New grower needs help!! Nutrient Burn or heat stress?

[Uncle T]

Hey everyone,
I need some help. This is my second grow. Last year I used poor quality soil and needed to feed them a lot. This year I used Fox Farms soil and it seems to be running hot with nitrogen, but I'm a newbie, so it could be many things. Here are the details of my grow...
- Fox Farms soil, in 5 gallon pots
-Grown outdoors, (but I bring them in at dusk and keep them under flourescents on a timer so they get a full 18 hours of light and don't flower early.) I had this problem last year, and a few of my plants flowered early this year too.
-They haven't been fed any nutrients yet.
- I use PH down to bring the tap water down to 6.5-7.0 when I water.
-It gets hot where I live (Northern California, near Sacramento) 90-100 degrees
-I am growing several different strains, all bagseed, none are from seed banks. One is from Humboldt, one is Afghani, and the other are Northern California Hybrids. The Nor Cal hybrids seem to be the most sensitive. The Humboldts seem to be the strongest.
-They are 9 weeks old and average height of 2-3 feet.

Hopefully some of you can help. I can't afford to buy MJ and I depend on it medicinally, so this grow is very important to me.

Here's my problem. It looks like I have nutrient burn, but from all the reading I've done, it could be a nutrient deficiency. I don't want to compound the problem and make it worse by doing something wrong. I have heard a few people say that the Fox Farms soil runs hot with nitrogen, so my thinking is that it is nitrogen burn. The plants grow vigorously and are very green, and then suddenly develop spotting on the fan leaves on the middle of the plant. Since it looks like nutrient burn, I flush them, and it seems to help, but it just happens again in a few weeks. Is the soil too rich in nitrogen? I asked some of the local growers and they said to just keep a close eye for the spotting, and as soon as I see it, flush the soil.
Do you agree with this? Or do you have another possibility? It seems like I have to just keep watching the babies and when they get spotty, flush them, but I am also flushing away nutrients that they need, which makes me think I'm causing nutrient defiencies at the same time.
Also, it seems like the nutrient burn happens when the outside temperatures get above 85 or 90 degrees. I built a shade cover with some shade cloth, and hopefully this will help on the extreme hot days.
Does Nitrogen get more active in the plant when the temperature raises above 80-85?
The spotting turns to yellowing, which turns to crisping of that area of the leaf.
Also, you can see in one of the photos the leaves are folding up like a taco, what could be causing this?

 

[Uncle T]

Here are a few photos. These are from 2 different plants that are having the same symptoms, but if you look at the second photo and see that the stems are purple, that is just the strain, not a deficiency symptom. It has grown purple from day one.
Also isn't nitrogen deficiency usually a uniforn yellowing of the leaf, starting at the bottom of the plant?
I had 2 plants flower early, they were then given "Open Sesame" Fox Farm fertilizer, which is a 5-45-19 and I stopped bringing them inside under the light at night. One that was spotting and I flushed is no longer spotting. Maybe this info could help in the diagnosis.

 

[kingk]

Here are a few photos. More to come.

Well, the first thing is.Does it spot rapidly.Does it happen over a course of hours in in just 1 to 6 hour period, then you have heat problems but if it spots slower over a course of days then you got nut burn.

 

[kingk]

if i was you i would flush it every day for at the least 3 days

 

[Uncle T]

Thank you so much for the speedy reply. It happens over the course of several days, I can see it coming. It starts with the leaves on the upper portion of the plant looking like they have very faint yellow spotting. I either flush it or let it go another day and see what happens. Even if I do flush it, it seems to continue for another few days before it stops affecting the leaves. It continues to the point of the burnt leaf photo I posted. Then it stops, grows well, then a week or two later, it spots again. But I've never flushed it for 3 days, how much water should I be putting through these 5 gallon pots when I flush?

 

[Where in the hell am I?]

It could also be a nute deficiency! It is DEFINITELY a good idea to flush, tho I would only do it 2x's, then wait till she needs water again and give the appropriate EVERYTHING, also, hit her w/B-1 in between the 2 flushes

 

[Uncle T]

Thank you.
Give her B-1? Is this something I can get at the nursury? Straight B-1 or is there a fert that has it in it that you would recommend?
Also, should I flush the girls that are doing well now to prevent this? Is flushing just something I should do every few weeks regardless of over-fert symptoms? I've read very different opinions on this one. Some say flush every 2-4 weeks even if there are no problems. Maybe that would have prevented this?

It could also be a nute deficiency! It is DEFINITELY a good idea to flush, tho I would only do it 2x's, then wait till she needs water again and give the appropriate EVERYTHING, also, hit her w/B-1 in between the 2 flushes

 

[The Warlord]

If you've never fed them anything it's certainly not nute burn. FF soil only has enough nutes for 1 month or so.....

 

[Uncle T]

They had this problem in the first few weeks. When it eases up, I transplant into fresh soil with new nutes available. They have been transplanted within the month so that should have another 30 days after transplanting of nutes. It seems like they burn just about two weeks after the transplant. Maybe that's when the nutes in the soil become most active? The guy at the nursery said other guys were coming in with the same over-fert problem with Fox Farms soils, so they were mixing it with the Happy Frog soil conditioner to ease up on the nutes. Plus I have seen N deficiency and the plants don't grow so fast and look so green when they are N deficient. I'm just wondering if flushing out the overload of nitrogen I'm also flushing nutrients that it's not overloaded on, and I'm depleting those nutes.

If you've never fed them anything it's certainly not nute burn. FF soil only has enough nutes for 1 month or so.....

 

[KAL EL]

The leaves looking like tacos is from it being too hot.

By chance, are you spraying the leaves when you water?
Are you watering during the heat of the day?
It almost looks like the spots could be from water droplets magnifying the sunlight on the leaves on some pics.

 

[Uncle T]

The heat is causing the taco effect? Is it only happening on that plant due to it being a different strain? The sativa dominants seem to do this more than the indicas.
I water first thing in the morning, at about 7am. I sometimes mist them in the evening with a mister. But never misted in the sunlight.
Thanks for everyone's helpful replies!
Everyone is SOOOOO cool here!!!!
They are looking like they have so much potential, I would hate to see anything happen to them.

The leaves looking like tacos is from it being too hot.

By chance, are you spraying the leaves when you water?
Are you watering during the heat of the day?
It almost looks like the spots could be from water droplets magnifying the sunlight on the leaves on some pics.

 

[Where in the hell am I?]

Ya can pick up a bottle of B-1 almost any where that has anything fer plants and it is CHEAP!!!