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I am trying to grow a sunflower using DWC hydroponics (first time trying to do anything with hydroponics). I placed the seedling in a mixture of 1tsp each of 3-part General Hydroponics nutrients mixed into about 4.5 gallons of water with an air stone underneath the netting pot, wrapped the container with a black plastic bag to keep out light and placed under an LED light at about 50% brightness (it uses about 250W, nothing too serious).

After a few days the second layer of leaves began to grow but do not look very healthy. They are curling downward, wrinkled and a bit stiff. The first two leaves lost a bit of their shape and became "wavy." See attached for photographs.

Any ideas where I should start troubleshooting?

The PH is at 6.0 I have an EC meter and Cal/Mag solution on the way. The water came out of a Culligan jug. The plant is on day #5 in the water. If it is still growing at the end of next week I was thinking about either adding Cal/Mag depending on EC meter readings or switching from Culligan to tap water with the same nutrient mix. Another thought was to decrease the nutrients by 50% to see if the plant performs better and if not then adding nutrients to make up for the 50% decrease and step up about 10% more at a time.

Thanks for any advice. Just starting what I hope will be a very educational journey.

I don’t do hydroponics, so I can’t speak to that part of the possible issues, but I have 2 or 3 observations

- seedleaves (first leaves) becoming wavy is pretty normal for sunflower seedling.
- Sunflower needs deep root depth — if the root growth is blocked in any way (I question whether hydrotron could obstruct the relatively thick and brittle sunflower taproot) the first set of leaves might display this kind of leaf malformation .... I CAN speak to seeing something similar when sunflower seeds are grown in too tiny starter pots without timely uppotting.....
- If those true leaves are displaying stippling, it could also be some kind of sucking pests Like mites?