Sub Irrigated Planter (SIP) with Living Soil, following the horizonal method?

[green_machine]

Hey folks,

 

I got a new 2'x4' grow space and want to set up a living bed in this.

 

I have wanted to grow this way for a very long time but space restrictions have always stopped me, with my new larger space I am finally going to take the plunge and try it.

 

I want to build a SIP to manage the water within the system and have been doing a lot of research on the best way to achieve this and this is the current plan.

 

 

I have found a 200-litre half-pallet plastic tote (200l hogbox) which will fit in my tent, it is waterproof and is raised on legs. the bottom layer would be the reservoir, which I would fill with lava rock. I prefer the idea of lava rock over using the 4" waste pipes used by a lot of sips as I think the lava rock would be more beneficial for bacteria (I am thinking of a fishtank bio-filter here). The aim would be to have around 4" of rock at the bottom and to drill the overflow at around 3" to give me separation between the water and the sand filter while also adding air into the bed. I am also considering drilling a separate drain and tap into the bottom of the bed to help flush the reservoir out as needed.

 

Above the lava rock, I would do a layer of fine gravel, I was thinking about using lechuza pon (although this would be expensive) or maybe horticultural grit, or maybe sourcing some smaller pumice and zeolite. The main purpose of this layer would be to support the sand filter above it and to stop it from entering the reservoir.

 

The sand filter would be there to stop the organics from getting into the water table below. this would be a thin layer at only 2" in-depth

 

The clay layer and the wood chips were idea's taken from hugel culture beds, from my research any long-term organic bed would require a carbon source in addition to the organic being top dressed and the green manure. The clay layer would be the smallest layer at only roughly 1" in depth, I would mound the wood chips directly on this in the middle and then fill the rest of the tote up with my living soil.

 

I am generally following the work of Leighton Morrison with this build but I have adapted it and used some of my own ideas as well. While I am excited to try this I would sincerely appreciate it if some of the more experienced growers could take a look at this set-up and give me their thoughts.

 

I don't want to invest a lot of money and time into something and find I have made basic mistakes so in that vein of thought @MindSoup @lildaveham @FarmerPalmersNT @BilgePump What are your thoughts on this does this seem viable are there any improvements I could make on this?

 

 

 

[BilgePump]

Great idea this.

 

The only thing i can see being an issue is the lack of a physical divider or membrane between the lava rocks and the grit and subsequent layers.

I feel like you'll want something keeping the voids in the rocks free of smaller particles which will inevitably end up settling there given half a chance.

A bit of weed suppression membrane/landscape fabric or if you want to be fancy some terram would all do the job adequately I reckon.

 

Putting in a drain is also a good idea, water butt taps are a few quid and might fit underneath?

 

Good luck with the build dude , im keen to see what you come up with

 

[MindSoup]

Don't know enough to really offer any guidance, I did consider a SIP for a while recently, the only reason I decided against it is my lack of headroom, I think they're a brilliant idea. 

 

I guess you've seen the earthboxes they have over the pond? What's about the autpot tray 2 grow? Not saying you should necessarily go and buy one but good designs to draw inspiration from. An Aquavalve in the reservoir of a SIP could be the ultimate low maintenance system, although you would need some way to remove it for cleaning every now and then. 

 

Look forward to seeing it come to fruition 

Edited May 19 by MindSoup

[Shumroom]

Love the idea of making life simpler 

 

Good luck with the system build,

I'll be watching closely.

 

It would be something like this that might make living soil an option for myself

 

Atb

 

 

 

[Military Grade]

3 hours ago, green_machine said:

 

Nice draw up mate

i'm guessing this would help prevent things like gnats?

 

I'm still trying to find a auto watering system that fits my situation.

[ipju]

Looks real nice but I don't understand how the water reaches the soil? Can the lava rocks and the sand wick the water up?

[MindSoup]

@ipju yeah you need a bit of the soil to be submerged, just a small section, getting the right proportion is the key to success from what I gather. 

[green_machine]

@BilgePump Thanks for the advice mate, I was a little worried about not using a membrane to separate the sand from the reservoir so it is good to see this confirmed. I had to do some research on that Terram fabric, but that is just what I need, so I will try and get some with the aim of using this just above the Lava rock and below the gravel layer.

