# The Osmocote thread



## Michael

Many people are using Osmocote in their planted aquaria, but there does not seem to be one place where information about this practice can be found. I hope that this thread will become that place.

First of all, Osmocote is a brand name for an encapsulated time-release fertilizer sold for use with terrestrial plants. The name comes from the word osmosis. When the capsules (or granules) and soil surrounding them are wet, the fertilizer inside moves through pores in the capsule by osmotic pressure into the soil. The product has been around for at least 35 years. I believe it was originally protected by patent, but this has expired. Now there are competing brands that function in the same way. Our discussion will include those too.

I invite everyone who has used Osmocote in an aquarium to post their experiences in this thread. Please make the information as specific as possible, so that we can make meaningful comparisons. To that end, I suggest the following format:

*General tank parameters.* What size tank, what type of lighting, what type of substrate, CO2 or not, what type of filtration or water circulation?

*What kind of Osmocote did you use?* There are several different formulations of the product on the market. If you used a different brand, please say so. For this discussion, we only want information on encapsulated time-release fertilizers intended for terrestrial plants.

*How did you use it?* Did you mix it with substrate when setting up the tank? Did you add it to existing substrate in an established tank? If so, did you put it in gelatin capsules, roll it into clay balls, freeze it into tiny ice cubes, or put each granule into the substrate with forceps one by one? (If the latter, you may have too much time on your hands, lol.) I assume that no one just throws the stuff into the aquarium, but correct me if I am wrong!

*How much did you use?* This is where the information usually becomes quite vague. I suggest we try to use a volume measurement of the Osmocote per a given area of substrate. Some examples: "I froze 1/4 teaspoon of Osmocote into each ice cube, then put one cube into the substrate about every six inches, for a total of 9 cubes in about 2 square feet of substrate." Or, "I mixed 20 ml of Osmocote in the substrate and spread it on the bottom of my 10 gallon." (10" x 20" = 200 sq. in. or 1.4 sq. ft.).

You may not remember, or you may not have measured, but please give a reasonable description. This can be as simple as, "I sprinkled a little on the bottom of the tank so that I could see lots of glass between the granules before I added the substrate."

*Effect on plants?* What species did you grow, and how did each perform? Did they grow well, or did they die? Which ones showed accelerated growth, and which ones stayed the same?

*Effect on fauna?* Did it kill the fish? Did the fish do fine, but the shrimp jumped out of the tank? Fish and invertebrates didn't seem to notice?

*Any other problems or advantages?* Algae bloom? Granules escaping from the substrate? Was it easy or difficult to use? How long did it last?

I'm sure I haven't thought of everything, but that's enough for now. And if you are wondering, I have never used Osmocote in an aquarium, but I have used it on terrestrial plants, and to fertilize water lilies and other aquatic plants in ponds. I like it for those purposes.

Thanks in advance for any information!


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## NeonFlux

Hi Micheal, during my experience with it, I did not experience any fish deaths, but I have not tried any with dwarf shrimp yet.

I am currently using Osmocote Plus DIY root tabs for my 60 Gallon High Tech. I have timed T5 lights that go on and off during certain times, and timed co2. I use Aquasoil Amazonia 2 as my substrate (it is getting old and the nutrients are finally waning, so that's why I'm using Osmocote) and I use a Eheim 2215 canister filter.

I substitute any brand name root tabs with Osmocote Plus filled in gel sized 00 capsules. They are definitely great for heavy root feeders such as swords and crypts. All plants could benefit from it, in my opinion. So if you want to use it, you have to make sure it is deep within the substrate, so it isn't exposed out of the aquarium; if that were to happen, you may experience some algae. So it's a bit of gamble/risk, you have to make sure it doesn't completely get out of the substrate in large amounts. If it does, it will leech off nutrients slowly, and cause some algae issues if left unnoticed; other than that, the plants will grow well in the long run. The root tabs are placed 3 square inches apart, that's how I do it.


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## Michael

Thanks, Neon!

About how much does a 00 gelatin capsule hold?


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## NeonFlux

You're welcome.

I'd say a good 2 pinch would probably be enough fill one.


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## farrenator

*General tank parameters.* 
75 gallon
4 x 54w T5ho - 2 bulbs on for 3 hours, 4 bulbs on 4 hours, 2 bulbs on 3 hours
Eco Complete
Pressurized CO2 comes on 1 hour before lights on, off at 1 hour before lights off
Cascade canister filter + Tunze powerhead - plenty of flow.
Dose PPS Pro

*What kind of Osmocote did you use?* 
Osmocote® Flower & Vegetable Smart-Release® Plant Food

*How did you use it?*
Buried it in substrate in 00 size gel caps after the tank was set up an running for over a year. I planted one gel cap under each Amazon Sword plant that was exhibiting slow/stunted growth and yellowish leaves. Sword plants have been in the aquarium for over a year and have highly developed root system. Planted one gel cap under a bunch of vals that were added to tank 2 weeks ago.

