Fertilizer: Micracle Gro and Osmocote

bugbite(z9a FL)November 27, 2011


I contacted Miracle Gro (Scotts) about the PPM of Nitrogen in their Liquid fertilizer. After many back and forth emails they said the PPM in the straight liquid is about 940. I need 150 PPM 5 days a week. Their recommended dosage would be about 8 PPM every week or two. Am I in the twilight zone? What am I missing?

I then decided just to go to Osmocote 14-14-14 (still a Scott's product). You know the stuff that used to say it lasted 9 months and now says 4 months. The spec sheet below shows at 60 degrees it feeds 4 -5 months; at 70 degrees, 3-4 months; 80 degrees 2-3 months; and 90 degrees 1 to 2 months. That's not on the label...you have to download the spec sheet.

I know Osomocote performs best when the temperature rises but I did not know that in heat you have to dramatically increase the frequency of application. It just says 4 months all over the bag, but not on the spec sheet.

I wonder how that affects the amount of fertilizer the plant gets..perhaps 20% at 60 degrees and 100% at 90 degrees or is it 100% at 60 and 500% at 90 degrees. Would ask the customer service but the last answer I got from these polite folks is that Miracle Gro is not for horticulturist or professionals. Just (gullible) home gardeners like me, I guess.

Also on the 14-14-14 spec sheet, really only 12-12-12 is available. What? It's right on the spec sheet below.

Here is a link that might be useful: spec sheet

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"What am I missing?"

Miracle-Gro® Liquid is labelled as 12-4-8, which means that it has 12 percent Nitrogen in the liquid concentrate. That is a decent amount of Nitrogen. Its Material Safety Data Sheet indicates that you are missing iron, manganese, and zinc in your Osmocote.


    Bookmark   November 27, 2011 at 10:12PM
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bugbite(z9a FL)

The Scotts rep wrote:

"The 937.5 ppm is for the concentrate, not diluted.

Thank you.

Ref # 989xxxx

Consumer Response Representative
The Scotts Company and Subsidiaries
14111 Scottslawn Road
Marysville, OH 43041

That has to be the diluted amount. I am asking them to confirm their responce.

re: "you are missing iron, manganese, and zinc in your Osmocote." Yes, and as a result, I am adding Ironite with the Osmocote.
Thanks for the reply,

    Bookmark   November 27, 2011 at 10:59PM
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ken_adrian Adrian MI cold Z5

you are missing a lot ...

first.. osmacote was developed for the greenhouse trade.. so some dude that has 10 million pots.. can apply a fertilizer.. in a very controlled atmosphere.. and only have to do it once or twice a season [or i should say. once before sale] ... IMHO.. it is not 'engineered' for the flower beds ...

though they 'market' it for home use.. it is wildly cost inefficient .... and really inappropriate ... again.. IMHO ...

next.. they offer it in a multitude of monthly formulas ... if i were to apply a 9 month feeding program.. up here in the garden in MI .. i would kill most of my plants ... as the soil is frozen more than 3 months a year ... so if you insist on using it outdoors .... you would need to by the right time period product ...

now .. i dont understand why a home gardener.. has such precise needs for fertilizer .... this is where you tell us.. you are running a greenhouse... though you do allude to being a home gardener ...

it would be much simpler for you to tell us what you are growing.. and what we might suggest for a fertilizer..

frankly.. in any kind of decent well maintained soil.. i am of the thought.. that you dont need any fertilizer ... you would be better off buying a good compost.. and adding a few inches to your soil every year .... and building your soil.. then worrying and wondering all about artificial fertilizers ...

your base problem .. in my mind.. is that you are getting overly wrapped up in the science .. but not seeing the bigger picture of home gardening ...

in my world.. you go to tractor supply.. buy a 12 dollar 40 pound bag of 12-12-12 .. and VERY LIGHTLY sprinkle it all over the garden .. if you are really intent on feeding your plants..

i just dont understand how you came up with needing parts per million of anything ... you are not seeing the trees thru the forest ...

so what are you growing.. how is it suffering that you think it needs to be fed .. ... give us some facts we can work with...

never forget.. they are not children.. most often.. they do not need to be fed.. nor educated... they are garden plants ...


ps: i also would not be fertilizing in the northern hemisphere in december ... its the wrong time of year... for plants that are in decline based on the position of the sun ... but that said.. i have never gardened in z9 .. so i would defer on that ...

