Backyard Aquaponics
A place to discuss aquaponics

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what is the water flow in the pipes? What is the water temperature?

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BTW- I have been spraying PH=7.4 water on the outside of these root cubes every 2 or 3 hours (daylight only, of course!).

I would probably recommend some extra hardening off of those seedlings before suddenly sticking them out in the sun and spraying them with water (which by the way, droplets of water on the plants in bright sun can actually burn them.)

Perhaps some shade cloth to protect them from being exposed to the intense sun at the same time as being moved from the dark wet humid domes indoors.

Simply moving those leggy seedlings from their dark indoor environment out to a hot sunny location could be enough to be killing them. Not necessarily anything due to pH or water chemistry.

Also, these are the plants I started out with....but 80% of them are now dead

Lettuce, Oakleaf
Lettuce, Black Simpson
Lettuce, Rouge d'Hiver
Lettuce, Bibb
German Johnson Tomatoe
Jalapeño Pepper
Bunching Onion
Roma Tomatoe
Cilantro

+1 what TCL said.


Leggy stems and dark green leaves are often signs that a plant was grown in low light conditions. In addition, when a seedling grows in high humidity it won't develop as many stomata (which help with cooling). If you don't give it time to adjust, what you have is a plant that will absorb more light and heat than it can use or get rid of, so bad things happen.

In addition to what TCL suggested with the shade cloth after you transfer, I would consider gradually removing the humidity cover once the seedlings are up out of the ground (to help get the stomata working) and give the plants more light at the seedling stage if you can.

Scotty435-

I'm a little confused. These starts are never in the ground. I add seeds to the hole in a rockwool cube (or peat moss cube), make sure it's damp with water, add a clear cover and set on a table indoor next to a window.

I can decrease the humidity over, what, a week? And I'm trying to picture old towels jury-rigged to hang in front of these plants to provide shade. Sounds ugly! What do you guys do?

He means once the seedling has poked it's little leaves above the rock wool or whatever it is planted in not actually the ground.

As soon as there are green leaves you can remove the humidity dome or at least open it up. Provide more bright light to the seedlings and some air movement if you can to help strengthen their stems.

As for shade, I use something called shade cloth, it allows some light through but not all. It can be gotten from the hardware store or garden center.

Thanks TCLynx!

Oh, answers from 8/16 questions:

*Water now is 82 deg. F. in a fish barrel, probably a little lower from evaporation in the grow tubes.

*Flow rate? Unsure, but I have a 620 gallon/hour pump, with a 11.5 max head. The water is pumped up about 5.8 feet, so I have (5.8/11.5)x620= 313 gallons per hour available, but it's split into 4 drip irrigation tubes, so now we got 313/4=78.2 gallons per hour. To keep things balanced, I have a C-clamp on each of the 4 drip irrigation tubes to restrict flow. (long answer short> I don't know the flow for sure!)

Sorry for the confusion Jon, TCL got it right when she explained what I meant. Your temp looks ok for some things but might be a bit warm for some of the cool weather plants like lettuces. I rarely have to deal with water temps out of the 70's here so TCL will probably know better on this one.

I would actually suggest hanging a thermometer inside one of the vertical grow tubes. You might be shocked at how steamy it might actually be inside the tube. The evaporative cooling is only likely to happen where there is air moving through a wet substance, I don't expect much air movement in those tubes unless they are set up to have air rising through them quickly.

I regularly have summer day time fish tank water temps up around 82 F. The lettuces seem to grow ok in the Raft beds with aeration but the lettuces in my towers don't do as well in summer. Basil seems to do ok in the towers and NFT in summer but it definitely seems to like it hot. Tomato is more a spring/fall crop here and they seem to grow better for me in media beds. Well actually most things seem to grow best for me in media beds other than maybe the lettuce and basil.

But plants moving from a relatively dark indoor air conditioned humid environment out into a harsh hot sunny location are going to be lucky to survive.

My seed starting trays only remain indoors until I see signs that some of the seeds have started to germinate, then they move out into my nursery beds that are getting AP water and sun and the outdoor temperatures. About the only thing I protect the seed trays from is pounding rain via a greenhouse roof (no walls on the greenhouse, it is only a rain cover.) There seems to be minimal transplant shock as long as I move the seedlings before the roots are too far out of the seed trays. Lettuce I transplant at about 3 weeks at the latest. Other plants it may vary depending on the size seed starter I placed them in and where they are going and how fast the particular plant grows.

I've also found that it's better to get seedlings into the system sooner rather than later. I haven't looked into it yet but I suspect that there is some kind of conversion that takes place in a plant when transitioning from soil to AP. I discovered this purely by accident early this year when I thinned out my toms and attempted to give a few to a friend. Popped them into soil and they were completely wilted and on the floor 2 hours later. Figured they were a total loss. 2 hours after that, I pulled them from their soil pots and put them back in the AP system and 48 hours later they looked like nothing had ever happened.

TC may be onto it as at least part of the issue may be not hardening your seedlings early enough.

All the mistakes I've made! I got this system built in April (just before I lost my job!) and I have had scraggly plants inside indoor dome containers ever since, waiting for my Fish Farm to be ready for transplant. My plant starts are in small cubes, some rockwool, and some peatmoss. I have been attempting to move the rockwool cubes into the horizontal NFT system and the peatmoss into the vertical NFT system.

I have had the dome removed from my indoor peatmoss starts for 48 hours now, and I plan to put them outside under my new "hobo-shade" to toughen up before translplant:

Ya gotta do what ya gotta do.

It might help to get some more seeds started but only keep them indoors until you see them start to emerge and then move them out ASAP.