Yellow Fan Leaves Curling and Dying. Brown spots PLEASE HELP!

What type of medium; soil or hydro? SOIL
What brand and type of soil? GARDNERS GOLD ORGANIC POTTING SOIL
Indoors or outdoors? INDOORS
What strain?
How old are the plants? 55DAYS VEG (STARTED FROM SEED)
What type of lights and how many watts? 600WATT mh
How far from the lights? 22INCHES
What is your watering frequency and source of water? SOURCE OF WATER IS TAP WATER. TAP WATTER
IS LEFT OPEN FOR APPROX 3-4DAYS. i WATER EVERY 3-4 DAYS
What, how much and when was it fed? NPK? JACKS CLASSIC 20-20-20 i WAS FEEDING EVERY TIME LOWEST DOSE. 1/4 OF SCOOPER
What is the medium/runoff pH and PPM if in hydro? SOIL pH IS 7.5-7.8
What are the temps and humidity in the room? 76-78 DURING THE DAY 68 AT NIGHT
What size pots? 5 GALLON BUCKETS (2 PLANTS PER BUCKET)
Any bugs? Look real close. NO
Any other pertinent info?

Grow Tent w mylar lining 4x4x72in
600watt Metal Halide with cool hood reflector
Carbon Filter with exhaust fan.
I have a Fan on the outside blowing fresh air into the bottom of the tent. Then as seen in the picture i Have the exhaust
fan sucking out and exhausted outside. I am using Organic soil. As seen in the picture I have 2 plants per 5 gallon bucket (i know stupid).
I let my tap water sit for approx 3 days then water. I was feeding them nutrients every feeding, 1/4 of this little scooper. I am
using Jacks Classic as I am only about 1 Month and 20 Days into Veg. I did start from seed. I have a rapitest soil tester and the reading is around 7.5
Up until about 2 weeks ago, everything was on track. Now Leaves are yellowing and starting to die. Brown hole like patterns on some of the leaves.
Seems like that they haven't really grown lately.Temps are around 78 degrees. Light cycle is 24 hrs/day. Please any feedback would help! Pics below!
http://yfrog.com/7hphoto2vqj
http://yfrog.com/bhphoto4kyj
http://yfrog.com/emphoto3ycj
http://yfrog.com/03photogpyj
http://yfrog.com/jlphoto5hkj

Ph 7.5-7.8 is way too high.

Mother's Finest said:

Ph 7.5-7.8 is way too high.

Click to expand...

word, you should really drop the pH... but you say you water every 3 days? i am sure they can go longer inbetween waterings, remember you want your plants to seek out water(expand) the more you bring the water to the roots the less theyw ill grow, which will eventually you leading to overwatering, cause you see the plant get bigger and think you can water more often...and other than that, you might need to bump up the nutes, i would flush first if you havent already...

Ok so. I have ph down. How much do I use to a gallon of water? That's what I do right put in the water. Then water the plants? What is ideal ph. Should I gradually bring it down? I bought some spring water to flush. How much to use? Do I just water a little more than normal without nuts?

The best flushing water imo and the water we always use for everything is both distilled and filtered bottled water available at Fred Meyer and other stores. For standard soil, you want a Ph around 6.5. Coco coir and hydro systems usually need a lower Ph. You put the Ph down or lemon juice into the water until testing it reads where you want it. To properly grow, you should have both soil and liquid Ph testers. A cheap liquid test kit can be as low as 5$ and soil probes go for around 15$ on up. I always reccomend getting a capsule-type soil Ph test kit for a couple bucks just to verify the probe's reading once in awhile. Remember that testing the soil and testing the liquid are two very different Ph values.

With your Ph being off so much, the best way to go is to transplant into better soil if they can handle it. You then have properly Ph'd soil and can just water & feed at a similar Ph from then on. You can and should flush with more acidic water before transplanting. If you just flush without transplanting, the soil may end up raising the Ph back up over time.

Three parts potting soil, 1-1.5 parts Worm Castings and 1 part perlite is a good basic soil mix. Blood Meal, Kelp Meal and High Phosphorus Guano can be added to the mix to make it even better as long as the plants are big enough to handle the ferts.

Reading this thread realy helped me out!!!!! Just moved to higher ground and the well watter is diffrent all the time on ph, 3 years in and had lots of grate meds. I still get spanked by the basics!!!!!!!!!!!!!!!

One thing to look at is where is the yelowing and brown at on the plant? Is it from the bottom or the top? If it is from the bottom then often you can increase the nutrients as the plant is doing all it can to get the nutrients to the top of the plant. If it's at the top of the plant you may have bigger issues such as bacteria, mites, disease etc.

Looks like you need to up the nitrogen(LIGHT GREEN LOOKING) and lower the P and K. 55 days old should be able to take more than a 1/4 dose.
I grow organic and just use well water and Humboldt organics line. I don't test ph. buffers in soil already. Get great results no headache.