Brown leaf tips curling in?

There are 6 different nutrients to worry about plus the trace elements (rarely a problem), so one could be high and one could be low at the same time. week 6 shows 2 other pictures. the back-left plant has a nitrogen deficiency. The progression of symptoms on the right plant is slightly different but possibly still nitrogen related. the fact it isn't presenting the same and not progressing from bottom-up as neatly means it's probably soemthing else out of balance. kinda has a hint of k-deficiency symptoms, but not quite right, either. maybe a molybendum deficiency? cold nights? again, rare for trace element to be an actual problem in regard to physical presence.. more likely pH or nute-lockout as the cause. ensure pH of what trickles out the bottom after an irrgation is not too whacky -- don't expect it to be exactly what you feed at, but shouldn't be drastically off. without knowing feeding schedule (not dosage of products that vary in concentration, i'm not putting in that much work to know all products), really can't help too much beyond that. download a 'marijuana leaf symptom chart' and you can see how the type of symptoms, where it starts and how it progresses can help eliminate possibilities, but you still need better familiarity with levesl of what you provide over time too. Fertilization is not about last night or last week.. it's evrything you've done since you started.

What's up? 😉 That looks like nutrient burn, which is pretty common late in flower. At this stage it’s nothing to stress about, either ease up on the nutrients or keep your feeding schedule, since most people like riding on the edge with a bit of overfeeding. Happy Growing 🤠