Injecting fertilizer into the substrate?

[HarryL]

Like the title suggests, does anyone have practical experience in injecting macro/micro to under the substrate so that before it leaks to the water column, perhaps gives the roots a chance to absorb when its somewhat concentrated, and replenish the soil maybe.

I've seen some older threads on other forums that people generally just aren't bothered with this idea but in some places it still seems like a common practice. One argument was that it will be in the water column sooner than you think, but what if my substrate are relatively thick? And isn't this very similar to burying a root tab down there? In my mind, it'd be easier for me to dose in substrate with a super long needle than to try to bury a big capsule in the soil hoping it doesn't float up.

 

[gnatster]

There is a thread here

 

[HarryL]

There is a thread here

That's quite different, where it's injecting soil under inert substrate instead of ferts

 

[Naturescapes_Rocco]

I guess my question is, what is the reasoning for not just dosing the water column? Aquatic plants can take nutrients in through leaf and stem tissue just as well as root intake.

 

[HarryL]

I guess my question is, what is the reasoning for not just dosing the water column? Aquatic plants can take nutrients in through leaf and stem tissue just as well as root intake.

I’m thinking from the idea that it’s good to use root tabs or add some new soil once the soil is depleted of nutrients. Would you simply not use any root tabs either and just increase the weekly dosage after the soil doesn’t have much nutrient?

 

[Naturescapes_Rocco]

I’m thinking from the idea that it’s good to use root tabs or add some new soil once the soil is depleted of nutrients. Would you simply not use any root tabs either and just increase the weekly dosage after the soil doesn’t have much nutrient?

That's definitely one way to do it!
For reference, this tank has completely inert substrate with no root tabs or aquasoil. Just inert sand and liquid/dry fert dosing!

You can also stick some root tabs in with tweezers. That's what I'd recommend at the least -- some capsules of nutrients, pushed in towards the roots of your plants.

Injecting liquid ferts doesn't work very well, mainly because it really does just leak into the water column over time, and you might as well dose the water column then!

 

[HarryL]

That's definitely one way to do it!
For reference, this tank has completely inert substrate with no root tabs or aquasoil. Just inert sand and liquid/dry fert dosing!

You can also stick some root tabs in with tweezers. That's what I'd recommend at the least -- some capsules of nutrients, pushed in towards the roots of your plants.

Injecting liquid ferts doesn't work very well, mainly because it really does just leak into the water column over time, and you might as well dose the water column then!

That's good to know! And that tank is really beautiful.

How would you adjust your dosing from fresh soil to 6 months later? I'm beginning to think that I'm not dosing enough and my plants are starving a little. The tank is a year old now and issues have been showing up, like poorer stem plant growth(ludwigia and rotala mainly) and more algae. I'm def not cleaning the detritus enough and that contributes a lot to the algae.

 

[techman81]

When aquasoil becomes nutrient depleted, you can re-seed it with fresh aquasoil. @Dennis Wong talks about it here.

 

[Pepere]

I have under gravel Filter plates with a 3/4 inch thick base of 1 part aquasoil, 1 part Safe T Sorb, 1 part Activated carbon in mesh bags covering the plates and capped with 2 inches of Black Diamond Blasting sand.

My thought is that the continual flow of water column ferts over and through this base replenishes nutrients in it.

The plant roots do tend to enter into the mesh bags more so than the BDBS .

Is it doing anything more than just circulating water column ferts over and through the roots via ugf flow?

I have no idea.

But I am happy with the plant growth and my results..

 

[HarryL]

When aquasoil becomes nutrient depleted, you can re-seed it with fresh aquasoil. @Dennis Wong talks about it here.

Yes I’m aware of that but that’s also a bit more work and less convenient than doing ferts, that’s why I’m asking if injecting could be another way to deal with it

 

[Naturescapes_Rocco]

It's certainly not a popular or recommended method. For me personally I would (and do) just fertilize the water column.
If you're curious, give it a try and write a post about your findings!
I tried it once but I think my syringe needle was too small. The second I injected the liquid, it bubbled up through the sand. Many others say it will just end up in the water column, which I think could happen. But give it a try and report your findings.

 

[HarryL]

My thought is that the continual flow of water column ferts over and through this base replenishes nutrients in it.

I definitely think that gives the roots access to a lot more nutrients, but yeah I don't know for sure

 

[Ernesto]

Like the title suggests, does anyone have practical experience in injecting macro/micro to under the substrate

This guy was injecting macros under the sand. Found it an interesting concept, but didn´t try it out myself yet.

Diffusionsdüngung im Sand/Soilalternative

Hallo zusammen, Sand als Substrat fand ich aus verschiedenen Gründen schon ziemlich überzeugend und man wird sich fragen, was soll denn das mit der Diffusionsdüngung im Sand? Das ist erst mal nicht mehr als das strömungslose Diffundieren von Nährstofffen in den Sand. Passiert sowieso immer...

www-flowgrow-de.translate.goog

edit
link via google sucks on safari,
this directly

 

[snowballs99]

Fairly easy to test the theory isn't it?

Take a bush of stems.
Inject only on 1 side of the stems.

1 side should grow faster/more robust than the other over a month.

If after 1 month they both look the same, we can pretty much conclude it just all leeched I to the water column anyways.

 

[Ernesto]

no need for test-it will diffuse anyways.
interesting is, how fast it will leech, and if this would enhance the substrate, rootgrowth and regrowth after pruning (eg with inert sand with a specific grain size)

 

[HarryL]

Either way I'm still quite interested in doing it. I will later attempt this with my smaller 11 gallon(has old aqua soil) and grow two groups of maybe Ludwigia Arcuata to see how they respond. Hopefully I can come and give an update earlier next year.