Backyard Aquaponics
A place to discuss aquaponics

Hi! I have finally a working, growing experimental system, and I have a question. First, a few quick notes about the system:

It's housed on a screened-in back porch. Lighting is artificial (one LED grow-light array right now, going to buy more soon - the one array puts out about 36,000 or so lumens and a respectable PAR for a 2'x4' area). To help the lighting situation, I have enclosed the upper grow-bed in a reflective mylar material - diamond-patterned for light dispersal - basically a grow-tent. Overall lighting is quite good, all things being equal. The system has an IBC fish tank with about 20 tilapia (the survivors), most fairly small still, and holding about 270 gallons of water. The grow area is divided between an upper grow bed filled with LECA and sporting auto-siphons for a fill-and-drain (currently cycles once every 5 minutes I think); and the lower DWC/sump, which is yet to be lit and planted. The pic of the whole system shows the setup before the lights and the "curtain".

The system is fully cycled and running well, plants are growing like crazy. The two closeups of my bullnose pepper and sweet pepper plants (the sweet pepper is the HUGE one) were taken a couple of weeks ago, and they have already doubled in size.

THE QUESTION:
My main concern right now is the density of the foliage. The plants are all starting to bloom (on schedule, actually) and the sweet pepper has a fruit. But... the foliage is incredibly and unnervingly dense. Is this a warning sign to anyone here? Should I mildly, moderately or even aggressively prune back some of the leaves, or even take off some of the flower-bearing off-shoots? Is this a sign of too much nutrients in solution?

Some notes on what has been added, other than fish food...
To help boost initial nutrient levels, I added a very low dose of a hydroponic nutrient solution recommended by a local shop. WAY below the recommended dosage. Before most of the plants were even really introduced (about 2 months ago), I had also added some basic organic fertilizers - again, low doses, and only that one time.

About three weeks ago I added what probably amounted to a rather big dose of dried kelp flakes, to boost phosphorus levels after a soil test kit revealed them to be basically at zero. I haven't retested recently, really need to. pH is holding around 7, all other fish-critical water parameters are great, nitrate levels are probably topping my kit's testing ability (around 150+ ppm), which I admit is really quite high. To be fair, I have a difficult time telling between 90ppm and 150ppm with this kit, but it is certainly high. Yet it doesn't look like this is yet to "toxic" levels for the plants, and fish are unaffected at this time.

I have a very healthy worm population, and no recent algae blooms (that's what it looked like, at least). The blooms appear to be caused by adding "worm food" to the grow beds, so not doing that again. Fish are very happy, all the plants seem happy (I have several lettuces, a couple beets, and a tomato seedling that is already exploding with growth - all not pictured).

Thoughts?

Thanks!

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Your systems looks realy neat, with a great outlook also. Any recent pics of the growth?

In answer to your question: rampid plant growth in my opinion is never much of a problem. With lower air fow from excessive crowding the bottom leaves can be subject to mold, mildew etc on tomatoes and the like, other plants thrive. So you could clear as much or as little. Plant stresses (pruning, predation, disease tempt), particularly observed in annual crops, typically result in the plant moving efforts to fruiting, seeding. So with such abundant nitrates leaves will be the proirity of the plant. Food crops don't have to always look good, the non-harvested components at least, taste and nutrition are far better measures and of greater concern. I tend to wait and see to learn, or test, by say thining on side and leaving the other unmanaged to learn. I have never been right on my first inclination as most interactions are far more complex than my primate mind can deduce.

A question for you. Why invest so much in artificial lighting, when it is in a sun room? Do you have extreme winters? I would maximize what you have gift, prior to spending money on buying. Cheers, Sam

The system looks good

At the moment,my leaves are all overlapping each other & are wet on those areas.In the day period (lights on),only the lights are on,but at night I leave a fan running so there's circulation & preventing mold.It's worked for well over a year.
Pruning a few leaves wouldn't do any harm,just enough so there's airflow through the plant.

The excessive leaf growth is probably down to the high levels of Nitrate.
If the Nitrates are at least 90ppm,the plants may have a hard time fruiting.

