Do I have Nutrient burn and how to fix it

[Manhattan]

I planted an auto flower on 12/31/20 in Fox Farm Ocean Forest potting soil in a 3 gallon plant warrior pot. Then two more around 1/26/21. They all started out great. The seedlings grew quickly. But after a few weeks the leaves started to turn brown on the edges. I thought it was nutrient burn and read to just let it run its course and it would go away. I have not added any nutrients since I understood that I did not need to with the Fox Farm Ocean mix. After a few more weeks, it just got worse. Entire leaves turned light brown and curled under. I have been watering with NYC filtered tap water. Using a Brita filter. The PH of the filtered tap water is about 5.79 but the run off water was about 4.4ph. I just received ph soil test strips which indicate soil ph of 3.5. The growth also looks stunted measuring about 5 inches at 6.5 weeks. I think the ph is not letting the plant absorb the nutrients in the soil. It is also in a grow tent with LED light on for 18 hours, off for 6 hours with a timer.

What is the best course of action? Should I try replanting in new soil? The ph of the Fox Farm Ocean potting soil is supposed to be 6.5.

This is my first attempt to grow. Thanks for any advice.

[Tedtheclown]

Get your ph up quick! Search on the gwe website, good info on there!

[Rwise]

With them being autos, they are almost done, finished, kaput. At this point there is not much point to keep going other than to fix the issue for future grows. This is why I dont recommend autos for new growers, when (not if) you have an issue, there is 0 time to fix it! Use that soil to grow blueberries as they need acidic soil MJ needs neutral soil. Your PH at this point should be about 6.7, not 3.3.
I dont use FFOF but I have read its a bit hot.

[CaptainWiese91]

I think Rwise mentioned everything you need to do better.
First of all autos aren’t good beginner strains. And the PH is way off.

On the main site there is lot of articles on how to grow autos and how to maintain a proper Ph during the entire grow.
Because it seems like you didn’t do the research good enough about growing cannabis. Sorry to Say.

Start over with some new seeds and research a lot more info about growing “.

[RetiredGuy]

If you weren’t adjusting the PH of the water you used to water the plants and it was at 5.8 this definitely needs to be corrected next grow. I am growing autos for the first time. I read that 100% ocean forest was too hot for autos. I used 100% happy frog with 20% extra perlite on the top half of my 5 gal pots. I used 50/50 ocean forest/happy frog with added perlite on the bottom half.

I use a digital pH pen to adjust watering pH and to monitor runoff pH. Like the guys above mentioned, I learned these things were required on the main site before starting my grow.

I germinated seeds the last week of December and my plants are still happy.