*Effect on plants?* 
One amazon sword plant has absolutely taken off. Leaves have doubled in size and have developed nice green coloring as opposed to before when color was definitely green but had more yellow in it. The other sword plant is showing minimal changes. It looks healthier - greener with more leaves - but has not taken off like the previous sword.

I see no change in vals. Vals have only been in the aquarium for about 2 weeks so they are probably still developing a root system. They look healthy and deep green color.

*Effect on fauna?* 
No inverts except for invasion of ramshorn snails. These guys aren't effected. Cardinal tetras, rummynose tetras, black neons, kuhli loaches and rainbow fish are unaffected.

*Any other problems or advantages?* Algae bloom? Granules escaping from the substrate? Was it easy or difficult to use? How long did it last?

No algae blooms. Granules do not escape the substrate unless I dig them up. They are easy to see and easy to re-bury.

I occassionaly test for NO3 and Phosphate and have notice no substantial changes in these parameters. Gel caps have been under the swords for about a month and under the vals for about 2 weeks.

Very easy to use.

Not sure how long they will last but I imagine 2 months or so.


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## tulip55555

I was searching for info on dosing Osmocote Plus and found this. You are absolutely right about info on dosing being vague. It seems this thread has gone unnoticed for a week or so, so I just wanted to bump it back up. Looking forward to more input.


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## Michael

Yes, I hoped it would bring all the Osmocoters (Osmocotists? Osmocoteurs?) out of the substrate, but it seems they are a secretive lot.

I can report one modest experiment of my own. The centerpiece C. wendtii in my year old Walstad tank was looking tired--not much growth and loosing more old leaves than normal. So I made 3 Osmocubes with 1/8 teaspoon of granules in inch long ice cubes. I pushed them into the soil about 3" apart on 3 sides of the plant. The fourth side is blocked by driftwood.

That was 5 weeks ago. The plant looks better, more red, more new leaves, and is losing old leaves more slowly. It is not a big change, but an improvement. There were no problems afterward. But when I was putting the cubes in, I had to move quickly or the melting ice would drop granules. When I do this again, I think I will roll the granules into small clay balls and let them dry a little before inserting them into the substrate.

--Michael


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## frroK

I am trying to grow some dwarf hairgrass emersed in sunlight. I had a little plant set up for about two weeks with nothing. Plant didn't want to grow and nothing was happening. I have it in dirt(MGOCPM) with a fine cap. Last week I added some osmocote and all of the sudden it took off! It finally started to show some life. I have yet to try it in any of my dirt tanks. They are fairly new, I doubt I'm lacking nutrients. But I'm tempted.


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## mrkookm

The method works, but it has to be done in moderation. A few years back when I was doing this- before it became this 'new trend'  I figured out for my tanks .4gr in OO capsules worked well. DO NOT OVER APPLY IT or you will end up with problems, and I'm not talking algae. Overall plant health will degrade and you sub will essentially become toxic.

If you really want to see things rock you grind up 2 or 3 grains in addition to the solid within the tab and watch your plants transform. If you say prepare and entire tab of crushed grain your plants will become ridiculously large and problems will likely arise if you apply too much. .3g ground per OO cap or whatever size or binder method works well.

When using any tab most will find that you will need to adjust your NPK dosing. I still dosed my own mix of micros, but at a much lower ppm rate. Micros is very important in overall plant health and color- its not just an FE thing.

Substrate seen in pic is Turface Proleague and growing healthy plants better than most ADA sub.

The diameter on this was 6in


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## BruceF

This is probably a little off topic but I have used jobe’s plant spikes ( the ones for ferns) a few times. They are much easier to add to an existing substrate. Cut them up, bury them kind of thing.


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## Aquaticz

OK _ I'll ask .......How far apart do you suggest the 00 cap be from each other >


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## mrkookm

I liked 4x4 uncrushed - 6x6 crushed


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## Michael

Thanks for all three of the last posts!

mrkookm, when you were giving amounts, were they in grams? That is g or gr = grams? Also, how many tabs did you use per tank, or per plant?

BruceF, do you have an analysis (NPK) of the Jobe's plant spikes? How many did you use?


