Yellow tips on my big leaves?!

so basically i have a set up with 400w high pressure sodium light. my humidity is usually between 39 and 50% temp between 69F and 84F the ph of my water is 7 and the soil has nutrients in it to sustain the plant for the first few weeks which i am currently in. the plant are at the stage of the their fourth set of leaves forming ant they are about 12in tall with the light a further 15in from them. the big leaves are turning yellow and curled up as they look to be drying out at the ends. ANY IDEAS ANYONE????????????

well the p.h of ur water is too high for starters! i usually have my water around 6.3 but didnt know this untill i was in late VEG - ur soil might be preventing ur ladies getting the nutrients it wants so id try flush or get a PH kit and test ur water if i was u - wot strain are u growing tell me me bout ur grow and ill try help u

cheers. well my ph kit isnt very accurate as it the one where you put a few drops of solution into the water and see what colur it turns. so i think mine is just under 7 but not sure. my strain is green spirit. s there any way to test the ph of the soil as i have one plant in different soil which is doing the best. also when flushing the soil do i need to remove the plants from the soil. and afterwards does that mean that there will no longer be any nuts in the soil so i should my own solution????????

ok well to begin with when you flush DO NOT REMOVE PLANTS FROM SOIL - that is a no no! all you need to do is find some water (i dont use any tap water any more) as it was unreal! the PH was like 7.8 so i buy bottled water now at 6.4PH and add a few ph down drop its to to get it around the 6.1 mark. so when flushing make sure the water u use is at a good ph and then leave the plant in the soil and use 3 X time container! so if ur growing in say 5 gallon pots u would then flush with 15 gallons of water. U get me? always use 3 x the amount of water to the pot size - this then clears all the soil of salt build ups!

second of all the way you test the p.h of your soil is as follows:

either buy a soil tester kit which i have done ive also bought a digital p.h. pen which only cost $25 this will give u a precise and accurate p/h reading which can only be beneficial to ur ladies - so the way to test the ph of the soil is when u water ur plants - and water comes out the bottom of ur pots? u with me - well take a sample of the water that comes out the bottom of ur plants containers and then p.h. that water - this is called the RUNOFF and is a very effective way of checkin ur soils ph - if you put ur water in at say 6.2 ph and then it comes out at a p.h of 7 u know u have some build up of salts!

im still on my first grow myself but i have came across so many problems in this first grow i kinda picked alot up - if u need any help of want to know anything feel free to ask me about anything - and if i know ill be more than willing to help u correct any problems.

good luck with ur grow and hit me up if u need any advice

...and yes after u flush ur soil there will be nothing left in ur soil all the salt build up ect will be flushed - this might be an option for me - im going to do it in the bath tab i think as its guna be alot of water for my 3 ladies

nice1 one mate. theres one other thing which it might be as one of my ladies is in different soil which is the biobizz soil and she seems to be doing better than the others. do you think theres any chance that the other soil has run out of nutes as i am supposd to start giving the biobizz lady nutes soon. but im gonna ph my run off water before i do that. but just to confirm. i want my run off water to be about 6.5 yea???

yeh i would maybe say so - the bio bizz is very good soil - i actually use the bio bizz light mix for seedlings and bio bizz all mix for normal - yeh water run off around that mark

any other things ur not sure on just ask - im into week 4 of my flowering now! crystals and real hard dense buds forming - i cant wait to SMOKE a blunt!