Browning leaves late in the grow

[firsttimegro]

I am 4 weeks in to the flower stage and my plants leaves are turning brown. (see image). All of the browning is on the top near the cola.

I grow in soil with PH that is between 6.8-7.0. I water as needed using a moisture probe, typically every other day but not always. The temp is 68-74 degrees day/night. I give them nutrients every 14 days. I have tried to increase ventilation, lower the temp, and flush the soil with 7 PH water for over a week now. The problem seems to be getting worse. Need help.

 

[Be Irie]

When was the last time you PH'd your soil?? Whats the PH of your water going in?

 

[Hogdady]

If you would please read this and provide the info specified, it will be easier for us to help..
How to Ask for Grow Support

 

[Hogdady]

never mind....

 

[firsttimegro]

I just checked the PH and it's 6.4. The water I have been putting in has been around 6.0, but I've changed to 7.0 in the last week.

 

[Be Irie]

Get some dolomite lime.. Powered if they have it, crush it the best you can if you get pellets.. a TBL in a gal of water and it will all be good... Once you water with the lime you should drop the PH of what you are watering with and sweep the ranges.. One time water with 6.3 the next time water with 6.7 and so on... Once you start getting down into the low 6's you will start to see the effects of lock out... You can also scratch the dolomite in but it takes longer to kick in...

 

[firsttimegro]

I have gotten the lime and mixed it 1 TBLS per gallon. Watered each plant with 2.5 cups, so as not to overwater. Do I only need to do this once for now? I will monitor the PH with more frequency. Can I use this as needed or is there anything I should watch out for with it's use?

PS: Thanks for the quick replies.

 

[Be Irie]

Next time let it sit overnight... This will work fine it will just take a bit longer to kick in... Yes, dolomite is safe to keep using and a great way to keep your PH straight. I would water with around 7 PH for a week then check the PH of the soil and adjust the watering PH accordingly. You got it early, so they should straighten themselves out in a week or two...