I do like what WW said. Get education and research more for the proplem you are facing.
especially as nutes are concern because u can easily burn your plant.
my opinion is:
AS long as you have a proplem with only lower leaves and the most of the plant like 90% are green and healthy I suggest that u go on without messing up with nutes. " I can see some of the top leaves are fading on the green color so I think u need to add some nutes".
Usually yellowing lower leaves means that you are lacking of nutes which mean the the 3 main elements N-P-K plus MG not only nitrogen. so I think you need to repot with fresh soil because your soil is losing its
There is something u need to pay attention to which is that u r washing off nutes of the soil as u water the plants , in general the nutes in the soil will last between 2 up to 4 weeks.
So you need to repot with fresh same soil and see if the plant recovered and got greener better than adding nutes that might get you in trouble if you didnt get the right amount and mix.
Tip:
usually soil manufacturer set their soil to 5.5ph-6.0ph assuming that your water will be 7.0ph so when you add the water it will balance to the ideal range 6.2-6.8.
here a pic for a figure that mightg help you diagnose symptoms.
platii Reviewed by platii on . started a new grow what would be a good way to get nitrogen in the soil ??? i need to know if bone meal would be good for a indoor grow,,to keep my nitrogen levels up and what should i use to boost the flowering stage.. Rating: 5