10 day old seedling - first time grow - light stress?

Hi,

It’s my first grow and I have a gorilla cookies 10 day old seedling.

they look healthy but I’ve noticed there’s light streaks in the new leaves.
Is this due to heat stress?

potted in canna terra soil and perlite mix. No nutes.
Just plain ph water till date.

light is mars hydro tsl2000 at 50% from 30cm.

thanks

I recommend keeping a close eye on the growing environment and making sure that the temperature, humidity, light intensity, and nutrient levels are all within the appropriate range. You might also want to adjust the distance or intensity of your light to prevent further damage. Pay attention to details and she should bounce back in no time

That's a happy plant! It's common for new growth to have a light green color than the rest of the leaves.

"heat stress" - LED's do not heat the surface of a plant the way gas discharge lights do. What's the temperature in the tent?

On this page, Mars recommends a hang height of 30 cm and a dimmer setting of 25%. You're at the same hang height but at 50% so you're providing double the PPFD to the plant that the manufacturer recommends. Frankly, BFD — I'm not seeing anything other than a very happy plant.

When cannabis receives too much light, you will see "light avoidance" behavior where the leaves will "canoe" or "taco", or the impacted leaves will rotate the leaf around the axis of the petiole so as to avoid in incoming stream of (too many) photons.

If you see any sign of light avoidance, drop your dimmer setting 10% and check to see if the leaves have returned to their normal orientation. If not, drop the light level and check again until the symptoms resolve. I've been in that situation and it took about 30 minutes for the leaves to rotate back to horizontal.

When cannabis, especially seedlings, are given the "perfect" amount of light they will "pray", meaning that the petiole will elevate from horizontal to a 30° - 45° angle. You might see that if you leave the light at this setting.

I'm not seeing any signs of light avoidance. The leaves are well formed, flat, and horizontal; just hangin' out, enjoying the rays!

My strong recommendation — get a light meter. One way to find out if your plants are getting "max light" is to crank up the light until you damage the plant. That's not a good long term approach. A better way to get the most out of your light/grow is to buy either a PAR meter (not the inexpensive ones on Amazon - go with SpotOn ($300), Li-Cor, or Apogee ($600)) or a LUX meter ($35). I have an Apogee and have tested a Uni-T lux meter on a handful of lights and, unless you need the features of the Apogee, spend the $35 on a Uni-T. A light meter will let you set your light levels accurately. Oh, yeh, I've tested Photone twice. I recommend a light meter.

I've attached a screenshot of a YouTube video by Dr. Bruce Bugbee (his videos are well worth the time spent watching them). When I started growing cannabis, I used it as a "checklist" for my grow.

It looks fine..........relax and smoke a doobie.