Backyard Aquaponics
A place to discuss aquaponics

Just curious if there are any published rates for Nitrate level and optimal plant growth? i know that different plants have different requirements...lettuce, greens low- tomato/peppers higher. Is there a "happy medium" rate? My growth seems pretty good, and I haven't actually checked Nitrates in a month or so. Ammonia and Nitrites are at 0, and fish and plants seem well.

I think it is more a EC ( electric conductivity) value like with hydroponics not so much the available nitrate concentration.

I got a list in my paperwork somewhere, I can have a look for you tomorrow.

There are known published nitrate requirements and corresponding "rates" .. in hydroponics...

But how would you measure.. monitor.. manipulate.. rates in an aquaponic system...

where they're always being produced and consumed...

Yes, Rupert is right. A lot of info for "optimal growth" in hydroponics, probably a lot more complex question in aquaponics. Not to mention that optimal nitrate-level might not be the optimal condition for optimal fish growth...

This video is really interesting where Murray Hallam takes a hydroponic EC-meter to his mature system. Around 3:55 in the video.

Thanks, my growth seems Ok, my Nitrates have been at zero since the system cycled. I see people like Ryan growing all kinds of fruiting plants in his newer system and then read that you should only plant leaf crops for 6-8 months. I think I'm going to just keep plugging away, add seaweed extract when they don't look up to par, and keep feeding the fish. I'm assuming as the fish get bigger I'll see more nitrates and better growth. PH finally got down below 7.6 after treating the top off water with acid. Murrey's video was interesting...far lower rates then what they would want to see in a hydroponic system, yet his growth looked good. So, EC meters are probably a waste of money for AP?

EC meters aren't necessarily a complete waste of time/money in AP....

Like anything... being able to monitor something is great... if you can interpret the readings.. and/or respond accordingly...

The point about EC readings in AP was made on the forum...long before Murray posted that video...

And it's a perfect example.... he recorded a reading of 0.2.... but his plants were/are growing fine...

So what does that tell you.... absolutely nothing...

You could take, and get... the same reading in a hydroponic system... at a particular point of time...

And your veges might still be looking fine... (they probably wouldn't stay that way for very long... )

Rupert, does that imply that that reading is too low to sustain that type of plant growth? Like you said, being able to measure anything can be a good thing...providing you know what to do with the measurement. Something I sadly am lacking at this time in my limited AP experience. Don't understand how some people get great growth in a short time, some get great growth after a longer time, and some never get what I would consider "better then dirt" growth. That's one thing I have done: compared plants from day 1 in various cultures. GB, DWC, soil, etc. So far, it's been interesting results. I have an issue with the DWC in that the water didn't stay clean enough and I had too much suspended particles that effected root growth. Since adding another filter, it's gotten significantly better. I guess if I didn't have so much growing experience, I might be impressed to "just grow" plants in an AP system, but I really am looking for that stunning growth like I've seen on a few systems. Then again, it's starting to become a bit obsessive, and I don't want to be a slave to it.lol Keeps me out of the bars I guess. Maybe I'll grow hops and brew my own organic beer...that's an idea.

Not necessarily... it just says that on that day.. in that aquaponics system... the reading was 0.2...

Seriously, it's particularly difficult to relate EC readings to aquaponics.... partly because there's all sorts of chemical salts being associated/disassociated... all the time.....

And being continually taken up the plants... at varying rates... at varying stages of growth.. through time...

... and thats before you account for dumping in 3000ppm of NaCl!

The evil one

Say what?

Old history, previous experiences, old spilt blood.

It was naughty of me but I couldn't resist.