There is no lack of Phosphorus in aquaponics,so I would leave that alone.If you want to test it,get the aquarium one.Maybe a soil one wouldn't give an accurate reading.

I would get on top of the Nitrate though,it's a bit too high.Especially with fruiting plants.

Could say what this worm food is? & what's those squares on the grow bed?

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Thanks for the compliments and the feedback/info!! Photos attached were taken today, the first two of the bullnose pepper and sweet pepper, plus a buttercrunch lettuce (growing very fast). The third is the other side of the growbed (unlit for the moment), and then the last is of the two beet plants that sprouted (from over-5-year-old seed....), both also now growing very well. All the pics are taken without flash, btw.

Regarding the artificial lighting - the porch is completely covered, so there is no direct sun. I had hoped that the light that filtered in would be enough for something, but it was not - nothing that was planted before adding the LEDs grew or flourished (I had some beet seedlings that just gave up and died, and the sweet pepper did absolutely nothing for a couple of weeks). So, sadly, the lighting is required here. I could have built outdoors, but for a first system I wanted more control. I'm located in Central Florida, so we alternate between ultra-hot-drought and monsoon-like weather, and I didn't want the growbed to basically become a swimming pool. Plus we have some brutal insects in my neighborhood, so I'm hoping that between the screens and the green lacewing population (and the worms) that my tomatoes and green veggies might ACTUALLY survive unscathed...for once.

I am thinking of adding a NFT array immediately outside the screened porch, which would receive direct sun, run probably off a T from the pump-to-fish return line. But that won't be for several more months, and probably also not until I can breed some more fish.

The worm food is some blend of worm-friendly ingredients from Uncle Jim's Worm Farm (online seller from whom I purchased my Red Wigglers and European Nightcrawlers). No ingredient list, unfortunately, but looks to be a blend of cornmeal and flour and maybe some milled grains. The worms absolutely love it, but the few times I have added it to the growbed the water in the fish tank would turn green - not opaque, but definitely not as clear as it is now. Some algae build-up was evident at the waterline as well.

The silver squares on the GB are just extra pieces of the reflective mylar. I initially had large pieces down to help bounce the light around, figuring that any light not absorbed by the growbed would have a chance at hitting leaves. It actually seems to help, though a little less now since it's cut into little squares for sake of navigating around all the plants. I have a reflective mylar "ceiling" across the top of the curtain assembly (not pictured), so that any light that would otherwise hit the ceiling is reflected back down. The large pieces I had on the growbed threw enough light around that the "dark side" of the growbed actually received enough light to get an ornamental plant on the very far end to start growing new shoots and leaves. The worms also really like hiding under the stuff, and even in between some of the overlapping pieces (I think they get in there to procreate).

One side benefit to all the mylar has been that the recent cold-snaps - which came out of nowhere - haven't affected the plants. The heater in the fish tank is probably also helping with that (root zone temp management), and the mylar is probably helping to retain that heat (and lower my electric bill). Unfortunately I didn't have the heater for the first round of temp drops, and I lost at least 14 tilapia to most likely temperature shock. None have died since adding the heater, thank goodness. The fish tank itself is now also insulated, but I had to add MORE artificial lighting to get them back on a consistent feeding schedule. At least they don't need grow-quality lights. And thank goodness for LEDs...

Matt

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We are all wanderers.

Cool, thanks, sorry I thought they were older pics. I would had more plants to the grow bed to take up additional nitrates, and incourage the existing to fruit more. It look like you have a fair bit of room. I wouldn't worry about the leaves overlapping based on the pics.

You may be able to reflect sun in using old mirrors outside, or builders foil wrap.

Actually that is something I had put some thought and a little research into. Supposedly some place in NYC used parabolic mirrors to focus sunlight and channel it down to an underground plant, um, sanctuary - for lack of a better word. They used diffusers to spread the light back out, if I remember right, and stuff actually grew. Neat idea, would love to try it and be able to run with more natural light. Someday...

More plants are on the way. My tomato seedling has tripled in size, one of my bean plants sprouted tonight, and we're getting ready to add more lights to get the DWC and the other 50% of grow bed space operational. Time to get some more varieties of seeds!