    Bookmark   November 28, 2011 at 9:08AM
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"The Scotts rep wrote: "The 937.5 ppm is for the concentrate, not diluted." "

Well, there must be some kind of miscommunication here. They label the product as 12-4-8 which means it is 12 percent N by weight, and .12 x 1,000,000 = 120000 ppm.


    Bookmark   November 28, 2011 at 11:52AM
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bugbite(z9a FL)

ZM..You're right. I asked them to confirm, so I will see what they say. Thanks
I have conducted "HOME GARDENER" trials for a few seed companies. Normally that means planting seeds and caring for them as I have done for years.
Next year I am trialing 14 varieties of Marigolds for a seed developer from Southeast Asia. The marigolds were developed for very hot, humid climates. I pretested 2 varieties this year and the blooms were amazingly beautiful.
I normally just do what I have always done as a home gardener. But in a discussion with the seed company I saw pictures of fields of their marigolds which they grow for religious events, etc. I asked how they grow such amazing plants. They prep their soil a certain way and they fertilize 5 days a week at 500 PPM of nitrogen at a specific fertilizer ratio. Heck I never thought about PPM of nitrogen, but 5 day a week fertilizing intrigued me. I thought that I would like to try that approach on a side test to see how their approach performed in my garden. BUT I am a "home gardener" and have to deal with home garden issues..like I have a cat that licks water off plants everyday that I water, so I cannot use a liquid fertilizer. Before I came to that final reluctant conclusion I researched Miracle Gro and Jack's (Peter's). The Jack's people were extremely helpful! The Miracle Gro people said things like:
"The 937.5 ppm is for the concentrate, not diluted." A rep told me they were not scientists and suggested that I pick another company's product. They were very nice when they said it, but they said it.
At this second I have selected my fertilizer approach. It will be very similar to what I have done in the past.
Below is a fun article about fertilizer you might enjoy.
PS. I usually have other home gardeners also do their own test to get results in different gardening situations. There will be 12 other "home gardeners" in the "deep south" also participate in this "Home Gardener" trial. They will use their normal fertilizer strategies.

Here is a link that might be useful: fertilizer is not plant food

    Bookmark   November 28, 2011 at 7:37PM
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"...they fertilize 5 days a week at 500 PPM of nitrogen at a specific fertilizer ratio. "

That is a very weak combination of soluble fertilizer and water. Incidentally, that practice of combining irrigation and fertilization is sometimes referred to by the term "fertigation".

"I never thought about PPM of nitrogen, but 5 day a week fertilizing intrigued me. I thought that I would like to try that approach on a side test to see how their approach performed in my garden. BUT I am a "home gardener" and have to deal with home garden issues..like I have a cat that licks water off plants everyday that I water, so I cannot use a liquid fertilizer."

Yes you can. Miracle-Gro diluted to 500 ppm of N would be very weak, and harmless to your cat. City water or well water contains all manner of dilute minerals in the parts-per-million range, including traces of nitrogen. Even rain water has a little dissolved N, courtesy of lightning fixation of nitrogen from the air. Drinking rain water won't hurt you or your cat. When you are eating vegetables or fruits, you are ingesting some of the plant sap which contains, among other things, dissolved minerals from the soil that the plant has absorbed and hasn't used yet.

I could be wrong, but I don't think there is anything in Miracle-Gro (including the urea and the chelates) that doesn't already occur naturally in the soil. When you apply Miracle-Gro or similar soluble fertilizers, you are just replenishing components that are already there in the soil and in the plant. That's one of the things that Dan Gill covered in the link that you gave. Incidentally, I bookmarked that link. It is a well written article.


    Bookmark   November 28, 2011 at 11:50PM
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bugbite(z9a FL)

Great info ZM. Would that mean I cut it 240 to 1?
120000 ppm / 500 = 240.
ex: 1 oz to 1.875 gallons
That's about half the normal dose, I think...I have to check the label.
The folks I am working with say to cut that in half again at seedling stage.
I just recieved an email from the seed folks about another fertilizer method that is more "home gardener" friendly and not based on fertigation.
See another good article below (The info is probably "old news" to you, but interesting anyway.)