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## BruceF

The Fern spikes are 10 2 6. I would use maybe half a stick in a 10g. I just guess-timate these things. Depends on how many hungry roots there are etc.


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## Austin.b

How many would you advise in a 10G?


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## Diana K

How shallow a substrate is OK? 
Does it make a difference if the substrate is high CEC? Will this grab the fertilizers before they escape into the water? (Assume the placement is on the bottom of the tank)
If you are using sand (no CEC, more water movement) would you use less overall, perhaps more capsules better spread out, but less in each capsule? 
If you are starting with new cuttings (no roots yet) is there any benefit to starting the Osmocote at the same time? (build up a reserve in the high CEC substrate?)
Does the clay ball or the 00 capsule slow the release compared to ice cubes (which melts very quickly, of course, leaving bare Osmocote in the substrate)


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## rod

I have used Osmocote in my 75gal. 3 1/2" of Laterite and gravel mixed for substrate. I put it in clay balls, what a mess. They were easy to make and put in, but every time I touched the substrate the clay would be released. I must say however, it worked fantastic for the Lotus but that was the only one I saw any difference in. What are the 00capsule that is being talked about?


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## Diana K

00 capsules are empty pill things. When you get some powdered medicine (like herbs) it is often in a clear gel sort of capsule. These are available empty, and you fill them with Osmocote, or other things. 00 (zero zero) is the size. They melt in water, leaving the Osmocote deep under the substrate.


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## rod

Thanks Diana


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## Michael

I'm glad to see more activity in this thread.

On the subject of Osmocote with high CEC substrates, I'll share my observations of soil substrate with high CEC cap and mixtures of the two. A tip some time ago from Phil Edwards was to mix the mineralized topsoil 50/50 with Turface, then cap with Turface or an inert gravel. I have tried this in one 40 gallon and several smaller tanks, and it works very well.

I think the reason is exactly as Diana describes: the high CEC Turface grabs the ammonia and other nutrients released by newly submerged soil and sequesters it in the substrate instead of releasing it into the water column. This helps prevent algae blooms in new tanks, but still makes the nutrients available to plant roots as they grow into the substrate. It seems likely to work the same way with Osmocote.


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## wwh2694

I had used the Osmocote plus put it on 00 gels caps.

My inverts tank: ADA 60h with flourite subs.
I put about 8 caps of these 00 gels caps full of osmocote plant growth was crazy. But when i have to pull some stems plants i see alot of those fertz laying around. My inverts look ok not great from time to time i see dead shrimp. Oh and for the snail i see alot of dead snail after i used this specially the burrowing snails they are gone and died. So this tank was snail free now. In the end i finally removed the substrate and changed it to fluval stratum shrimp subs. Didnt used it anymore.

My big tank: ADA 120h with eco complete subs.
I have used alot of these probably more than 20 caps at one time. It grew like crazy for several months now couldnt figure it out why my plants are dying???? Im thingking its the later effect of this osmocote. Well now still figuring out whats wrong with this tanks. Lots of hair algae, GDA plants not growing fast. I have done several water changes and after the water change plants started to look great until several days again they will look bad???. I have been doing EI on this tank and i have read on Tom barr that if u do a water change and the plants look great after wards and its the co2 is the problem. Well now still adjusting my co2 hope i wont kill my fish. Plants wise there growing slowly now. I had never had this problem before i put the osmocote probably i put to much of it. Snails, i see moderate amt of the burrowing snails around now, but after i used the osmocote the no. of snails drecreased alot. Still dont know if its the osmocote. But again after water change i see them comming out.

I have never used the osmocote for several months now but from time to time when i pull the stem plants i see some of it. Now will i use it again? Probably but in low amt. Will i used it on shrimp tanks? That will be No. Hope this helps


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## Basic

I would like to try the osmocote. Does anyone know where I can get the 00 gel capsules?


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## wwh2694

I got alot. U can get them at ebay.


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## herns

Geat info thread about Osmocote plus!


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## DaTrueDave

Basic said:


> I would like to try the osmocote. Does anyone know where I can get the 00 gel capsules?


This is what I used: Now Foods, Vcaps '00' Empty http://www.amazon.com/gp/product/B000OSQS4U/


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## herns

Now that Osmocote plus is discontinued this year, some are using without the "Plus" and even sell them. 

Sent from HTC One device using Tapatalk2


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## Window7

I still have around 10 big bottle of it. Good thing I I bought in bulk


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## herns

Window7 said:


> I still have around 10 big bottle of it. Good thing I I bought in bulk


Good.

I think the 50lbs bag is equivalent to 11 jugs. I got mine on Amazon for $134 shipped.

