Any idea why she is growing slowly? Little leaf already yellow... too much light? To close? It was 40cm. Now its 60cm. Humidity? Hard to keep more than 50%
Hi mate, I'd make sure the soil is kept moist and your PH is between 6-6.5. Soil looks quite compacted so your roots will be struggling to push through. Maybe start feeding her a little nutrients. Doesn't look like light burn, more nutrient deficiency.
Good luck with your grow I hope you get the best taste of buds and healthy plants! Take care and stay lit! I will drop by sometimes to check on your process! Say hello if you ever visit my page!
Greetings from L.S.T 🙏🏼🌟