Speaking of...has anyone had any luck with Brussels sprouts? or broccoli in anything other than a media bed? My first instinct would that the sprouts would take up a lot of room, and the broccoli would topple if not on a media bed (I read about someone doing a big greenhouse expansion and supposedly growing broccoli on rafts, but I'd like to see it before I believe it). And carrots...I'd heard they don't do well in aggregate, but a wicking-bed could solve that problem. Any thoughts on those?

Thanks!!
Matt

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green thumbs with a cash crop. Sad bit is I read "underground plant sancturay", and thought, orr that would be great for a next ap system... post-apocalypse

OK, anyone able to... Name That Deficiency??!

Brief description: Plants are undergoing some chlorosis, mottling, and occasionally necrosis at the tips or edges. I've been trying to supplement magnesium and sulfur, and potassium. Gave the system a dose of hydrated lime a few nights ago. Haven't started foliar applications yet, that's next even though it should've been first (I can't find my dumb spray bottle, so guess it's time to buy some more). No blossom-rot that I can see, and many of the plants are still fruiting. Pictured are some beets, sweet pepper plant, green-bean (which is evidently a vine and not a bush), and some lettuce.

Beet leaves: not very visible in the pictures, but they are actually slightly mottled and the older leaves are more obviously in bad shape.

Pepper: yellowed young leaves are the primary symptom with this plant.

Green Bean: some of the newer leaves are quite yellow, one in the picture shows some curious spots that suggest a deficiency to my untrained eye.

Lettuce: The youngest leaves from this plant in particular have a sort of reddish-yellowish tinge to them, which is not normal as far as I can tell. This and its sister plants were also showing the most burning/necrosis on their leaf tips (but only really the tips, not anywhere else).

Nitrates are around or below 80ppm. Potassium should be up to around 200ppm. Not sure about the calcium levels right now - total alkalinity test reported 30ppm, while calcium hardness came in somewhere between 100 and 130 (but I think that one is susceptible to nitrates, right?).

pH stays between 6.8 and 7. Airflow is hopefully good, since I cut many large vent flaps in the light curtain.

ANY thoughts are welcome!! FWIW the fish are doing extremely well. They're about 6" long and are on the recommended feeding schedule.

THANKS!!

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We are all wanderers.

Yellowing of the young leaves is probably caused by an iron deficiency. Are you supplementing with iron and if so what type?

I would stop supplementing with sulfur and magnesium but continue with the potassium if you start seeing symptoms of a deficiency in this. I don't think either of the first two are needed and may be messing up your nutrient balance. Having said this we do see the occasional magnesium deficiency. Potassium usually causes yellowing and necrosis along the leaf margins on older leaves.

At this point I'd supplement with a type of iron that is available to plants at your systems water pH.

It looks like heat stress.
The bean leaf 20200124_185344 definitely is.I had that last summer on my french beans,when they grew out of control.

It also looks like an Iron deficiency too.

What's the air temp in the grow bed? & how far away are the lights from the canopy?

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Thanks for the replies!!

OK, so yes, iron supplementation... this has been on my mind the last day or two because my tomatoes won't fruit even though they flower. I supplement approximately every three weeks with 11% DTPA iron chelate. Last application was 3 grams on 1/22. This rate was based on the application rate of 2mg/L in 1395 L of system water (which is actually 2.79 grams, but I over-measured and was in a rush). Sounds like I could use more, and/or an iron checker (I have no iron testing equipment or chems right now).

Grow lights are LED, and are located 24" above the grow bed surface. The bean plant rises at most 12-14", and the temperatures over the last few weeks have actually been in the 60's-70's. The lights themselves put out very little heat. Water temperature is kept at 84 degrees (except a few nights ago the ambient temperature dropped to about 37 degrees quite suddenly, and the system water read 78 - luckily the fish were not bothered).

Interestingly that bean plant leaf is the only one to really exhibit those specific symptoms, the rest are a graduation from green to yellowish.

How does an iron concentration of 2-3 ppm sound? I'm fairly sure I don't have that, but I can calculate and dose to reach that point fairly quickly.

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Adding those 3 to the water could be causing a problem.Adding those 3 could be causing a lockout of at least one of them.Try foliar spraying Potassium.

