Backyard Aquaponics
A place to discuss aquaponics

Hi,
The system is a 230L fish tank & the grow bed is 180L & 30cm deep,it's indoor with cfls and runs on a timer with a pump that runs at 1200 LPH every 45 mins.It took 6 weeks to cycle & I added the fish 8 days ago.I have had a lot of trouble with the water being extremely hard but was able to fix it with a small RO unit.The fish food is 37% protein "similar to those used in aqua culture in Japan" (that's what the description said) & the fish are fed 3 times a day.I put around 7 lettuce seeds at the start of cycling but since adding the fish the plants are dying.I'm not sure if it's a deficiency or deficiencies or something worse.

PH 7.3

Amm 0

NO2 0

NO3 30-40ppm

The outer leaves go first,usually with yellowing spots that soon turn brown and then join up with other brown spots then finally that leaf dies.The new leaves are all in perfect condition until all of the older ones have gone.

I have added potassium bicarb to the water (in its top up) twice with no visual difference

https://imageshack.com/a/It5o/1

I'm sorry for the poor quality of the pics but it's the best that I can do.


Is this because it's a new system? is this because the fish food is bad quality? or is it that my water has a stupid amount of calcium,which has caused a lockout on something else?


Any advice will be appreciated,please.Thanks

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Looks like either a bacterial soft rot or some type of burn. I don't think it's a deficiency. If the rocks get moist or there are splashes up onto the leaves then it's probably the soft rot. If the media is getting really hot in full sun it could be a burn. I think it's more likely the soft rot - it might help to lower the water level in the bed and avoid any splashing up onto the leaves. I would also remove the outer leaves that are infected, try not to spread the infection in the process.

Hi Scotty,
I forgot to mention it's a flood & drain system with a stand pipe about 2 & a half inches deep (below the surface with a gravel guard),and all the inlets are pointing down under the media.

"some type of burn & If the media is getting really hot in full sun it could be a burn"
I think you're spot on,I had a thermometer in there and upon checking it,it said 18c,I have another spare one (exactly the same) & looked at the box & it said "liquid appliances only" ,so I got out a normal thermometer and the true reading was 39c,I couldn't believe my eyes.

So yes burns is the most probable case.I'm sorry for wasting bandwidth on such a simple problem.But I honestly thought it might have been a disease.

Thanks a lot for your help.

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It looks like there is something more sinister lurking.The new temperature (since sorting it out) is 20c & the outer leaves are still getting yellow spots - brown spots and then the leaf dies.But the edges are ok,that must have been the heat doing that.

I've been looking around to see what it might be & came across one of scottys post saying "Septoria leaf spot",I googled it & found a photo that looks just like my lettuce and the symptoms sound the same aswell; https://ag.umass.edu/vegetable/fact-she ... ria-blight

What I would like to know is how did this get into an indoor system?.All water inlets are pointing down under the media & the seeds were bought from a "certified" place & does this mean I'll never be able to grow lettuce in there again?.Thanks

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Take some more pics and post them up, I'm not convinced that this is Septoria or at least the early pics don't match it. Make them larger, it was pretty tough to see and it really helps to get both an up close view as well as a whole plant pic.

It's very easy to bring in diseases on your shoes or cloths. Many of these can float in with dust or come in through tap water as well. In really intensive growing operations you'll even see people dress in clean room garb and there will be a foot bath to disinfect footwear going in and out of the building.

Another thing to think about is bringing pests in on clothing. White flies for example, are attracted to yellow (remember those yellow sticky traps?) so if you wear a yellow shirt in your outdoor garden and then go to the indoor AP, it's very possible you'll be taking some in with you (especially if you've been gardening outside - they tend to fly when the plant they are on is disturbed).

Thanks scotty,

"I'm not convinced that this is Septoria or at least the early pics don't match it"
In one of the pics (S3700162.JPG) there's an almost leopard skin type pattern that looks like the Septoria pic in that link.
Since those pics were taking they have grown (massive) but I've been taking off the leaves as they started getting brown spots.And I have taken out a few of those plants (in hope of preventing a spread,if it is indeed a disease).At the moment there's a few (of those plants from the 1st set of pics) but again I took off all the troubled leaves,I'll leave them to develop the spots again & try to get a good photo of them.

"It's very easy to bring in diseases on your shoes or cloths. Many of these can float in with dust or come in through tap water as well"
"Another thing to think about is bringing pests in on clothing. White flies for example"
I checked for pests and I can't see anything.

I see how this could be brought in now,but I done indoor systems 15-16 years ago and never had anything like this happen.Bad luck maybe.

I'll wait for more leaves to degenerate & take some pics and post them.

If this is a bacterial problem,will it survive like it would in soil?.Thanks

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Ok I found this leaf I took off yesterday but I threw the whole plant out.This is the early stage of it(2nd & 3rd pics) & then the leaf goes like the 1st pic.The 2nd pic is the front & the 3rd is the back.As soon as the other plants/leaves end up the same way,I'll put them up.Thanks

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Still can't tell . Lots of different organisms cause leaf spots. All I can suggest is just keep the area dry and avoid overhead watering or spraying since this encourages many of these diseases. Look to see if you see any fungal spores on the leaves in the brown areas. Seeing spores is usually a good indication that it's a fungal disease although sometimes it can be secondary to some other infection.

Thanks scotty.

There's no spraying or dampness anywhere,the water level during flooding is about 2 and half inches deep & the gravel guard has a plastic cover.And no,I haven't seen any fungal anything.

I've been reading up on "abiotic disorders" & due to the heat stress from a few weeks ago,maybe the plants were under such stress their immune system got battered & something attacked & succeeded .
When I pull the infected plants out the roots look good,nice clean & white.

I'm going to remove any plant that gets it & hope for the best.


Thanks

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Hi,Just a quick update to finalise this thread.
I got some new seeds of the same variety (different supplier) & the same thing happened again.I reduced the air temperature and the plants still went bad.So I gave them a cooler water temperature (root zone obviously) & they grew well.

21c-22c root temperature was too high for this strain (little gem).I also have some tom thumb seedlings in at the moment & seem to be doing well.

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Yep, my money would be on bacterial or viral.

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