Here is a link that might be useful: Another good article

    Bookmark   November 29, 2011 at 12:45AM
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bugbite(z9a FL)

Update: I got a very nice call (not email) from Scott's. She said she made a mistake, that the PPM is 120,000 like you said ZM.
The interesting thing about the instructions on the bottle is that the bottle says to use 1/3 of a cap for two gallons, that's 2/3 of an oz. per 2 gallons. When I called twice to ask how many tablespoons that is (since a third of a cap is hard to calibrate) they said use 2 oz per 2 gallons.
If people use the formula on the bottle every 7 to 14 days, they are getting less than 400 ppm of nitrogen per application. Not much fertilizer.

About 10-10-10: When I started my analysis on fertilizer I called three feed stores and asked what fertilizer they recommend. I expected different answers, but they ALL three said 10-10-10.
I am currently testing 10-10-10 against Miracle Gro Shake'n Feed. The Miracle Gro Shake'n Feed section of plants (grown from seed this fall) is TWICE as big with twice the flowers. That fertilizer does work.

    Bookmark   November 29, 2011 at 1:52PM
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bugbite(z9a FL)

Sorry, I made a mistake. The ppm in the ferigation program used by the seed company for field flower production is 150 ppm, 5 days a week, like I said at the top, not 500 ppm that I stated later. That's very weak.
If a 12-0-0 liquid is 120,000 ppm nitrogen / 150 ppm (needed) = 800. "800 to 1" dilution is needed.
10 gal of water is 1280 oz /800 = 1.6 oz of fertilizer per 10 gallons. Is that correct?
(half of that rate is used at the seedling stage).
I might try a very small test with ferigation after all.
That's about a teaspoon in a gallon, 5 days a week.
Thanks for putting me on track,

    Bookmark   November 29, 2011 at 2:33PM
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Lots of good nitrogen fertilizer info in that article.

"Would that mean I cut it 240 to 1? 120000 ppm / 500 = 240.
ex: 1 oz to 1.875 gallons "

No, the 240 to 1 is on a mass basis. We need to convert that to a volume basis. Fertilizer labels, such as 12-4-8, refer to weight measures. And PPM usually refers to a weight basis as well.

However, when we dilute our plant nutrients, we almost always do it on a volume basis. Scott's liquid product is probably somewhat denser than water. A gallon contains 128 fluid ounces and 1.875 x 128 = 240, but we need to convert to a mass basis to get the PPM right.

We need the product density to convert volume to mass and vice versa. In other words, we need to know the specific gravity (density) of the liquid product. Its specific gravity is probably somewhat greater than 1. Water weighs about 8.3 pounds per gallon, so for the sake of argument, lets say that the liquid fertilizer weighs about 9 pounds per gallon. The label indicates it is 12% N, so 9 x .12 = 1.08 lbs N per gallon. Let's say you want to add 1 oz of LiquaFeed to G gallons of water and wind up with 500 PPM of nitrogen in the solution. That ounce contains 1/128 gal x 9 lb LiquaFeed/gal x .12 lb N / lb LF = 1.08/128 lb N = .0084375 lb N. We add that to G gallons of water to get .0005 lb N/ lb water.

.0084375 lb N / ( G gallons x 8.3 lb/gal ) = .0005 N / lb water

Solving that equation for G, G= .0084357 / (8.3 x .0005)
Hence G is about 2.03 gallons. That's not too far from your 1.875 gallons, but it does take into account the fact that the PPM is on a weight basis. For a more accurate number, you would use the actual weight of one gallon of LiquaFeed, instead of the 9 lb/gal estimate that was used above. And in the calculations above, we neglected the amount of water in the 1 ounce of LiquaFeed. To be really exact, we would take that into account in the algebra. And we would use a more exact number than 8.3 pounds per gallon of water. But we are in the right neighborhood for the dilution if you plan to use Miracle-Gro LiquaFeed. You might want to check my math. I am a little rusty in that area. Other areas too, but we won't go into that.

In your first message, you said "I contacted Miracle Gro (Scotts) about the PPM of Nitrogen in their Liquid fertilizer." Are you talking about their LiquaFeed product? I think that is probably the one that the MSDS I linked to referred to. Their LiquaFeed system is convenient, but not cost effective in my opinion.

If you go down to the bottom of the page I just linked to, you will see a hose-end feeder that you simply screw a jar of solid Miracle-Gro into. I am not recommending that hose-end feeder (notice that it got low user ratings), but I am recommending the use of solid Miracle-Gro products as giving you more "bang for the buck". Also, the solid Miracle-Gro products (outdoors I use Miracle-Gro Tomato Food (18-18-21) for its higher magnesium content) also contain the trace element copper. The LiquFeed product apparently lacks both magnesium and copper.

