Aquaponics - Shell grit seed raising

It seems like I've been trying for ages to find a decent method to raise seedlings from seeds.

My preferred method would be to just throw them all over the place and see what happens, but I suspect the clay ball media allows seeds to fall way down into it. It's possible that with the normal vibrations of city life, that the seeds fall all the way down into the water and then sink to the bottom and rot.

One problem with raising seeds in potting mix is that you do a lot of damage to the roots when you wash them before transplanting them into the aquaponics system.

I add shell grit to the system as a pH adjuster. The nitrifying bacteria tend to move the system toward the acid side, and the shell grit brings the pH back into line (approx pH 7.0).

So I figured it might be a good idea to raise my seedlings in shellgrit.

I started with a food container, and drilled a few holes around the base.

Then added the mesh from a stainless steel sieve, and filled it with shell grit.

Shell grit can be bought where ever you might buy chicken feed, as they sell it to people who have chickens. Chickens eat it and it helps make their eggshells strong.

I chose a space close to the water inlet in the growbed to bury it so the water flowing through would have high levels of dissolved oxygen. I figured this might be important as the flow through the tightly packed shell grit would be slow.

I buried it at a depth so the water level just reached the shell grit. The water "wicks" up through the shell grit so it stays moist.

I also added a lid in the form of another food container.











I'm not sure if the lid is needed, but a lot of store bought seed raising trays have lids so I thought I'd add one. It probably isn't required because I'd guess the lids are used to keep the moisture in, but with water always wicking up from the bottom...

Who knows.

I have no idea if this will work, but as always, I'll let you know one way or the other.


120 Things in 20 years - My ribs hurt.