Are they dual spectrum? (maybe a reason for the tomatoes not fruiting up as well).

After looking at the pictures again,I don't think it's an Iron deficiency.I can't tell from the pictures but can you see green veins on the top leaves (newest leaves) that have started yellowing?

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I haven't looked back through your thread but this sounds like an enclosed growing space. The tip necrosis in the lettuce could be due to high humidity and lack of air movement. Problems with these could reduce the plants ability to channel calcium to the leaf tips (there is probably enough calcium in your system, it just isn't getting to where it's needed). Rapid growth which you've described can be a contributing factor.

The high water temp is also not ideal for lettuce but I'm not certain how that would affect it. If the air temp were higher I'd expect bolting.

I still think that there is an iron deficiency. If the DTPA iron allows and you're OK with the discoloration it may cause, try spray applying it to the plants. You could also just test it out on one or two to see if this is the solution (probably the peppers are the best bet for this).

The higher the water temp the lower the oxygen levels. 84 is a pretty high water temperature for vegetables. I'm just wondering if the lower oxygen levels might affect nutrient uptake in this case. Hydroponic growers usually shoot for lower water temps than you have. Oxygen is needed for some of the chemical reactions involved in nutrient uptake. With the rapid growth rate it might contribute to lack of calcium at the leaf tips and maybe the iron as well.

The LEDs are full spectrum, and according to the manufacturer's specs are designed to mimic the sun's spectrum fairly closely. It is an enclosed space, and the plant density is surely not helping that. Air-flow concerns and calcium uptake concerns were what caused me to cut vent flaps. Airflow may still be a problem.

The lettuce seems to handle the water temp alright; it grows vigorously and hasn't bolted this whole time, not to mention it doesn't taste bitter (well, no more so than store-bought lettuce, though my wife seems to like our lettuce home-grown significantly better). The only plant that tried bolting so far was a cilantro, and clipping the stalk took care of that.

I have three air stones in the system right now: one in the fish tank, and two in the DWC/sump. All driven off a fairly powerful air pump. I certainly won't rule out O2, though my O2 tests have never indicated a problem...that said, my comparison vial set is technically expired (even though the tests themselves are not), but typically the level stays around 8ppm. I need to buy a new comparison set and make sure...

As for the veins, it's difficult to tell to be honest, and seems to vary by the plant. Here's what I observed:

Bean plant: the yellowest leaves have the greenest veins. The newest leaves seem to be yellow. Only a few of the older leaves appear to be susceptible to the intra-veinal yellow spots, but tend to still be green throughout. Other older leaves look relatively normal.

Beet plant: the veins on one beet plant have turned rather light (or maybe they were always that way), the new leaves are a solid green but the old leaves are mottled, with lighting intra-veinal areas or yellow spots in the more severe places.

Sweet pepper: newest leaves most affected, veins seem more yellow than the rest but the leaves in general are mottled as well. (pictures of top and bottom of a representative leaf attached). One thing to also note is the newer leaves are presently curling upward from the sides.

Cilantro: Only major symptom is necrosis on the leaf margins, and only seems to be affecting a few leaves (not throughout the plant). I didn't report on this one before because I frankly forgot about it, but it seems to show symptoms faster and more readily than the other plants. It was really the first to show signs of edge necrosis and some speckling. The leaves in general are a solid green. (picture attached)

The tomato plants are generally green and growth is vigorous. There is only a little intraveinal chlorosis on a few of the leaves, but most appear properly formed and there isn't much in the way of leaf-curling that I can tell.

Hi-res photos here: https://photos.app.goo.gl/gkMDKLnxtuqAw5EK6

Thanks!

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We are all wanderers.

I'm almost 100% certain it's heat related.The air temp inside the grow bed will be different than the leaf surface temp plus R-humidity & the more plants that are there,there hotter it will get.

The weird mottling on the beet leaf is also heat,I get that when I don't move the lights up.

There might be a deficiency but I can't see any obvious signs.Sometimes pest & environmental problems (stress) can look like deficiencies.

I'm sorry,I can't help anymore.Hope this helps

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