Some of the leaves on my plant are getting these dry tips with sort of yellowish spots. What causes this?
Can you show more of the plant?
Are you sure those no parasites?
Yeah fairly sure no parasites. The rest of the plant looks pretty normal outside of a couple leaves that look like that
This may help
Charts like this are quite useless in my view. They confuse more than they help. The issue is almost always either watering or PH. If not, then it’s overfeeding (clawing/burnt leaf tips) or underfeeding (yellowing leaves on the bottom of the plant) the only exception to this is cal/mag deficiency which is easy to diagnose by mixing a foliage spray and misting both sides of the leaves. It should respond in few days given you’ve addressed potential watering/PH issues first.
It’s root burn, or malabsorption. In short, you’re overfeeding. Ignore these deficiency charts, they only really apply if you’re growing in hydro with de-ionised water as your base for your nutrient solution. Tap water + soil means you have an abundance of all of your micronutrients already. If you’re in a physical media and/or using wholly organic nutrients, you don’t have a deficiency. Nutrient companies release these charts and try to convince you you need to buy a manganese supplement, or a zinc supplement. It’s just nonsense meant to prey on people that don’t have an education in horticulture and it will only make your situation worse. I can tell by looking at the leaf in the back (see the way the colour kinda fades across it?) that it’s not binding nitrogen correctly. The pale colour shift is classic. What I would do, personally, is flush the medium (I’m assuming soil?) with plain water, use approximately 3 times the water in litres as exists in the pot. So, if you’ve got 10 litres of soil in there, pass 30L of water through it. After that, leave it for 2 days to dry out and then add feed again at 1/2 the ratio you’re using. You’re already in flower, so you need to sort out these root problems today, because the root won’t recover the stuff you burn away.
It’s a trap everyone falls into, the plant consumes more in flower so people up their feed. They consume more, but they don’t consume everything that you put in the medium. If you’ve already got a high-level nutrient solution in the soil and you add to it what happens is reverse osmosis, so the water is ripped from the root to equalise the osmotic pressure between nutrient saturated medium and the rootbed, because water moves from an area of high concentration to low concentration across a semi-permeable membrane. Flush it, give it two days, reintroduce nutrients at half the strength. I don’t know how you’re measuring the feed, but general rule is less is more. It’s been ages since I’ve done wholly organic growing, now I use salt solution nutrients in de-ionised water at 20-10-20 N-P-K, starting 550 mols/cm3 and moving to 800 mols/cm3 as you progress from veg into flowering. That is it, that is all the plant needs. If you are using organics, you need to keep your concentrations measured as well. It’s like jam, or salt preservatives you’ll overwhelm the bacteria present at the root base, so they won’t be able to break it down. That will further fuck with your pH and lead to more root damage.
Source: Bachelors in plant sciences, former master grower.
Edit: Just to add, the reason this “looks like deficiencies” is because when you saturate a plant’s root base to the point it causes burn, or malabsorbtion (see “lockout”) it can’t bind any of the essential micronutrients. Rule of thumb, if you’re in soil, not deionising your water. Every “deficiency” is caused by root problems and this is why you need plant scientists and not people who trust what AI tells them about plants.
FWIW, various LLMs seem to think this is caused by nutrient imbalance, specifically potassium deficiency. That potassium deficiency can also be a knock-on effect from overdoing it on calcium or magnesium affecting potassium uptake. Finally, another thing to consider is pH testing the soil. If you’re using a nutrient mix, you might need to flush the soil and start over (especially if you over did it). If you’re not using a nutrient mix, you should consider doing that.