If you have copper plumbing, you may not need the copper, and some water supplies may already have some magnesium. But in our rural environment I need both, and my zinnias develop boron deficiency symptoms unless I add a trace of boron (in the form of boric acid) to the nutrient mix. I also grow zinnias and other plants indoors, which requires that I use urea-free nutrients that contain all of the trace elements, including boron and molybdenum and I have to supply calcium indoors -- I use calcium nitrate. Plants actually need a fair amount of calcium.

Incidentally, although plants can live without silicon, they actually benefit from it in several ways. Rice growers usually include a considerable amount of soluble silicon in their fertilizers for stem strength. I use liquid potassium silicate concentrate to provide soluble silicon.


    Bookmark   November 29, 2011 at 2:59PM
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I didn't see your last two messages until after I just posted above. Same principles apply, if with different target numbers. A daily weak fertigation is a pretty good idea, particularly if you do it as a foliar feeding with runoff drench for the roots.

A fast growing plant can deplete the nutrients in the tiny zones just around the root hairs, even though there are nutrients not too far from them, depending on diffusion to move them closer. Simultaneous daily foliar feeding could solve that, by keeping some nutrients in intimate contact with the leaves.

I think there is real merit in maintaining continuous uninterrupted nutrition for maximum plant growth. A daily weak foliar fertigation will keep your plants clean, too, and maybe wash off a few pests.


    Bookmark   November 29, 2011 at 3:19PM
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bugbite(z9a FL)

Great analysis! Extremely helpful. Thanks ZenMan!
I am now curious about the weight of the fertilizer and will pour a pint and weigh it. The fertilizer I am referring to is:
Miracle-Gro 1001501 All Purpose Liquid Plant Food - 32 oz
Sorry I forgot how to embed a link here and wanted to use the link below. You have inspired me to look into ferigation.
If I proceed with ferigation on a complete garden level I will just order the fertilizer from JR Peter's which is the former Peter's, now sold under the Jack's name. You tell them what formula you want, the PPM you want and which siphon you will use then they will tell you what to use and how much per gallon. Crystal at JR Peter's is extremely helpful.
The professional 25# bags are cost effective; the shipping for 25# is not cheap. The biggest issue will be to get a good siphon for a decent price.
Whether you are interested or not in fertilizer this is a great site to look around.
Thanks again,

Here is a link that might be useful: Jack's (actually the former Peter's) Professional fertilizer

    Bookmark   November 29, 2011 at 6:38PM
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Thanks much for the Jack Peters link. I used their site to search for a retailer, and there is one about 22 miles from me, which could be quite convenient since we frequently shop that area. I will contact that retailer to get some price quotes. I may be able to get some better nutrients in quantity at affordable prices from them.

I did some syphon feeding this last Summer through a fabric soaker hose. That worked reasonably well, but I used a cheap translucent plastic laundry hamper to hold the stock solution and the sunlight destroyed the plastic container after a few months. It became so brittle that just touching it would break it. I shattered it and disposed of the pieces in the trash. I'll use a more durable container next year.

I also use an electric powered sprayer that has a seven-gallon tank on a wheeled dolly with a 50-foot hose. It is much more convenient to use than the hose-end sprayer I used to use, and its hose is easier to drag than a garden hose. And since the spray is pre-diluted in the tank, you know exactly what concentration you are spraying. Sometimes my hose-end sprayer would clog and you would be spraying water and washing off the spray you had just applied. That can't happen with my electric sprayer.

Your southeast Asia seed developer's successful methods have inspired me to step up my foliar feeding/fertigation game next year. I really like the idea of daily or nearly daily weak solution feedings. A siphon-fed lawn sprinkler system could completely automate the daily feedings. That is something for me to think about.


    Bookmark   November 29, 2011 at 11:16PM
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bugbite(z9a FL)

In like your electric power sprayer approach but think I'll take the lazy way out and use a Hozon siphon in a 5 gallon pale.
Hozon has been used for years by professionals and serious home gardeners, but on one site that sells Hozon some people have experienced issues. I asked Crystal at JP Peters about those comments. She said that it could be the brand of water soluble fertilizer; some don't dissolve as well and clog equipment.
Now get this...she said she would take one home before she shipped it to me and test it and make sure it is operating properly...Now THAT is great customer service. I told her that their customer service is far better than the competitors. She said she hears that alot.
I plan to order Jack's Bloom Buster and use it in phase 2 once the plant shows it's first blooms. In phase 1, during initial plant growth and through pincing, I will use the water soluble fertilizer with higher nitrogen that I already have.
Anyway I will stop posting and get on with this project. Thanks for all your help.

