Need help please- My sativas are yellowing, dying leaves

[booger]

This could be long, but I want to give as much info as possible to help diagnose.
The particulars:
1. Soil grow- MG Organic (no nutes), perlite, vermiculite mixed, on top of 2" of rock base
2. Germinated 10 seeds (5 jock horror, 5 haze) 9 sprouted however 5 only made it.
3. 3 haze (2 good sized, 1 runt), 2 Jock Horror
4. Small grow area (3 x 3) partitioned off in a very large room. Lots of ventilation including an oscillating fan.
5. Temperature in grow area ranges between 82 - 87. Humidity from 35% - 55% depending on time of day.
6. Seedlings planted on July 29 (5 1/2 weeks old)
7. Originally started with 400w HPS set approximately 32" away (used on seedlings) At 4 1/2 weeks, I added approximately 165w of mixed CFL's
8. Today, I removed the HPS, and replaced it with 400w MH (I noticed the CFL's really jumped the growth and decided to switch to MH trying to get more blue light)
9. Originally I was on a 24/0 lighting schedule. After week 2, I changed the schedule to 18/6
10. Water schedule- every 2-3 days for the small seedlings. For the last 2 weeks, I have watered every 5 days

Well, the Haze took faster than the JH, but I attributed that to different strains. The JH has struggled from the start, but I felt it would eventually pick up. Around week 2, I gave the seedlings light nutes (25%) of Peters 20-20-20. Within a day, I quicly learned that it was a bit too soon and I had slight burning of the very tips on 1 haze and 1 JH. So I did not give it anything but water for the next 2 1/2 weeks.
About week 3, the lower leaves began to have a uniform yellow. I suspected nitrogen deficiency, but held off for another 2 weeks to be safe. Instead, I gave them some epsom salts. The ph was a tad on the high side (7.0) and thought it wouldn't hurt.
Approximately 1 week ago, the Jock Horror took a turn for the worse and very quickly the lower leaves turned brown and flaked away. There is still significant new growth coming from the lower stem where the leaves died.
About 2 days ago I noticed the lowever leaves of the haze have begun browing and becoming crispy. I decided to give them some nutes (50% - 1/2 teaspoon per gallon) to try to pick them up. I also added some worm castings to the soil and fish emulsion to the lastest watering.
Please take a look at some photos and let me know what you think I need to be doing.

 

[Nico]

Things to check

1. Ph..
2. Humidity and Temperature seems ok
3. Try a Organic fert with a higher N content. Some have sub nutes as well. Maybe a N shortage
4. Check that they are not drying out, but dont overwater.
5. check for good air circulation plants need co2.

Best of Luck

Nico

 

[boardercross91]

the same exact thing is happening to mine. im using the mg organic, was doing great, and then i added another cfl and bamm, my bottom leaves are dying anf im not sure whats causing it? i thought it was heat stress, but its my bottom leaves, and my top leaves are good, very healthy, im lost? if you find out whats wrong with yours please let me know, my leaves are almost identical to yours. i dont want to lose my babies, im about to transplant to a fresh pot of soil, it might be what they needed?

 

[Growdude]

Plant looks hungrey, give them some time to see if the nutes and worm castings help.
The yellow lower leaves will not green back up but new growth should look good .

 

[Mutt]

I agree with Nico looks like an N def.
But would double check the PH run-off just to make sure. 7.0 is borderline...but have grown just fine without lock-out at that level. prefer lower...but hey sometimes it is what it is. If it ain't broke......

 

[booger]

Thanks all. I appreciate the quick response.

Boarder, I followed your thread, and saw the similarities as well. Let's keep in touch.

Basicaly think I burned them when they were babies, and then when they took off, I failed to give them anything for fear of doing more damage. I'm going to try to be patient and make small adjustments. I wouldn't be so calm if I didn't have new growth coming from the lower part of the plant.

 

[boardercross91]

yes, thanks, i dont think i burnt mine at all yet, ill change the soil and check my ph, but i have shut the cfl off for now and will be seeing what changes i see now. anyways, my other plant looks great, so im not sure what it could be, but who knows. im not going to jack your thread so if you get your plants looking better, please let me know what you did?

 

[jash]

yes, thanks, i dont think i burnt mine at all yet, ill change the soil and check my ph, but i have shut the cfl off for now and will be seeing what changes i see now. anyways, my other plant looks great, so im not sure what it could be, but who knows. im not going to jack your thread so if you get your plants looking better, please let me know what you did?

dont think that the light is causing problems(your other plants doing well)light is never enough

 

[booger]

Update.
Hungry, hungry plants. Adding the worm castings, fish emulsion, and giving them a dose of all-around nutes has picked them up. They're greening up nicely in just a few days.

I've heard nothing but good things from a grower frined about fish emulsion. What are all your thoughts on it?

 

[The_Duhcider]

Fish is ok. Earth Juice is what I prefer, be sure to use E.J. Catalyst with your grow or bloom as well ... If you're foliar feeding, be sure to wet the undersides of your leaves, as this is where the stomata are located, which is where your leaves will take in any foliar fed nutes.

 

[The_Duhcider]

ps. be careful when foliar feeding...I'ts much aeasier to burn a plant that way...