What's happening to our plants?

[Beth Medeiros]

We have a new system in place and are having some hiccups in our system.

 

We have an IBC tote setup: 3 growing beds, one sump bed and 1 large fish tank with only 10 tilapia in it at the moment. After cycling the system, we added the fish only to then have it be the coldest April in TX in a long time (easily 20 degrees below normal temp ranges).  We actually lost 10 fish (had started with 20) due to cold temp swings.  After rigging the fish tank with some aquarium heaters, we've been able to keep the fish tank above 60F despite temp dipping into the 40's and such.

We've had a hard time regulating our ammonia, nitrites and nitrates.  The ammonia spiked when the cold weather shut down the bacteria and while the nitrites are rising and nitrates are now off the chart, the ammonia levels aren't going down. We still haven't had more than 2 days in a row of warm weather either. Today it's back to the 60's.  We've barely fed our fish in the last week (2x) and they're small (most less than 6 inches).

Today's readings: Ammonia 8ppm, Nitrite 5ppm, Nitrate 80+ppm and pH is 7.0.  But we also have a in-tank ammonia reader that says that the ammonia is low and normal.

 

Our plants were doing well, lettuce is doing fabulously.  And then this last week we started noticing changes in our plants.  Some of our tomatoes plants started breaking at the main stem.  Leaves started changing color, yellowing. One of the watermelon plants has white spots. Basil is stunted, slow growth and looking off.

So, what are we doing wrong?  Ammonia poisoning? Or is it the cold weather?  Mineral Deficiencies?  So many things that we don't know....we thought we had a handle on this but we're finding out this is more of a challenge than we thought it would be.  We are both biologists, so we're up for the challenge!

[Harold Sukhbir]

Hi Beth,

Glad to see your progress.  Wait for zero nitrite to start feeding. The 80 ppm nitrates are ideal for growing a full range of plants, both vegetative and fruiting. Hope your temps are on the high side?

[Beth Medeiros]

Had no nitrites this morning and basically no nitrates either so the fish got fed and are super happy! Our weather temps have been in the low 80s so hopefully we are back in business! I'll check everything again later today and hopefully I'll see the nitrates go up. Thanks so much for providing assistance these last few weeks!

[Harold Sukhbir]

Hi Beth,

I'm glad your fish survived(so far) and your AP is back to normal. Throughout all this commotion your plants have been progressing and are demanding more nutrient now. Don't worry about the Nitrates, when you feed the fish you also feed the plants. I've run a system for almost 2 years with close to zero Nitrates with amazing plant growth!, because my plants were sucking up all nitrates as fast as they were being converted, due to over planting.

[Alex Veidel]

Congratulations! I still haven't been able to get the nitrates to go down in my system, lol. But my fish are looking pretty happy considering they are supposed to be dying of nitrate poisoning (this is why tilapia are good starter fish :) ) I just located a bunch of sediment hiding in my sump tank and I think that's the problem. Some of it is just hydroton dust, but who knows what else is in there. Worked on pumping some of it out today and did another water change :)