Dual Root Zone (possible for AP)

[Vlad Jovanovic]

Here is an idea that I believe if done PROPERLY could be used in an AP system with fish…[edit* as of this writing, it has been used in dozens of systems with fish]. I first described what I've done in Wil’s ‘Medicinal Plants Any Luck’ discussion (there is some encouraging feedback from people I respect there, and other ideas we bounced around which might be worth checking out)…

 

The deal here was that once my AP system is up and running, I wanted be able to cater to the needs of specific plants that may have nutritional requirements that a brand new system might not be able to provide (so called ‘heavy feeders' like tomatoes, corn, cucumbers, for instance). Patience, I've been told, is not one of my strong suits. And I don't want big huge tomato plants with no tomatoes, or even no flowers, stuck in a nitrate induced perpetual vegetative twilight-zone of just green leafy growth. Yet  pouring different nutrients, or nutrient products into your AP system (like P-K, “bloom/flower” type products) may not be advisable for a number of reasons discussed at length elsewhere. So what I did was the following…

 

Research shows that plants in nature tend to specialize the function of their roots. To make a long story short, we’ll divide the rhizosphere into two categories: upper roots, and lower roots. The upper roots tend to spread throughout the top soil specializing in seeking and up-taking nutrients, while the lower roots go downward seeking out moisture, specializing in water up-take. Using this concept I’ve taken five 13cm net pots (for hot peppers, but you can go larger for tom’s etc…) and set them up in the following way...

 

Fill the bottom half of the net pot with hydroton (rinsed, presoaked). Put a thin layer (5-10mm thick) of rockwool on top of the hydroton. (I have a rockwool cube and a sharp ceramic knife, so this was easy, but you can tear of pieces with your fingers as well). The whole purpose for the rockwool is to act as a barrier between the upper and lower zone of your net pot, so make sure all the hydroton is covered.

Fill the remainder of the net-pot with a mixture 13/perlite, 1/3 vermiculite, 1/3 cocco coir. To this mixture I added about 10% worm castings a handful of hydroton, to help with compaction, and about 5% Zeolite (I might forgo the Zeolite in an AP set-up though).

Then I poured water into this top portion and noted when water started leaking down into the hydroton. This way you will know what the absorption capacity of the upper layer is. Later when feeding your plants use slightly less than this ultimate holding capacity amount. Three small weekly feedings is probably better than one large one. This is an extra pot that I took a picture of...

If you had some screen material you could line the inside wall with it, but probably not necessary.

I planted my 3 Habeneros and 2 Hungarian Wax into the net pots. They have been placed into an aerated DWC bin. The reservoir holds only water (no nutes) and the roots have begun to dangle in it. There is about a 1" air-space between where the rockwool layer is and the top of the water, so that the upper layer doen't get too moist from over-wicking. This air space might also help with oxygenation of some of the roots.

Every third day or so I feed a solution of liquid home made nutes (but you could use whatever type you wanted, orgaic hydro store bought, mineral salts etc)…I pour only enough solution as the top mixture will hold so as not to contaminate the reservoir (or an AP system) with nutrients. They are growing like mad thus far.

 In an AP setting the bottom roots would be exposed to both moisture and mostly nitrates, while the upper to whatever you wanted (though I imagine and K, Mg and P...would be among the prime candidates...and perhaps P if your system is real, real new.but P shouldn't ever really be a problem in a well fed AP system).

As long as you didn't over saturate with your solution while top feeding your plants, you should be able to keep any nutrient contaminants out of your AP system. Another benefit, would be less root mass to deal with in your grow bed (which is where this idea evolved from anyways).... I had originally planned on using 'huge' net-pot-bucket-with-drilled-out-holes filled with hydroton to help contain some of the root mass of the tomato plants, and make it easier too get it out of the grow bed when the time came. Reclaiming and re-using the hydroton would also be simple. Since I am relying on my 8 IBC media beds to pre-filter the DWC troughs, the last thing I need is a root bound anaerobic bed to deal with because of a couple of tomato plants. This method can address both the nutrient issue, and may help keep the more monstrous roots contained and more manageable. (Less maintenance to the grow bed).

