Plant growing small.

This little lady is showing classic signs of overexposure to light. You can tell by the way the edges of the leaves are curling up while the main tip is pointing down—this is a strong indicator that it’s getting a bit too much intensity, which can definitely stunt or slow growth. Your TS600 is a 100W light, and at only 30cm away at full power, it’s likely giving the plant way more light than it needs at this stage. Too much light this early can stress young plants, making them focus more on survival than growth. I’d suggest dimming the light down to about 40% and also raising it to around 60cm from the top of the plant. That should give it a much more comfortable environment, and you’ll likely see it start perking back up within a couple of days. Keep an eye on it, and if the growth takes off again, you’ll know for sure that light stress was the issue!