Leaf tips are black, some are turning light green and cupping downwards

3 plants, Northern Lights

One at 3 inches, 4 inches and 5 inches. Transplanted last week. Germinated (Cotton Wool) at 13th May, Planted on 14th May, Sprouted at 15th May.

It has got to be over fertilization (Foliar sprayed ONCE at full strength) Haven't been spraying ever since (4th June)

Couldn't be heat/light stress the HPS is about 1 foot 3 inches away from the plant. Schedule 16/8

Till now, I have no idea when to fertilize. Because the round baby leaves are withering away, I thought it was time to fertilize..



Sorry I had to use my hands to cover the light. HPS is high bay model with no reflectors. So yes, my plants surround the light in a circle but yet remain at a distance to prevent heat stress.

Over fert? Or is it something else?

what did u feed them that you wasn't suppose to? be honest....... anyways plain water until you get some more new growth.Also mist plants with a epsom salt solution then rinse it off after 10 mins.

well it depends what hps u have. if 150W then ofc should be no problem, but with 600W it can alr be too close.
Another question is what are the temps? 70-80 is optimal above or bellow stresses the plant, causes slower growth.
Feeding should not be necessary for first 2 weeks. then you start feeding 1/4th of recommended dosage and gradually increase from there. spraying could be the thing that caused leaf burnt.
But if you sprayed with some full strength fert, then you should spray again with pure water to wash it away. I would not be spraying at all if I were you.

Also what are your watering habits? You sure you are not under/over watering?

they still young sim so spraying is gonna be beneficial like rain and outdoor plants.Even tho i hate when it rain on my outdoor buds

well it's a personal preference I guess, I've been spraying all my previous grows and now my 4th grow I tried just to water them, well did not see any difference in grow, actually at day 14 plants were twice bigger than they were on previous grows, but that was due to other factors, like light, fan. first one 15th day, at day 5 I flipped to 12/12, second one was previous grow 20/4 throughout 14days.
here's a pic to compare:

and my room rh is 36% so it's wayy drier than it is recommended(60-80%)..

I am not saying that spraying is bad, I'm just stating that if done improperly, it can even stress the plant rather than help... also foliage feeding cannot be applied at full strength, 1/3 at best I would say otherwise it burns the leaves.. And it leaves traces of calcium or other elements so you need to spray with pure water every other foliage feeding..
well this is just my 2 cents..

Well first, without more info everyone is guessing...what soil are you in? how hot is it in your grow area? what's the humidity? What it looks like, and what it is are 2 different things...it looks like you foliar sprayed and put her in the lights, that will burn your plants. The water/feed drops act as a magnifying glass and burn the leaves...and NEVER, I mean NEVER feed a seedling until the 3rd week at least, I let my babies tell me when to feed them (bottom leaves will start turning yellow) and then only 1/4 strength nutes to start and work your way up to full strength....and I never foliar feed with anything (I grow indoors) the humidity takes care of that....AND, by the way here are some healthy 14 day old babies, that were not fed nothing but water..
This was my first attempt at growing...

I've come a long way since then..

View attachment 2693753View attachment 2693754View attachment 2693755

Yes. I over fertilized it =\ the spray burned it. It is recovering and growing, though its growing at 0.2-0.5 inch every 2 night cycles (8 hours). One of them is only 2.3 inches tall. I'm serious. No signs of burn. No signs for deficiency. Soil condition stable. No problems. Just a slow bloomer..?

Soil - Horticultural Grade Soil
Fert Foliar Spray - 21,21,21
HPS - 400. High Bay, no reflectors. Plants circle the exposed light.
Water - Every 3-4 days, depends on soil moisture
Temp - 26 degrees Celsius lights on. 23-24 degrees Celsius lights off. (Estimated, using a wall mounted air conditioning system, windows are open when the lights are on to recycle air, I live in an apartment on the 10th Story)
Humidity - ???
Water - Tap water placed near windows for 24 hours.
Light schedule - 16/8
Fans - Moving. Speed 1.

I do not plan to foliar spray when it is budding.

Ever since I posted in this thread I have been foliar spraying daily. I plan on misting them with water soon to wash off any residue on the leaves. So far no problems. I must experiment. I have gotten away with foliar spraying a plant 4 days in a row, misting for 1. Was a male plant so I decided I could learn and experiment a bit. Right now the current plants genders are unknown.

Want me to update tomorrow?


EDIT: 14 days and your plants are that big? I guess I should get some lights high in blue for my next grow. HPS isn't cutting it for veg. Did you transplant? I think I might have been too rough when transplanting.

I've always thought an indicating factor for feeding plants would be to watch out for the baby leaves, once it has turned yellow and a little bit crispy, I should feed them.


Nonetheless I have autoflowering seeds (Widow Cheese) coming in 3 days max. I assume a HPS will do wonders for them since they go straight into flowering. I can't wait to experiment growing one to maturity.

give them straight water for few days they will be ok