Yellowing leaf tips/curling leaf tips

[Sp1232]

Hi i am currently 3 weeks into my first grow, I am growing feminised BUKU by t.h seeds. I am in veg phase, growing in a 1.2x1.2x2.0 tent with 600w mh and cool tube, 6" rhino exhaust fan and filter, I am using a 100% terra light mix and have not introduced any nutrients yet, I am using tap water which has been left for 24 hours in a bucket and I have not tested any ph levels as of yet. I am running a 24-0 lighting schedule, my temps are around 25-30 and I struggle to keep humidity above 30%. I am experiencing a yellowing of the leaves in the new growth of the very top of the plant. The plant on the left in the picture is the one that has been most affected, although it is hard to see the leaves are curling at the tips all over the plant but only the new growth at the very top of the plant has yellowing tips. I hope to tackle this problem before it gets any worse and i am a first timer so any help would be really appreciated Thanks!

 

[Sp1232]

Sorry to clarify I am using plagron fertilised substrate 100% terra light mix and it is actually the plant on the right in the picture that has the worst signs of yellowing at the top thanks also here's the pictures I forgot to attach !

 

[maimunji]

I think too much N and not enough cal mag. Give some basic nutes.

 

[Sp1232]

I haven't been using any nutes as I was told not to by the hydroponic shop owner as he explained that the soil he gave me provided the first 4-5 weeks worth of nutrients

 

[maimunji]

Can you test run off ppm? Do you have ec ppm meter?

 

[Sp1232]

I don't have a ph meter yet I am going to buy one next week, do you think that the ph level of the water that I am feeding it has something to do with the yellowing tips? I was thinking heat stress so I raised 600w mh light from 12" to 14" it is air cooled by 6" rhino fan

 

[maimunji]

No ph meter . Ec ppm meter. I think yellow tips is from some kind of micro deficiency cal, zink, iron. In my experience its from not enought calcium in the mix. I think you need to start feeding this plants only curled down leaves aka claws worried me because its sign of too much N but I think you need to ignore them and start to feed.

 

[Sp1232]

Thanks for the suggestion I will invest in a ppm meter. if the yellowing gets worse I will try starting them on feed

 

[Levitationofme]

Not every strain will be happy in a highly charged soil. But in any case. Look at your water.
Tap water can be great or horrid for growing. It may have a high PPM to start with, or be out of the useful range of PH. My Tap water comes in at 650 ppm at a PH of 9.7.
I killed a few plants before I got a suitable filtration device.

Also chemically softened water is also not optimal for growing.

 

[Levitationofme]

For a home spun solution you could try making EWC Tea and add some Liquid Kelp and a bit of extra Blackstrap Molasses after brewing. It should boost the bio activity, the kelp has tons of useful growth hormones, The molasses gets broken down by the bio activity making a bunch of useful nutrients and trace elements. and the EWC Tea will be charged. You might want to try a Foliar spray with the Tea as well.
If the time away from your plants while you are figuring out EWC Tea doesn't help them,
the Tea may.

 

[Sp1232]

Thanks levitation so I will invest in making this EWC tea and getting foliar spray and by the time I come to use them the plant might have sorted itself out(hopefully!) il keep updating

 

[Sp1232]

Turns out the soil I was using only provides 1 weeks worth of nutes, they are still alive and kicking after 3 and a half weeks thank god, started them on veg nutes today at full strength now i will just cross my fingers and see what happens

 

[DeadBaby]

I don't have a ph meter yet I am going to buy one next week, do you think that the ph level of the water that I am feeding it has something to do with the yellowing tips? I was thinking heat stress so I raised 600w mh light from 12" to 14" it is air cooled by 6" rhino fan

Make sure you filter your tap water if you are part of the city municipal water system the chlorine will kill your living soil random 2 cents

 

[Donkeybrains]

PH is very important. And try to get some Reverse Osmosis water. Tap water will give you problems. If you think it's under fed make a foliar spray and if it greens it up it needs nutes.