Backyard Aquaponics
A place to discuss aquaponics

The appearance of a few of my lettuce seedlings (batavia variety) is causing me concern and I would love to hear if any of you have some suggestions for what I might try to fix them. The system is a small flood and drain system with expanded clay filled GBs. I flood with a timer and have loop siphons for overflow protection. During the day I flood for 15 minutes and drain for 45, while at night I flood for 15 and drain for 60. The GBs are 30 liters each and the 55-liter fish tank has just two small goldfish in it at the moment. The grow beds are in a very well-lighted bathroom, under a large skylight which is always cracked open for ventilation. (Potential burglars pleas note...if you feel like braving the loose roof tiles five stories up so you can crawl through my skylight to have at my meager belongings, PLEASE try not to knock the AP system over while you are climbing in!)

The photos attached to this post show the seedlings 19 days after being planted directly in the grow beds as seeds. The seedlings got pretty tall when I first started them as I had them in the corner of the room and they were definitely reaching for more sun. They have been moved to a very sunny spot now and a lack of light is definitely not a problem at the moment in Toulouse, France. What do you folks think might be going on here?

The water measurements from this still-cycling system are: Temp = 29 dec C, pH = 7.6, NH4 = 0.8 ppm, NO2 = 0.6 ppm, N03 = 15 ppm , Fe = 0.6 ppm, KH = 5. It might also be important to note that I have been battling high pH with phosphoric acid. Over the past four days, I have slowly lowered the pH from 8 to 7.6 and plan to keep going until it is a little closer to 7.

As soon as I post this message, I am going to move my oscillating fan into the bathroom to see if that helps out. Do any of you have any other suggestions for what might be affecting the lettuce seedlings?

Cheers,
Bill

Do you recall the date planted...
Tis my openning to say things planted with the moon phases out of sync,
Can be poor performers... I'd be tipping they were planted 3 weeks ago~??

temp being 29 C I suspect is your biggest problem. Is that temperature the water temperature? Lettuce is usually a cool weather crop if your water is getting up to 29 C then I suspect the temperature at your seedlings up in the sun could be quite a bit warmer and probably why the seedlings are drooping by afternoon.

It looks like you still have some ammonia and nitrite happening, I would recommend against dropping the pH any more at this point. Lettuce is not that picky about pH anyway. You might help things a little by adding some seasol or maxicrop to get some trace minerals and potassium since lack of potassium can sometimes cause whimpy plants. As your system completes cycling, the pH is likely to drop and you may find you have to add some buffer material to keep the pH up so that's why I don't recommend dropping the pH too far with acid at this point. Also, dropping the pH too far too fast can slow down or even kill off your bacteria as well as being hard on the plants and fish. If the pH drops too low, the bacteria will quit working.

You might just need a little more patients, sometimes it seems that the lettuce seedlings do nothing for a very long time before really taking off all of a sudden. (Sometimes it may have to do with planting by the moon, if you plant the seeds in the wrong phase, it seems they are a couple weeks behind to start with.)

Yep TC, also they will struggle.
In nature timing is everything.
Plants grows, seeds form, then drop at precisly the right time.
Along comes the rain and the seeds crack open and start their life.
If we chuck the seeds in 'our system' it is better we work with nature, than just expect.
TC, I have been watching over the last 25yrs the diff timing can make
and I can understand someones skepticism, but when you see with your own eye's
just 5 days out is enough to have low germination and moldy seeds.

Rant over

I agree C1, I've taken to planting according to the Farmers almanac as best I can (their planting dates take into account moon phase telling which times are good for above ground crops, which times are best for below ground crops and which times are best to do no planting at all.

I do have one question, what about transplanting, they don't seem to tell when that should be done. I assume transplants will do best planted during the below ground part of the cycle so the roots can recover most quickly but I'm not sure.

Thanks for all your tips. TC, you are correct that 29 deg was the water temperature. The room itself was actually around 33, so I would not be surprised if the temperatures are causing the issue with the lettuce. The basil and dill do not seem to be drooping at all. I planted the lettuce seeds on the 9th of June which was two days after the full moon…which, now that I have read about this moon stuff, seems like it may have been the worst time to plant something that grows above ground.

Toulouse is supposed to see some pretty warm temperatures for the next few days (up to 34 deg) so I added some shading to the skylight in the "glass house" and left the oscillating fan running across the GBs and the fish tank. My apartment is under the roof and well lighted, so it usually a few degrees warmer than the listed high of the day. Hopefully, the evaporation of water due to the air currents across the water will keep things relatively cool. I don’t think I will be investing in any sort of chiller for this little system, so I hope everything will be OK. Does anyone have any novel ideas for keeping this system cool if the temperatures are going to be in the mid-thirties (or higher) for a few days?

And in the meantime, I will take the TCs advice and stop messing with the pH in the system so I do not drive it down to 7 just to have the nitrification kick in and drop it down to a really low level.

Plant more heat loving plants.

What are the fish in the system? I probably won't panic about chillers or anything like that unless the water temp gets up into the mid 30's.

Then again, you could always put a bottle of water in the freezer overnight and set the bottle on the grow bed near the lettuce seedlings for the day.

Creative - I'm quite intrigued with your planting by the moon phase.

I've looked into it a bit and can't quite find an accurate guide to when and what I should plant.

I through in some seeds about three weeks back. They germinated but now are not looking 100 percent.

I'm based in Melbourne and wonder if you have any links that will guide more, or do I simply check the moon phase and plant accordingly?

Thanks Baz.