Things I have learnt since starting hybrid systems.

[Kobus Jooste]

The most important thing is to abandon the single pump lay-out if you want to have media beds and rafts / NFT in a compact space.  In the past, I could drain gravel beds into rafts and then to a sump full of netting.  This kept the water in the system clear and the roots in the rafts looking good.  My new lay-out is NFT above and raft at the same height as the media beds, thus the single supply line I have been using is really too dirty for NFT.  Option 1 is in line filters, and option 2 is small secondary pumps for the NFT.  I'm going for the latter.  A high head low wattage pump will be tossed into the sump as soon as I have installed a internal configuration that settles the solids out prior to it getting to the pump.

 

The second issue I am picking up is that hybrid systems tend to have "just enough" gravel rather than surplus, which means that fines and even intermediate solids seem to stay in the system's water.  I picked this up with the sump retro-fit.  I therefore think that if you are going to run a stacked design with raised beds and lots of media-less culture, you need to find ways to settle out fines the way it is done in raft-type systems, but without discarding it.  We are therefore talking in the direction of mineralization / digestion sections in our AP systems, but not yet solids removal.

[Harold Sukhbir]

Hi Kobus,

When i first planted the system on start up i developed pervasive root systems(fine long stringy roots) through the entire beds. This started clogging up the beds. As nitrates increased i replanted and noticed the roots were sightly thicker and shorter. Then i thinned the plants again and saw the roots systems even shorter/thicker. I've gathered that overplanting/low nitrates will force fine pervasive roots systems in beds.I think on startup we should plant short low demand crop and as the system matures we can plant more long term crop to allow the AP to mature and avoid fine roots and possibly speed up plant growth.  

[Kobus Jooste]

That is true, but if you have a passion fruit vine heading over the wall into the neighbor's................

[Kobus Jooste]

I need to find place in there for a swirl.

[Harold Sukhbir]

I started initially with a bitter melon plant it sucked every available nitrate and spread to cover about 3 times the space of my AP, giving away daily fruit to friends and neighbor.............and then clogged beds! This was causing the other plants to fine root as well, and even though it felt wrong to remove this plant at its prime, i had to do it. Now i have 4 large tomato plants and the raft and i feel there is more balance in the sys.

Kobus Jooste said:

That is true, but if you have a passion fruit vine heading over the wall into the neighbor's................

[Kobus Jooste]

I have the passion fruit in its own dedicated bed, but it has taken over a lot of space inside the system.  I'll be cutting it back inside soon as it is now out of the greenhouse and established against my back wall (and over it too, to the joy of the neighbour). My wife will NEVER let me remove it!!

[Harold Sukhbir]

Hi Kobus,

To me it's a no-brainer, for me the choice will always be the same, between the passion and the fruit, the fruit will obviously have to go! !!

[Sahib Punjabi]

Hahaha...too good Harold...long live passion....the fruit's not bad too :-)

Harold Sukhbir said:

Hi Kobus,

To me it's a no-brainer, for me the choice will always be the same, between the passion and the fruit, the fruit will obviously have to go! !!

[Sahib Punjabi]

Thanks Harold fro pointing out your experience with Bitter Melon. I was going to plant that but was being cautious given my experience with regular gardening. I think that I will create a separate re-circulating wicking bed for this as well as mint :-)

 

God bless,

[Harold Sukhbir]

Hi Sahib,

Be warned they grow quickly and fruit early and grow tremendously and before long your sys will have nitrate depletion. I mean they completely "rob" the sys of all nitrates. My thinking is that they will be ideal if they were in a separate AP system all unto itself. Plus, in a shot time you'll be going commercial with this one! 

Sahib Punjabi said:

Thanks Harold fro pointing out your experience with Bitter Melon. I was going to plant that but was being cautious given my experience with regular gardening. I think that I will create a separate re-circulating wicking bed for this as well as mint :-)

 

God bless,

[Kobus Jooste]

Some more lessons:

 

1) No watter what you do for inflow, they will eventually be clogged by root action if you do long-terms crops.  Perhaps the concept of leaving a bed alone foe a prolonged period of time is not a simple as it seems.  Having top inflows over the gravel develop issues.  My internal inflows are clogged after a year of operation.  Either way, water flow, solids build-up and roots seem to get complicated after about a year of operation.

 

2) Fruiting crops, especially large vines, can suck a huge amount of water out of a system.  Even for aquaponics' careful use of water, it can be too much in a drought and careful plant selection is a must if water is in short supply.

 

3) Keep going back to your old references.  You may have been searching through them to splve problem X, while there is some really nice stuff hidden in there for idea Y that you are playing with now.  I have re-discovered some wonderful ideas just lately in this way.

[Harold Sukhbir]

 Kobus said :"1) No watter what you do for inflow, they will eventually be clogged by root action if you do long-terms crops.  Perhaps the concept of leaving a bed alone foe a prolonged period of time is not a simple as it seems.  Having top inflows over the gravel develop issues.  My internal inflows are clogged after a year of operation.  Either way, water flow, solids build-up and roots seem to get complicated after about a year of operation."

Harold said : I have, in one bed, a drip grid array of pipe covering about 75% of the surface area, which I've cleaned only one time, and i now realize i probably will clean, at this rate, once or twice/yr. This spreads the inflow widely enough to limit clogging. The out pipe is a vertical 3/4" pipe, with many holes along it's one foot length, placed at one end of the bed. When i notice the flow rate from this pipe decreasing at the terminal end( FT ), I push a sharp thin metal blade through the media, along the vertical OD of the pipe, severing any roots in the process. I do this about one/mth, and this takes, all but 30 seconds to accomplish.

This is a constant drip bed, but there is no reason why the drip cannot be used in combination with an F&D bed. It is relatively simple to maintain a siphon with clogging issues.

 

Great point with the vine crop, and even if water supply is not a huge concern, it will require people with smaller systems to "micro manage" AP operations with very time consuming water top ups.(For my first system, daily top ups)

[Sahib Punjabi]

Nice to see you back Kobus...looks like came up for air :-)

 

I fortunately have not experienced this issue as yet given my gravel beds are only 7 or 8 months old. I did notice a significant root buildup in one that I had to move recently. If this is true that you need to unclog these gravel beds periodically, this kind of defeats the establishment of a nice natural echo-system. I do like Harolds idea of running "a sharp thin metal blade through the media ...severing any roots". This would leave the nutrients in the system and leave the echo-system largely undisturbed.

 

You are also correct about the continued re-visit to old references. There is so much that went over my mind initially that now makes sense as well as reminds me of what I forgot :-)

 

God bless,