 

Do you have any thoughts on what gravel to use mate, the lechuza pon is very tempting but it is pricy and I worry maybe I am just buying into their marketing, I could also use horticultural grit, it is far cheaper but I worry it may not wick as well and keep that perfect water/air content the way the pon does. I wonder if I could get away with mixing both pon and horticultural grit for this layer.

 

 

@mindsoup I have looked at the aquapot tray2grow system and it is/was a strong contender. The one issue was I felt it was a bit small it fits a 1'x3' bed and I really wanted to maximise the size of the grow bed. The set-up above is a 60cm x 100cm bed and is larger than what I could get with the tray2grow. However, that additional volume is mostly being eaten up by the internal reservoir so I am still tossing between the two systems in my mind.

 

 

@Military Grade thanks mate, Paint pro over here Picasso eat your heart out .

 

On a more serious note, Fungas gnats are a bit of a worry mate, I think provided your bed is healthy and contains a good selection of fauna you will just out-compete them, but I have seen a few beds go south from over watering, so having a water reservoir underneath with stagnant could be an issue. I have been considering running an airline down into the reservoir and connecting it up to an air pump, this might have the benefit of maintaining the biofilter in the lava rock. I think I remember reading something from @Amarillo slim about this. I think he was growing his clones or seeds out on a tray filled with horticultural grit with water at the bottom and an airline running below the grit.

 

@ipju So my understanding of water movement through capillary action (wicking) is that it is dependent on particle size rather than material. There was a farmer in Australia who did his PhD on growing in SIPs and tested the capillary action of lava rock, compost and sand. All 3 were able to move water, the lava rock was the least efficient and the sand was the most efficient with compost between. If I were going to go with a more traditional SIP with a 4" sewer pipe as my reservoir, I would probably rely on compost to act as my wick with a membrane to separate this from the reservoir. However, I am trying to create different regions within my grow bed and lava rock is a great material to serve as a home for various aquatic bacteria, including serval soil species that are able to convert to living underwater. I hope that by having a healthy population of bacteria in my water reservoir I can keep the water from turning stagnant and anaerobic. Also if there is any run-off from the main bed into the reservoir I hope the bacteria can convert it into usable nutrients for the plants.

 

 

[NormanNugget]

Hey @green_machine love the idea of this and will be following keenly. 
 

I’ve been looking at the Autopot ‘Easy2Go’ kit to keep some plants watered whilst I’m away. It’s essentially just an aquavalve you stick in your own tray. Could that work for you as you get more flexibility in terms of size? You could get a 100 x 55 x 15cm garland tray and find a planter to sit in that.

 
I checked the specs on the Easy2Go, it says it can handle a tray up to 2m2.

[NormanNugget]

I’ve also seen Autopot have a product called Aquabox Spyder or Straight. These have a central autofilling reservoir with capillary matting which wicks water into the surrounding soil. 
 

Certainly no longer sub-irrigated, but auto-irrigated none the less!

 

 

[Greenfingers420uk]

Following this thread Sounds great, good luck 

[BilgePump]

@green_machine just use horticultural grit mate ,pons just gimmicky crap.

Id be inclined to try and get a bit of bamboo charcoal in there though, and me being me I'd probably use akadama over river clay

 

[Amarillo slim]

9 hours ago, green_machine said:

m @Amarillo slim about this. I think he was growing his clones or seeds out on a tray filled with horticultural grit with water at the bottom

 

This?  Aqua-value in a tray, no airline.   

 

 

Hort grit only really needed for smaller pots like that.  

Edited May 20 by Amarillo slim

[NormanNugget]

Sorry to hijack the thread @green_machine… 

 

@Amarillo slim do you use your gravel tray with standard pots? I want to do this for keeping mothers and wonder what pots will be best. Currently on 0.7l square plastic pots.

 

 

[green_machine]

Thanks for all the suggestions folks, I hadn't seen the aquavalve mentioned by Norman and used by Slim and that is a bit of a game changer for me.

 

I'm currently working on an updated design, based on the system Slim uses and will update with the new plans later today for everyone to have a gander at.

 

I really like the new design it has some distinct advantages over the SIP system mentioned above and I can't wait to share it.

 

I'm so grateful to have access to the collective growing mind here at uk420, I can always rely on you guys to take my ideas and make them special.