yellow leaf tips

[KingSize]

Hello everyone! Im new to cannabis growing and this is my first time posting in the forum. I have read a lot and watched many tutorials yet i have failed with all of my seeds up until now (about 10 of them) . Now im finally starting to get a hang with this last batch, surely im not even close to perfecting the art.
my problem is that 2 of my seedlings show little yellow marks on the very tips of the leaves. Ive read all the suggestions from light burn to nitrogen problems and over/underwatering, pretty much everything, yet i still can't tell what that really is. The seedling first popped out 23rd jan. so around 10-12 days old.
using water with no nutes, home ph test (soil with water) shows around 7ph.

My set up:
full spectrum, set to blue, led grow lights (3000w [80w])
light schedule 18/6
soil (light mix with perlite, no nutes)
grow tent (airing out with a fan)
humidifier (humidity never under 60% never above 80%)
temperature 20-22c (68-71.6f).

Thank you for reading!

[dphipps1020]

Your soil looks really wet to me. How often are you watering? Are you going by how heavy or light the pot is to tell when to water? The roots need air from time to time so you have to let it dry quite a bit, the pot will almost feel empty because it's so light. Usually for a pot that small I water about every 3-5 days, depending on how big the plant is.

[KingSize]

This photo was taken right after watering. i check the soil's humidity with my finger, when it is completely dry, i water, much like u, it takes me aroubd 3 days to water again.

[dphipps1020]

Yeah for that size I was thinking more 4-5. Don't go off touch, go by the weight. It's easy to over water that way if you're watering the whole pot because you can't feel the water still in the bottom. I hope that makes sense

[KingSize]

Do u believe the problem to be overwatering?

[kingfish]

When my plants are the size of yours, I spoon feed them water. I don't give them any nutes until they are at least 3-4 weeks old.

[dilvish]

when I see people posting that the PH is "around" a certain number, I shake my head. Many people make assumptions with cannabis. I was one of them.

Hell I always figured, since its a weed you should be able to throw it in a pot or directly in the garden outside, give it plenty of light and water and it will go crazy with growth. Boy, was I wrong.

You really need to get some type of accurate method to measure PH. It can make a great deal of difference with cannabis.

Sure, with just plain tap water the plant will grow, but its how it grows that is important. We want them to be large and filled with fat buds (flowers). Hence proper PH, proper nutrients, proper temp, humidity, light, growing medium etc.

In your case I'd say the soil has a little too much Nitrogen in it. What type are you using? what do you consider a "light mix". Some pre packaged soils can be loaded with Nitrogen so you need to be sure. I'd make sure the water is properly checked for PH level (6.5 for soil) and then flush it a couple of times and then let it dry out.

Specific soils like Fox Farm can have enough nutrients in them to last up to 5 weeks.

[KingSize]

The PH test that i have is using a pill with distilled water, mixed with the soil, the results show in colors, its hard to tell the exact PH, i would love to get an advice on that matter, maybe a divice or a test kit brand that u trust?
Regarding tge soil, i do not live in the US, so i cant go by soil brands, i live in europe but as soon as i get back home i will check the soil for more info. i bought it in one of our biggest store markets, speciffically made for cannabis.

im here to perfect the art, so i really appreciate your advice. Thank u.

[dilvish]

Get any old brand of PH meter as long as it fits in your budget. Read reviews before making a purchase though. Again, if the soil is too rich it may be too much for the plants depending on your water. Your temperature may be a bit low too. Try to up it to 75 or 80 and when you do water make sure the pot has a chance to dry out a bit...if the soil is completely dry when you put your finger in it up to the first knuckle then water again.

Some strains of cannabis are a little pickier than others so give it some time and it may sort itself out.

FYI 3000 Watts drawwing only 80 Watts from the socket seems a bit off...maybe read this for future reference https://www.gardenmyths.com/led-grow...h-about-watts/

[JeffInCanada]

Hi KingSize
Something is not quite right with the yellow tips showing up but I think you're doing ok. It looks like you are keeping a good eye on things. I would just keep doing what you are doing as far as watering method and not adding any nutrients. Don't have the light even close to too close. We'll keep an eye on it over the next while as see what happens. I know what you mean about finding many solutions to your problem on the internet