Help please

hi this my first grow my plants are about 25 days old and all 9 of my plants are female,iam using a 400w light about 1 ft off the top of my tallest plant iam growing in biobuzz org soil,i have been using tap water after leaving it uncovered for 24 hrs and have been watering them every 2nd day,i have not given them any thing other than water as the soil said i didnt need any food/nut for upto 4 weeks.
everything was going great untill 2 days ago when the plants just wilted and lower leaves turned yellow,i have removed some of the lower yellow leaves and didnt give them any water untill today the 3rd day which i added some food/nut to i then turned the light cycle to 12/12,i have posted some photos of them in the gallery,some please help as i dont know what went wrong also will they get better from this or should i take cuttings from the top (which are still great)before they die.

I couldn't tell much from your pictures. It sounds like it could be overwatering and/or ph. Are you ph'ing your water? How are you determening when they need water? Do you have good ventilation? Temp?

iam just watering when soil is dry about 1inch below the top,i will take some better photos when the lights go back on,and post them then,and sorry to be a dim wit but i dont know what ( ph'ing your water)is.but i think you might be right about overwatering as the time before last i think i over did it.temps spot on and they have great ventilation
thanks

I would slow down on the watering. I have some plants that size and I am only watering them once a week. The soil needs to be dry when you water. You can get a moisture meeter that checks the moisture content of your soil at Wal-Mart, Home Depot, or a garden center. I got mine from Wal-Mart for about $5.00. Next you need to check the ph of your water. You can get a ph kit with ph up and ph down at a garden center, Wal-Mart(in the pet section used to check the ph in fish tanks), or a pet store. You should be able to get one for $15 to $20. I ph my water to 6.8. Ph'ing your water is very, very important. The wrong ph can make your plants sick. Hope this helped.

hi thanks i shall get that stuff today,i have just look at them today and they look a little better i think,but it might just be becouse i removed the lower yellow leaves yestaday,but all the top leaves look good ,i will take some more photos later and post them,thanks for your help..

After doing everything be careful about drainage how much perlite have you put in your soil if any. My main problem was that the water did not drain and sat on the roots so the plants got yellow.

hi perlite was allready in my soil mix,i have just tested the ph of the water and soil both are 7,and the damp meter said the soil was dry,so iam not sure what to do now shall i water them again ,i watered them yestaday?

When you checked the soil moisture, did you push the moisture meter all the way to the bottom? Also when you water you need to add enough water that it begins to drain out the holes in the bottom of the pot. And yes, if your soil is dry all the way to the bottom of the pot, then you need to water them.

My soil says it has perlite too, but not enough potting mixes (in my experience) don't drain well.

ok so when the lights went on this morning i rushed in to look at them and they are still very ill ,i did push the damp meter all the way down and it said they were dry so i have watered them untill the water started to come out the bottom,not really sure how to add more perlite without repotting them which i really dont want to do at this stage.i have uploaded 3 more photos to my gallery but again they are not clear,i will try to take more just as the light goes off at 7pm uk time ,

See the leaves in your pic? See the leaves in this pic? if you think they look the same, you are suffering from LACK of Nitrogen.

hi they dont look the same more yellow and more sort of dying,than that,does anyone know how long it takes for signs of flowering to show after the light cycle is changed to 12/12?

https://www.rollitup.org/marijuana-pics/index.php?n=3428

Looking at that PIC and the soil, You dont have alot of drainage and unless you just watered in that pic it looks like drainage could very well be rotting or at least softening your roots, cause although mine were just sprouts they looked the same on the leaf, transplanted in to same soil with more perlite and pow did she (hope) start to grow.

yes i had just watered them when i took that photo,most of the time the soil looks really dry,i will take more phtos and post them

you need nitrogen and you need it now. start at 1/2strength.

firsttimeuk said:

hi they dont look the same more yellow and more sort of dying,than that,does anyone know how long it takes for signs of flowering to show after the light cycle is changed to 12/12?

Click to expand...

You should be able to tell sex in about 2 weeks after going to 12/12.

I agree with fdd have you given them any nutes?

dont prun the yellow leaves if thay are mostly at the bottom of your plants because your plants take nutrients from older leaves.

hi i have only just started giving them nutes, it has nirtogen in it but i think i need more than they are getting,i dont need to sex them as they were female seeds when i got them,this grow was ment to be like a test for myself to see if i could do it and as far as the first 4 weeks when it was great,and the last week has been so bad ,so ireally went wrong somewhere,i think that the nutes in the soil to start with ran out,this is really getting to me as i carnt get anything to smoke for love or money..........

Remember....what we all are growing is a WEED! Hearty and stout!

Better to underwater...and let it droop a little...when you water it...it will perk up in minutes. If you over water...you drown the plant...err on the side of keeping your plants THIRSTY.