[Vlad Jovanovic]

I tried one of these 7 Pod Brain Strain pods the other day and...My sweet satan..!  This is easily one of the hottest peppers I've ever tasted. It made the Nagas and Habs seem like Pez candies (wonderful flavor and aroma as well)...It was like pouring molten lava into my throat, then the burn slowly made it's way to the back of the lips. Heavy sweating ensued, followed by an almost meditative calm within Pure Red Hot Ecstasy...accompanied by that light-headedness somewhat typical of these 'super hot' varieties...only this time it was as if my consciousness had somehow extricated itself (at least somewhat) from the constraints of the physical body. This is my new favorite hot pepper!

 

[Steve R]

Are you having any issues with excess nutrient build up in the rock wool when switching from veg to flower or over time?

Vlad Jovanovic said:

I tried one of these 7 Pod Brain Strain pods the other day and...My sweet satan..!  This is easily one of the hottest peppers I've ever tasted. It made the Nagas and Habs seem like Pez candies (wonderful flavor and aroma as well)...It was like pouring molten lava into my throat, then the burn slowly made it's way to the back of the lips. Heavy sweating ensued, followed by an almost meditative calm within Pure Red Hot Ecstasy...accompanied by that light-headedness somewhat typical of these 'super hot' varieties...only this time it was as if my consciousness had somehow extricated itself (at least somewhat) from the constraints of the physical body. This is my new favorite hot pepper!

 

[Vlad Jovanovic]

Nope, I did not encounter any such problems (even when I was using the rockwool barrier between the two layers with mineral supplements). In the hot pepper pots I did not use rockwool and did not use any mineral salts.

[Steve R]

I can't wait to use this on my plants it seems like exactly the solution i was looking for!

[Vlad Jovanovic]

[Tony L]

Vlad: This is incredible.  I am going to model my AP system after what you are doing, thanks a lot for putting this up.  My browser is skipping around kind of funny so I'm not sure if I read everything but I tried to.  How are the plants doing?  What variety of cucumber is that? (You said you mentioned it but I couldn't find it).

You mentioned a solution to the nitrate problem, care to send me the link you mentioned?

[Vlad Jovanovic]

Hi Tony, glad you like this and find the thread of some use :) My plants were, and are doing great. As of about two months ago I've handed over care of the greenhouse and the AP system (located in Serbia) to some others...who are carrying on what I had started (and everything is still going well). I've moved on to some other things (most of which is still aquaponic/bioponic/microbiology related) here in the States.

That particular variety of cucumbers were called Rawa (and aren't available to folks stateside...and have been superseded even in Europe)...but the important thing there, is that they are of the "beit-alpha" type, so they are a crossbreed between the 'ol Dutch hot-house varieties, (those long seedless cukes you see wrapped in cellophane at your local grocery store, and the smaller much tastier Persian varieties. The taste and smell is incomparable to the traditional "American Slicer" cucumbers (crispy but tasteless Styrofoam type cuke)... AND they are self-pollinating (parthenocarpic) and gynocious (bearing all female flowers)...which the traditional American varieties are not. (Those last two points are the most important...all female, self pollinating).

While in California last year, I grew some parthenocarpic/gynocious of a variety called "Socrates" available now through Johnny's Seed's...they were "ok" but had some 'wonky' genetic anomalies that I didn't quite care for. (But, I suppose that's California for ya :)

Remind me please what the "nitrate problem was"..? and I'll send you the link :)

 

[Tony L]

Here is the link to the "nitrate problem" post.  I don't know if this thread was edited or not, or if it's my browser, but something seems off (slight lack of continuity).  Or I just didn't read closely enough.  Here is what you said:

"I've given some thought to the nitrate problem we spoke about. There does exist a way that is very cheap and does not require any extra space or equipment. However, if not done properly, it could get ugly. It would require that you understand what you are doing, and that you are precise as well as diligent about it on adaily basis (which I'm sure you are capable of). "

But because of the issues I'm having following the thread, I actually am not sure what the nitrate problem is either!  

Is there any reason I couldn't use landscaping fabric instead of rockwool?

