Do my seedlings look bit pale/yellowish?

[curryguy]

Hi,
what do you experts here think are the leaves bit pale/ yellowish? What could cause it?
I feel like the plants have grown bit slowly based on my last grow.

INFO:
7 days since germination
Critical+ 2.0
Undercurrent RDWC (water temp 18,5C)
Temperature 23-27 during lights on (2x300w led, dimmed to 50% @ 18") and 18C during lights off
Relative humidity 50-65%
GHE Flora (Lucas formula = grow & micro) EC 0,33 + Silicate
Water level 1" above net pot bottom

 

[Edinburgh]

Back your light off, you want those little leaves reaching for the light not drooping or shying away from it.

 

[curryguy]

Back your light off, you want those little leaves reaching for the light not drooping or shying away from it.

Do you think that is causing the pale color?

 

[Moe.Red]

Do the roots reach the water? I find that I have to top water seedlings until the roots are established enough to provide for the plant.

I use these with a pump on a timer (30 mins on, 2.5 hours off) until the plants are mature enough to find their own nutes. Hydroton does not hold much water, needs to be constantly refreshed to support life.
https://www.amazon.com/Bloom-Brothe...roponics+top+water+ring&qid=1603282744&sr=8-4

 

[curryguy]

Do the roots reach the water? I find that I have to top water seedlings until the roots are established enough to provide for the plant.

I use these with a pump on a timer (30 mins on, 2.5 hours off) until the plants are mature enough to find their own nutes. Hydroton does not hold much water, needs to be constantly refreshed to support life.

https://www.amazon.com/Bloom-Brothe...roponics+top+water+ring&qid=1603282744&sr=8-4

The roots are close the water (water 1" up to pot bottom). I have been hand watering 1-2 times a day. The hydroton & rockwool feel wet all the time.

 

[Moe.Red]

I think what is happening is most of the plant's energy is going into making roots and you just can't see the growth. According to Bruce Bugbee at Apogee these little seedlings can stand a lot more light than we give them credit for. If you look at VPD (vapor pressure deficit) which is a better measuring tool than RH% (like PAR is better than LUX for light energy in plants) your RH could be higher.

I believe if you get the RH up to the 75% range transpiration will get supercharged and the leaves will begin to use all available light to its benefit. I wouldn't change any nutes yet, just pick one thing and change it at a time.