Using soil, river sand, M-sand, etc. as grow bed media

[NARDC.in]

Using soil, river sand, M-sand, etc. in Aquaponics grow bed along with or without gravel.  Has anyone done this before?   

I understand clogging is one big issue.  We have these available in plenty, almost at no cost and would like to use them in one of our new octagonal grow beds.  Lining and plumbing work is yet to be done.  I thought of asking this before filling in the media.  

What are the pros and cons.  Any pictures? 

Thank you and appreciate your valuable tips.

[Sahib Punjabi]

Namaste Nanniode,

I have using soil etc in Aquaponics for some time, actually well before I wrote a blog in December 2012 (see the link below). My research has now led me to growing much more economically and sustainably with Aquaponics as the base - my Aquavermiponics systems (initial blog in May 2012 on my website). I now have four such Hybrid Aquaponics Systems - one that I recently set out for tomatoes - and other vine crops plus root vegetables. I also have one side by side with my DWC Aquaponics system - Excellent growth as noted in my recent Youtube video (I posted that on the Sahib Aquaponics group page).

http://sahibaquaponics.com/project-news/using-soil-in-aquaponics/

God bless

[NARDC.in]

Hi Sahib,

You are doing really good.  It looks very promising.  Too less AP people have done anything with soil in Aquaponics.  Brilliant Sahib! 

Have you noticed de-colouring of the water or a pH spike?  

If so, how did you tackle that?

I think I am not convinced and still researching before going ahead with the trial at NARDC.  

Have to take a decision in 2 days.  We are now doing the liner and plumbing. 

Please have a look at what we are doing at NARDC blog to get a feel.

Please advice us on anything that we should take care.  Any challenges you faced?  Any tips is greatly appreciated.

[TCLynx]

There are actually a few operations that do something sort of like using soil, sand, potting mix etc with aquaponics but I believe most of them are not simply filling a grow bed with them.

I think the most common method is to use a growing container.  Think plant pot, grow bag etc that has the non gravel media in it and then you set that into a grow bed that floods and drains just enough to allow the plant pot media to wick up moisture from the bottom.

Important notes are that you don't want to put TOO rich a soil mix into the pots in such a fashion that you could actually leach too much out of the pots into the water and overload your bio-filtration or hurt your fish.  Soil or sand is likely to be too compact or too wet to really work as a flood and drain grow bed media all on it's own and you may not be able to depend on consistent bio-filtration from it so I would still recommend having gravel in at least some beds or in the bottom layer of the beds with the plant pots to provide bio-filtration enough to support your fish load.

I have used plant pots with soil/compost/peat/coir/sand etc set into grow beds since the grow beds make a very effective way to water/fertilize the potted plants and the plant pots with a wicking mat in the bottom make a good way to keep the potting media from washing out of the plant pots.  If you use too much of this kind of planting you are likely to see staining of your water depending on the media you use but amber to tea colored water in aquaponics is actually normal anyway.

Morningstar fishermen call this terraponics.

Primary drawback is when you explain it, you can't call it soil free and you might be inviting more problems from soil born plant diseases.

I recommend experimenting in ways that you can easily change if you find something that doesn't work.

[NARDC.in]

Hello TCL, thanks for some great thoughts, sorry it came through a bit late though.  We constructed the wick bed and it is now operational and is working fine.  Please find attached the design we came up with.  Please suggest if any modifications you would want us to make on this. Thanks again for your tips.

[Robert J]

Interesting...  I too am experimenting with a wicking bed.  It's in my hydro system, but could certainly be fed by my aquaponics system.  My design is similar to nanniode's.  But mine does not have hte pond liner and my overflow waters the grass.  But, what is C in their drawing comes from an equalizing tank with a float valve.  imagine straight through the wall to the small tank (12" X 14") at the same level as the bed.  When the water level in the grow bed goes down, the water feeds from the equalizing tank to the grow bed, lowering the float and allowing more nutrient rich water to flow in.  as the water level rises, the flow comes up and water stops flowing.  For me, A=Expanded Shale and B= a mix of peat, perlite and worm castings.  So far it seems to work ok but jury is still out.

I've been doing a lot of experimenting with self watering solutions because I travel a lot.

[NARDC.in]

Good to see your reply, Robert.  We kept C at the bottom of the grow bed so as not to disturb the soil part.  Water flowing straight through the wall at the same level as the bed, as in your case, did you notice any water discoloration?  It should not be much because you did not use coir.

We are particularly interested in wick beds because it looks good for all tuber crops + heavy veggies and small fruit trees.  What does everyone think on these?

[Robert J]

I generally only see overflow when it rains (outdoor bed), but no noticable discoloration.

[TCLynx]

Main things I would watch out for are clogging/fouling of the gravel at your inlet, might be worth investing is some way to inspect and clean out if it starts to slime/clog up.

Also, I might want to make sure the overflow can't get fouled or have the "soil" mix wash out of it back into the AP system.

When getting into doing "recirculating" wicking bed designs, keep in mind that you are experimenting and that there are few people out there who will be able to diagnose problems you might run into if something in your "soil" mix is messing with your system chemistry.  I'm not saying not to do it, but I am saying that adding "soil" "compost" or "fertilizer" into the variables makes it Un-charted territory with few or no scientific or university studies published and only minimal backyard anecdotal experience so far being shared to go by.

That said, you might want to look at some of Vlad's posts on dual root zone fertilization (granted he was doing this more in hydroponics at the time I read about it) as it could be of interest/use in this type of growing as well.

[NARDC.in]

Thanks TCL, great tips as usual.  As of now, I could not see any problems but I foresee some problems when it would rain heavily.  I have made some easy plumbing to make quick separation of the outlet from FT quickly.  I ran the water for external plants for a week or so until all mud/discoloration is seemingly settled.

Good thing to note is that we have collaborated with a nearby Govt. Research Station to augment our own research and development activities into doing various things such as this kind of subsurface irrigation in AP, etc..  Agree it is adventurous... going to have a lot of fun doing it. 

Vlad's posts, I will surely check.  Thanks again.