I might try these http://www.amazon.com/gp/product/B0055EEOEY/ref=wms_ohs_product?ie=...

Thanks!!

[Vlad Jovanovic]

Ah...yes...now I remember. The nitrate problem refers to Shaun's problem of having way too super high Nitrates in his system and his question of possible ways to lower nitrates without adding more grow-beds (no room) or having to get rid of any fish. And no, nothing is wrong with your browser...Shaun and I had carried over this topic from personal e-mails into this thread...

So if you have really high nitrates and can't add any more plants, or can't/don't want to get rid of many fish...and are of diligent mind, capable of following precise directions and keeping it up for weeks at a time...and following through...then sure, I could send you those links etc...(I don't mean to sound all high-falutin' about it, it's just one of those process' that will have catastrophic consequences if not done properly).

You can use any material that is fish/bacteria safe in which roots can grow through...or you can forgo the mechanical barrier altogether if you wish :)

[Shaun Mavronicolas]

Tony, the "Nitrate issue" had to do with Vodka dosing and as Vlad has mentioned, DO NOT DO THIS unless you know what you are doing. If you want to learn more there is a lot of this stuff on the web, especially on forums about aquariums.

I have made a major change to my system, it is now split, so I have a RAS and a fishless aquaponic system. It has it's own growing pains but I hope to sort them out, should be possible and once it is sorted will be much better than having an aquaponic system with fish... where for me the fish production side is very important. Aquaponics where fish are part of the main loop is great if you don't expect much fish production (I am talking about a home backyard system). If you want the fish production AND the fruit/veg then you need to rethink the typical aquaponics approach.

So far, the taste of the few things we've been able to eat, cucumbers for now, are much sweeter and tastier than we've ever had from our fish based aquaponic system (2 seasons worth). We are growing using this dual root zone method, or you could look at it as a hybrid wicking bed setup. It is more work and takes more sorting out, that has been my experience so far, but if things continue to taste as good and I can work out some kinks, it's worth it. And, the fish side provides some of the fertilizer for this, and our soil garden, in a way that you can manage it. Good luck in doing so with the typical backyard AP system. Tried now for 3 years and while stuff grows, there are always a myriad of problems, and the taste of the food does not compare to soil or a hybrid system as I outlined above.

It is early days, 1st time growing this way, I will have better feedback at the end of season.

Cheers.

[Tony L]

Shaun, okay, I will read up on the vodka dosing but it's not something I'll try anytime soon.  That's very interesting, I've scoured the boards so I'm a little surprised I haven't seen mention of that.  Thanks a lot for explaining.  Your system sounds really interesting, although I'm not quite sure I follow.  You're saying you have separate systems and you use nutrients from the RAS for the AP system?  Are there other creatures in the fishless AP system?  If you have more info up about this and/or pics, please link.

After reading this thread the other day I was wondering if people take water from their AP systems to supplement hydro systems.

I got some blueberry plugs for cheap, I think I'll pot them up using the dual root method (might have to keep them in their own system due to ph requirements).       

[Shaun Mavronicolas]

"Your system sounds really interesting, although I'm not quite sure I follow.  You're saying you have separate systems and you use nutrients from the RAS for the AP system?  Are there other creatures in the fishless AP system?  If you have more info up about this and/or pics, please link."

I have not put anything online yet but will shortly.

The plant system is just that... a fishless aquaponics system. So it has a pump, filtration and most importantly a moving bed bio-filter. Yes, top up water comes from the fish side and I am busy setting up several airlift "tea brewers" that will act as mineralizing tanks - so these will breakdown the fish solids and anything else I want to throw in over about 35 days. I will allow the solids to settle out at the end and scoop out this water for my base nutrient. I will pH balance it to about 6.5 with calcium and potassium buffers over the 35 days for my fruiting plants (this is all I am growing in the plant only loop). I grow my leafy stuff in the RAS. I will have several of these going so I can add nutrients every few days to the main plant system. I will also have some non-aerated minerlaization tanks going for the option of gassing off the nitrates as nitrates in fruiting systems are not desirable in large amounts.

Hope that helps until the pictures appear in my album here.

Cheers.