In case you give it a shot,
I contacted the MG people about the application and they say to go by the rates as written. I can't say I agree. At worst I guess it could be applied on top and mixed in to the top inches as shown on the label.

    Bookmark   February 21, 2012 at 8:25PM
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