First time grow

Hey Growmie, Looks like some mild nutrient burn or possibly a bit of potassium deficiency. I’d check your feed strength and runoff—maybe dial it back a little. Also worth checking your light distance since crispy edges near buds can be from light stress too. Still looks like a healthy plant overall, though!

looks like a potassium deficiency. at this stage give your plants some cal mag and pk. At 4 weeks is when your plants will start needing increased amount of k and cal mag and they stop stretching and need less nitrogen

Its at the bottom of the plant, those leaves dont even get enough light and its perfectly normal for the lower leaves to start dying and yours dont even look that bad. Keep going and keep an eye on the top leaves, those are the ones that really matter ;) happy grow mate!

Left hook, right cross, bobbin and weaving. Your tips also look to have osmotic damage from high ec, means salt content in the medium is getting up to its limit. High EC (Electrical Conductivity) in hydroponics or nutrient solutions can cause lower leaves to brown, a condition often referred to as "salt burn" or nutrient toxicity. Leech your medium to lower salt content. Add water to dilute the solution and balance out excess salts, once leached reapply ph water with balanced fertilizer. Everything should bounce back. Water will flow in direction of highest salt concentration. When your medium becomes higher salt content than the water in the plant then all the water in plant wants to suck itself back out this is displayed as burnt tips. Gluck. I do see some deficiency creeping in up top too, just looks like a little magnesium, but it's hard to tell, once ec gets messed up then every process that deals with water within the plant is effected, first sort your ec and make sure to check ph too, if everything lines up then look at rectifying possible deficiency if it still presents.

PK defeciency