Backyard Aquaponics
A place to discuss aquaponics

I have set up a small system, grow bed is 6ft x 3ft x 8" deep. I have an automatic flood/drain system cycling time about 45 minutes. The fish are tilapia and seem to be healthy however all the seeds I put in the grow bed germinate fairly quickly, last for a few days and then die. What am I doing wrong?
Please can someone help? I am obviously not doing something quite right.
I am in the Philippines and seriously trying to augment a meagre pension.
Norman

What are you planting? Are the seedlings in direct sunlight? How long are you waiting until you transplant your seedlings? I usually wait until there are two to three "adult" leaves on the seedling before I transplant.

Give them a drink with watering can every 2-3 days until they get established.

Thanks for your reply. The bed is not completely in direct sunlight being in a tunnel with netting over it about 8 ft high. The sunlight coming through the netting is good and the temperature is just a couple of degrees lower than outside. My rather crude method has been just to drop the seeds onto the gravel seed bed and allow nature to take its course.
The water in the gravel bed is controlled by a bell siphon with water coming in constantly at one end, rising to siphon level and discharging into the fish tank. Once the siphon starts it takes about four minutes for the action to end and for the water level to start rising again.
The seed germinate quite quickly, grow to about two leaves high then just expire.
Is it getting too much water?
The water is from a deep well and is very good.

Sounds like damping off. I presume it is humid where you are. Seedlings hate humidity cause they are vulnerable to fungal infection. Try growing them in seed raising mix (sandy stuff) and don't over water. Keep them in a well ventilated place. Then transplant them in the bed when they have their 2nd set of leaves and they are mature enough to withstand infection.

Starting them off in compost and/or using worm juice ( diluted 1/20) is good too cause it provides seedlings with beneficial bacteria and fungi to help them wristband attack. Its similar to us eating yogurt/probiotics. Seasol guards the roots too if you have that over there. It is a seaweed concentrate.

Thanks for all the help. I am not much of a gardener and I thought one simply put the seeds in the gravel bed and let nature take its course. How wrong I was, it's worse than raising kids!!

Oh no, its way, way easier than that.

Could algae be my problem?
Most of my gravel bed is green with algae on the gravel, on examination my seedlings seem to start off well but then Algae seems to start forming around the stem of the plant. The stem appears to thin out where the algae goes around it. The plants then keel over and die. I have removed a number of them from the gravel and the roots seem to be in good condition, the plants seem to do well sprouting new leaves until the algae comes along. I am using the flood and drain system with a cycle time of about 45 minutes and a gravel bed. The water is from a deep well and has no additives. Everything is housed in a tunnel with a roof of netting, lighting is good and plenty of sun.
Can I get rid of this algae?
Suggestions please.

Algal growth could suggest high phosphate although I don't know where this would be coming from, maybe check yr well water? Other than that, too much sunlight on a nutrient rich water supply. The algae may not be killing the seedlings but maybe just having their stems coated with the wry slimy stuff is causing them to rot. Most aquarium test kids have a phosphate test.

your green gravel means your standpipe is too long thus the water level is too high
cut the standpipe down so the water level at high tide is an inch or more below the surface of the gravel

another thought is to increase airflow with a fan if you can

Thanks to both of you for your suggestions.
Unfortunately test kits are about as common here as hen's teeth.
Mr. Aristaeous comment about water level is appropriate, easier for me to increase gravel level, will be done sir.

Ok great let us know how you go.