Sent from HTC One device using Tapatalk2


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## king kong

Just started with the gel caps. Works well but I did not break up prills.


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## king kong

Actually using a product called nutricoat. A little different but basicaly the same formula but not grinding them up before I put in gel caps.


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## Wphan

I was lucky to find a couple jugs on a website after the company discontinued them.


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## iziko

Nice Thread !


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## Pinto

Lowes is selling Osmocote 8-lbs Plus Flower and Vegetable Food Granules (15-9-12). Is this the same as the one they discontinued?
http://www.lowes.com/pd_153108-446-...153108&pl=1&currentURL=?Ntt=153108&facetInfo=


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## maboleth

I have a bunch of osmocote balls. I tried burying them but they always manage to find a way out when I plant the stems. Always having 3-4 on the ground. It's quite annoying.

How do you plant them in established tanks? Did anyone tried putting them in old women's stockings or any kind of mesh?


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## AaronT

maboleth said:


> I have a bunch of osmocote balls. I tried burying them but they always manage to find a way out when I plant the stems. Always having 3-4 on the ground. It's quite annoying.
> 
> How do you plant them in established tanks? Did anyone tried putting them in old women's stockings or any kind of mesh?


I think most folks are using empty gel caps like these.


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## maboleth

Thanks Aaron! Great stuff, I haven't seen them in shops nearby, but will search.


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## AaronT

maboleth said:


> Thanks Aaron! Great stuff, I haven't seen them in shops nearby, but will search.


I've seen them in the health food shops locally in the supplements section. They're pretty cheap on Amazon or Ebay too.


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## maboleth

I was about to buy them on Amazon, from your link, but then I got the idea to just dump them in the ice cube tray, pour some water and now I have thin osmocote tablets.  Will see how fast they melt. I guess I'll have plenty of time to put them deep in the gravel.


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## Michael

Another technique is to mix the osmocote with damp potter's clay, then roll the mixture in little balls and let them dry. Then push them into the substrate with forceps or a stick.


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## marrow

The ice method works well and you can even freeze it in thin sheets that are easy to slice/slide under the substrate. There is no need to make a whole ice cube. halves or quarter thickness ones are much easier to slide under the substrate without bothering established plants.


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## maboleth

marrow said:


> The ice method works well and you can even freeze it in thin sheets that are easy to slice/slide under the substrate. There is no need to make a whole ice cube. halves or quarter thickness ones are much easier to slide under the substrate without bothering established plants.


That's what I did, half the cube was enough, about 1cm thickness. However, I had to be quite fast in inserting them under the substrate, they melted very easily.


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## fattytuna

Hello, I am a new member from Australia. I looked at Bunnings Warehouse online catalogue and noticed that they had a product named "Water Gardens and Aquatic Plants". It comes in a 250g packet of 50 tabs (don't have to make your own) and is advertised as being safe for fish. The N-P-K ratio is 14-3.5-9.1 and it has "added trace elements", however it was not specified which ones on the site.

What do you guys think?

Edit: on another site is says that Iron and Magnesium is added. It says that it is "developed to feed water gardens, pond plants and plants kept in fish tanks."


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## Michael

It looks good. Depending on the size of the tabs, you may need to cut them into smaller pieces for aquarium use. I haven't seen this product in the USA, try it and tell us how it works!


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## Tugg

I found this on them. They look to be fine, and less work since you don't need to pack gel caps.
http://www.fishforums.net/index.php?/topic/420080-osmocote-root-tabs/


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## thepoweranga

Hey guys very interesting thread. I was just wondering if anybody has used this specific osmocote? After reading this thread it jumped out at me in the supermarket this arvo. Nobody mentioned this one specifically though and don't want to poison all my fish.

Not sure what I'm looking for as far as what's safe and what's not when it comes to osmocote. Any help would be great!
















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## Michael

The analysis isn't that different than other forms of Osmocote, except that it is heavier on the nitrogen. This is appropriate for indoor foliage plants. Use it sparingly, and it will probably be fine in an aquarium.


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## Jeffh

Is this still a thing we can use in planted aquariums?


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## mistergreen

Jeffh said:


> Is this still a thing we can use in planted aquariums?


You have to bury it in the substrate. Use sparingly.


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## Michael

Diana Walstad suggests using Job's Plant Spikes. I've tried them and they work. The big advantage is they are MUCH easier to use, just push them into the substrate with forceps. As they come in the package they are about 2" long. I cut them in half and use 3 or 4 pieces for a large plant like a _Nymphaea_ or _Echinodorus_


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