    Bookmark   November 30, 2011 at 7:52PM
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Hozons are a brand name of proportioners using the venturi effect. Basically at normal rates they will dilute the solution to 1/12th of it's previous concentration(dilution). So you need to start with the proper concentration stronger than you want on the plant, because it'll be diluted again when it passes through the hozon. As the length of the hose increases, you'll find the hozon will proportion at a different rate it can also vary with water pressure. Too small sprinkler heads on your water breaker will also cause a back pressure and can push the ball valve in the proportioner to stop the irrigation flow. Ditto kinks or constrictions in the hose or clogged sprinkler holes. They're tricky sometimes but that's where the 'problems' usually lay with Hozons and folks just blame the device instead. I've used them for many years.

I don't buy miracle grow for constant irrigation, but buy Peters a water soluable formulation for professionals. It comes by the 25# bag and your ag supply store can probably get it.

Constant feeds with very weak dilutions work great, but if you are doing it in an outside situation, you have got to know there will be more wasted salts than the plant will ever use and that even in g'house situations, a regular 'wash out' of the soil or matrix is recommended so you won't have plants damaged by high salts build-up.

As zenman says, there are different formulations of osmocote for different situations. They do respond differently in different heats, but think about it. When a plant is in a hot or windy situation they use more water and therefore with each irrigation take up a similarly increased salt load. Once it's applied, it's applied! You can't take it back out of the soil. Growers will hit their pots with it carefully at beginning of active growth, and then just touch up with liquids to bring the matrix up to the level necessary as the osmocote depletes. You cannot control the rate of take up once it's on. It's going to be up to how actively the plant is growing. Be careful with over fertilisation.........I honestly think giving too much is worse than too little. It is salt afterall and the plants can get toxic. Also too much N will be at the expense of your blooms! and can produce weak stems as well.

    Bookmark   December 20, 2011 at 3:14PM
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bugbite(z9a FL)

Great info. I often see the dilution ratio 1 to 16, as in the link below. I think somewhere I even saw 1 to 19. Away your info was excellent and I appreciate the info you provided.
I thought I might have hit on a solution that would be a quick, cheap way out, since I have over 12 pounds of the stuff.
It is the micracle gro "shake n' feed" time release fertizer. I did an experiment with some cosmos I planted from seed in September. I used 10-10-10 and the MG "shake n' feed" on half each. The MG really made the plants grow. But I noticed this week that the leaves are burning on the MG side and not the 10-10-10 side. The 10-10-10 side doesn't seem to be doing much. Plants half the size; half the blooms.
I did carefully follow the application instructions so I don't think I over dosed the plants. And this is fall when the slow release should really release slow.
Guess Hozon might be a safer way.
Thanks for your input.

Here is a link that might be useful: Hozon

    Bookmark   December 20, 2011 at 4:01PM
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Bugbite...you certainly take your trials seriously. Here is one thing I'll throw out. I'm a grower and just retired after being in the business for 23 years. I trialed most of my new introductions the year previous to offering them to the market. It's a real eye opener because seed companies tend to lay their emphasis on the desireable traits of their product to the exclusion of the negative traits. Were this not so, then the universities and plant brokers would not have trial gardens to put them to the test and just accept what the seedsmen say.

When you are asked to do a home trial, I would assume the seedsmen are asking you to do just what I did, and that is grow them under 'average' conditions......because they want to know before the fact how their product will produce for their sales target. You are not in a contest with other people who may also trial for the seedsmen. You give them their money's worth by growing the plants the way most homeowners grow them. Otherwise the information is really not useful to them. It gives a tainted impression of how their product will perform to the masses.

    Bookmark   December 21, 2011 at 11:13AM
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bugbite(z9a FL)

Very true. There will be 14 home gardeners, plus me in this trial. I hope no one will compete against another in this trial. I will ask all to do what they choose regarding growing methods. Great to hear your words of wisdom. Your experience is valued.

    Bookmark   December 21, 2011 at 5:36PM
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