Backyard Aquaponics
A place to discuss aquaponics

Hey all - happy new years!

New to the board, I have been trying to diagnose the issue my plants have. pictures attached!

Some background:

Currently growing buttercrunch lettuce. Today, my nutrient levels read:
pH: 6.2 NH3: <0.2 NO2: 50<110 NO3: 0.2

Those levels have been stable for a while. December was interesting, I had an issue with high potassium blocking magnesium uptake. I didn't solve it, but I made an improvement on it. My General Hardness has been consistently high - I didn't realize this was a thing until last month! Have been slowly cycling out water, and have made improvements there as well.

While this was going on, my plants were doing fine. However, over the last 2 weeks, they have gone from decent... to near death. The roots have lost their slick feel, and have started darkening. Some have clumps the are entirely greyish brown...

Is this root rot? If so, the only solution I am aware of is sanitizing the whole system. It's a decently sized community-run AP lab, and I am hoping that there is something else to do.

Any help would be greatly appreciated!

Thank you!!

What kind of grow beds are you using, media, dwc...? I can't tell for certain what is going on but the coloration on the roots reminds me of fusarium so if your plants are wilting, fusarium might be the cause.

I think if you're losing plants I'd get rid of any that look infected, the sooner the better. Sterilizing an AP system seems impractical to me, this won't totally get rid of the organism but I would plug a UV sterilizer into the flow to reduce the number of organisms. If it's an option, I would also up the aeration a bit and possibly the pH.

Try to use cultivars that are resistant to Fusarium in the future.

Hi,

I can't tell you for sure if this is root rot or not...
But i had root rot problems and from my readings and experience i can give you a few advices (if your problem is root rot) :
- Root rot likes hot water, high nitrates levels. Try lower these.
- Remove the infected plants, but don't sanitize the whole system (unless the problem propagates and lasts for several months).
- You can try adding beneficial funghi in your system (Trichoderma, Glomus and the like). They worked well for me.
- Be sure your water is fully saturated with oxygen (add extra air pump and air stones).
- Opinions about UV Sterilizer are mixed. You can try, some say it works, but i've read some scientific studies that show they have no action on this kind of pests...

Don't hesitate to give us more info about your system (type of growbeds, media, volume, filtration, etc.)

Happy new year !

scotty435:
The lettuce is growing in a DWC, but the problem can also be seen in the nasturtiums i've got in my hydroton filled media bed. troubling!
I started pulling the plants, I'm glad you're giving me the same advice. Thank you!

SebZ:P
thank you for the tips!!
I've got 2x DWC beds and a hydroton filled media bed. total volume is ~10,000L when topped up. 2x 125gallon tanks with Tilapia. I'm using a swirl/gravity filter, and another one for the bacteria that eat ammonia. It's an educative project operated by a community organization - I've been asked to work on it, but I am an admitted amateur.Slowly picking it up though!

Reading back through SebZ comments I agree with everything he said.

High nitrates cause soft growth which is often susceptible to disease.

Because it's better if you don't have to sterilize the system your goal is more about shifting the balance in favor of good organisms. That's why I suggested the UV light and I think the suggestion of using beneficial organisms is also good for this reason. Try the beneficial organisms first without the UV light. The UV light may or may not help (some organisms are resistant, some are mobile ...) but it's worth a try.

PH 6.2 is very low, like scott suggested, work on raising it a little.

So, I went out and got a little microscope to look at my roots. On one hand, I'm glad I did... on the other hand, I'm slightly traumatized!!

Using the microscope on the roots, I found a complete infestation of little bugs - some that looked like clear aphids, some that were almost like translucent worms. they're visible to the naked eye, but without some magnification they look like little grains of dirt. all of them are moving, and have managed to spread to every plant.

As far as i understand it, actual bugs require a lot more work to get rid of. Bacteria can be fought with antibiotics, fungus can be managed with additives and UV - but a population of pests gone out of control in the water requires the whole system - including plumbing - to be cleaned. Is this a good understanding of the situation, or is there another option that I'm missing??? I really hope there is.


I;m about to do some digging to find out what these bugs are, then narrow down how they were introduced. at this point, my best guess is that they were introduced when a handful of chive plants were transferred from an outdoor garden into the hydroton media bed. I'll update accordingly!!!

Y'all are super helpful too - I'm glad I joined this board. I will try to help out other members when I'm not in the middle of damage control!!!

Cheers

if you look at the third image down (labelled 'plant 2 roots') you can make out some of the insect-specks on the right of the roots, along the thickest strand. Familiar to anyone??

Pics haven't worked buddy

-K98

Darn