Problems with getting plants growing

[Devoid]

I am in central Texas and built a raft system based on Friendly Aquaponics instructions.

Water temperature is up to 92

ph 7.7

ammonia 0.5

nitrate 10

nitrite barely above 0

Seed starting bed

Plant Problems

Tomatoes originally looked like Iron deficiency and I added iron, then it just started getting light green all over

Pumpkins that are now completely dead

Cucumber with same type issues and it's roots

Okra - left 3 are a week or two older then the ones on right

So any thoughts or ideas on what to do to get this going? I'm looking for a good low cost d.o. meter. I'm also wondering if putting them out in full sun in just frying them.

[Keith Rowan]

do you have an aerator/airstones in your dwc? i'd suggest adding if you don't

[Daniel]

That water temp seems quite hot to me - any way you could get it a little cooler? My plants don't get full sun, but even though my greenhouse gets steaming hot sometimes, the plants do fine; I expect it is because they have constant access to water. However, my water temp is usually low 80s or less. I know I've read that lettuce likes cooler root temps, so I would expect the high water temps may be adversely effecting your plants. Just my 2 cents.

[Devoid]

I have an air pump running air stones in the fish tank and in the grow beds. I'm wondering if I need to put more in the beds. I'm liking at ordering a d.o. meter, I'll have to order more stones too.

In the net cups is a coco coir and vermiculite mix. Is it supposed to stay saturated all the way to the top of the cup?

[Devoid]

I've got 4,000 gallons of water roughly, so not sure how to cool it down enough :(

I wanted to put tubing in the ground before the tanks to circulate water through but was in a hurry to get it built.

I know the warm water can't carry as much d.o. either

[Daniel]

Wow - that's a big system! I have media beds, so nt directly comparable to your flooded beds, but my media beds are constantly flooded and my plants (lettuce, okra, tomato, cucumber, strawberries, sesame leaves, etc.) do not seem to mind the wet feet - so I would think the constant saturation of the net cups would not be a problem by itself. I have a sump tank that is buried and helps keep the water temp down, but my system is only 300+ gallons... perhaps if you gave your system some shade it would help the water temp to go down a little? Or you could try putting insulation around all the sides of the beds/tanks, so they could get a little closer to ground temps instead of air temps?

[Devoid]

Thanks for the info. I am planning to paint the fish tanks white. They have a white cover over them. I need to get shade cloth ordered to put over the beds. I need to figure out how to build an all in one shade cloth and trellis structure

[Devoid]

So I've had fire ants running about on the rafts. Is this possibly aphid damage? I'll have new pics to put up tomorrow. I noticed what looked like salt grains on some leaves. Or mites maybe? I plan to spread de over the rafts in the morning to cut down on the ants some more.

Also it seems that fire ants do something to the surface layer of coco in the seedling bed. The top layer becomes a skin like pudding. It stays a dark color like it is wet but is actually completely dry under.

[Gena]

Devoid, we also have a floating raft system. A 300 gallon tank with talapia and a 3 x 8 growbed on top. We have airators in the growbed as well. Ours is in a green house with a 50% shade cover over the top. We have put reflective insulation about half way up the greenhouse walls behind the tanks as well as Styrofoam pieces around the tanks. In the morning and evening we put frozen 32 oz. bottles of water to help cool the water down. So far we are maintaining them at 88-90 degrees with constant 100+ days. We have a fan helping to circulate air and leave the front doors open. Anything to help cool. Since your pH is so high maybe your plants aren't taking up enough nutrients? We had trouble with that also. Had to get our pH down and it's around 7.2 now but we would like to get it lower. Using hydrochloric acid for that. (just a little at a time mixed with 5 gal. of water). Going to also start adding chelated iron which is really hard for plants to absorb at your high pH. You might need the iron (Fe EDDHA)  which works better at higher pH although it is expensive and difficult to find. The Fe DTPA only works up to pH 7.5.  Hope this helps. 

[Gena]

Devoid, I forgot to add that we found a fairly good d.o. meter on ebay for 169.00. It's Milwaukee Instruments Portable Dissolved Oxygen Meter Micro Processor MW600.  Also got our shade covering on ebay as well.  Texas sun and heat are brutal....you really may just be frying them. Our plants outside in regular soil are looking like that. They just can't take the heat. 

[Devoid]

Thanks Gena. I've been trying to figure out the best way to combine a  shade structure with a trellising structure. I'm also going to need to put some greenhouse over it all, so I'm considering using the shade/trellis structure to hold up some greenhouse plastic. That way won't need to keep as extra air warm.

It turns out that a small tilapia or tilapia egg ended up in the grow bed and was eating all the roots. It explains some of the damage, though I'm positive there are still spidermites and aphids.

[Gena]

Devoid, actually that was one thing I did forget to mention, about the baby fish. Apparently they can get into your growbed. Our fish tank water goes through a pretty  good filter and we have found baby fish in them. Later I will try to post some pics of our setup. We are just East of College station and have had many days now over 100. Good luck!
Devoid said:

Thanks Gena. I've been trying to figure out the best way to combine a  shade structure with a trellising structure. I'm also going to need to put some greenhouse over it all, so I'm considering using the shade/trellis structure to hold up some greenhouse plastic. That way won't need to keep as extra air warm.

It turns out that a small tilapia or tilapia egg ended up in the grow bed and was eating all the roots. It explains some of the damage, though I'm positive there are still spidermites and aphids.

[Devoid]

Thanks Gena. I have mosquitofish and fathead minnows in the growbeds. I need to check the second bed for tilapia. I've got pretty small mesh filter but I guess one made it through and survived.

Yes it has definitely been hot. I'm about an hour west of college station, but there's no direct route