Greensand

[hydrophyte]

Hi Everybody, I have been doing a bit of research on slow-release nutrient sources and I wonder about the use of greensand as an amendment to a MTS-type substrate.

With a Google search I found just a handful of references to the use of greensand in planted tanks. Several of these warned that if immersed in water greensand will dump all of its nutrients quickly and cause trouble.

I also searched for descriptions of use in water gardening/ponds and found nothing. I wonder if greensand might be unsuitable for this kind of application(?). Does anybody have any opinions about this?

[dbosman@msu.edu]

Asking us if we have opinions on anything is opening the door to ...

You ask an interesting question. The glauconite in greensand should release iron as well as the potash. Greensand is supposed to not be soluble in water so I don't understand how the nutrients would dump.

Grad Student alert. Possible thesis project for aquatic, hydroponic, and pond amendment use.

[hydrophyte]

I am prepared to sift through as many opinions, informed and otherwise, as I can get.

Well it seems like a good thing to use. I have encountered few other slow-release sources for K. Do you have any other ideas for rock-based or organic options for potassium?

If you search here on TPT there is apparently just one member who reports using it as amendment with his soil substrate. It looks as though he has had good results, although you have to guess that the soil itself provided a robust reserve of nutrients.