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Deficiency? Light Burn? Thoughts/Tips

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#1 HailHypnoToad



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Posted 07 December 2016 - 10:33 PM

Hey All,
This will be my first -post about my first attempt at growing Cannabis indoors. I feel i may have put my plants under some undo stress in the beginning as i was all too excited to give them the light they require.

I started with Clones under a 300 Watt LED (KING LED Brand) 12 in from the top of my plants and in my small veg tent the temperatures soared to 89 degrees. I kept them under the LED for another two days while managing the temperatures with an exhaust fan.

I started seeing discoloration in some of the larger fan leaves and browning on some of the newer growth. I assumed lightburn and have since kept them under a 2ft 4 bulb T5 panel. I have been keeping them on an 18/6 cycle. However in the past two weeks i have only seen minor improvement with new growth and still my fan leaves are yellowing and browning. (See Pictures)

My questions are thus:
For the 5 Plants i have now, is the lighting i am providing adequate? ( I was thinking about getting another 2 ft 4 bulb panel) Should I maybe go with CFL or HID MH?

Could this issue be a lack of nutrients?

My Humidity is hard to maintain and is consistently in the low 30's, i mist 3 times daily! Any easy recommendations before i go out and buy a humidifier?


Any thoughts or opinions would be greatly appreciated.

Attached Thumbnails

  • Locomotion 2 weeks - Browning 4.jpg
  • Veg Tent week 2.jpg
  • Locomotion 2 weeks - Browning 2.jpg
  • Locomotion 2 weeks - Browning.jpg
  • Locomotion 2 weeks - Browning 3.jpg

#2 PsyBearknot



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Posted 08 December 2016 - 07:57 AM

I bought a "clone tent" set up with a 50w led. I was not sold in the 50 w but the price for the tent set up was good. The clones were not happy. Not sure what the issue was could have been the heat in the little tent but I switched back to t5's. I have a 2 bulb t5 that I use for small clones or seedlings. I can fit 6 beer cup size plants under it no problem and I keep them 8-12 inches from the lights. I keep there 24 hrs for 2 weeks. Then into a veg tent under 4 ft 6 bulb that covers a 2x4 well. That's around 400w. 600w how with some LED supplementing in flower

I think your clones are maxing out your light space with that 2 ft in my opinion but still a little new with canibus.

You can add another 2 ft 4 bulb and not have a problem but I would not add if you can still fit the 5 plants under the current one you have. Might also price out the 4 ft fixtures. Most places a 8 bulb 2 ft is almost the same price as an 8 bulb 4 ft. 2 - 2ft units are also 2x the bulbs you have to buy.

T5 does not give the spread of light penetration that mh/hps does. So anything over 12 in bed and your loosing penetration. So great for smaller plants and clones and Scrog set ups.

I have successfully grown kale, chard and spinach under correct spectrum household CFL's but once you get enough bulbs for light the heat builds up quick too.

I control heat easily with 6 inch fan filter comb in a 2x4 tent with 600w ups and 2 100 w led spot type lights. No smell with 6 plants in flower.

I'm still new but that looks like heatstress / light burn.

Edited by PsyBearknot, 08 December 2016 - 08:00 AM.

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#3 Myc


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Posted 08 December 2016 - 10:25 AM

My .02:


Your lighting scheme looks good. 


I had the exact same problem while using those plastic pots. The problem turned out to be anaerobes in the soil. 


If you lift one of the root-balls (gently separate and slip out the plant from the pot) you may notice that the root zone near the sides and bottom is withering and turning brown or beginning to rot. 

Use cloth pots. They breathe. Anaerobes can't tolerate fresh air exchange. 


When transplanting, one should do a root pruning. Simply lift the root-ball and score it with shears or other sharp blade 4-5 times. This does the same thing as "topping". The roots will double down from all of the injured sites just like a vegetative branch doubles when topped. I hold the plant by its stem and score the root-ball - cut about 1/4" deep from the soil surface down to the bottom of the root-ball in a straight line parallel to the plant stem. 

Hold off on any fertilizers or concoctions until the soil has had a week to recover. A teaspoon of epsom salts in 3 gallons of water is a good transition mix. Then, only slowly begin feeding. Ease into it. The longer the plants vegetate the better the final outcome. 


My best guess. 

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#4 HailHypnoToad



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Posted 09 December 2016 - 05:37 AM

Awesome thanks all!

I have 5 gallon grow bags for my final transplant. (and just purchased 1 gallon bags for my dixie cup transfers)



How can i know for sure when to re pot? and is there a way to check for root rot before i go to transplant?


Due to the small size of my veg tent 24" by 36" by 48" and low light output should i move to my unoccupied flower tent (36"x36"x72) and put them under my LED's (2x 300 w KING LED) on the veg cycle for a few more weeks before i set them to flower (w/ 600 Watt HPS)?

#5 JanSteen



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Posted 12 December 2016 - 12:58 PM

You know for sure when to repot, when you repot. Weed is the easiest and most forgiving plant in the world. Just be careful to let the soil dry a little before repotting, since wet soil would break off and tear the roots apart. Root pruning is something for bonsai plants and seems something aesthetic to me, normal cannabis plants root perfectly fine on their own. There is no need to cause damage and stress if they are behaving just fine. Damaging plants on purpose, just because people think that good rooting isn't good enough, seems to me like plain boredom. Roots grow from the tips only, and have a hard time recovering from damage. Clipping the roots will put your grow back by a week time. I usually repot when the height of the plant equals the diameter of the pot. But it depends a lot on if I feel like repotting that day. The issues on the pictures seem to be caused by something overheating locally. Which seems more plausible since nearly every damaged leaf is close to the lights. Root issues would destroy the entire leaf within days, and it would not cause random dry brown spots. Plants with root issues look withered as well, and yours doesn't. Anaerobic soil bacteria, those are the ones you want. Together with some aerobic ones. If you have strictly anaerobic ones, you're over-watering. A good soil is airy on its own, since you shouldn't compress it. And that allows for both anaerobic and aerobic bacteria to thrive. If you do compress the soil, the plant will be hindered much more by the tough, dense soil holding too much water, than anything else. It seems that comments over here now have become conflicting.. I trust my 12 years of experience with growing MJ. But as with any information, it's great to google around a little. There are a million and one ways to grow cannabis, and all of those techniques are the best according to the ones using them. I've been helping people grow since the past 8 years, and I noticed that it's pretty hard to kill cannabis when you just use the most common general guidelines.

#6 Hash_Man


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Posted 12 December 2016 - 07:35 PM

I didn't pay so much attention to the previous posts, so sorry if I repeat something someone said.
Most of what I'm seeing is magnesium deffiency .. when you said " ...i have only seen minor improvement with new growth and still my fan leaves are yellowing and browning..." that would be typical, Magnesium is mobile. It's also typical the tip burn with yellowing between the veins along with the burn
There's different ways to solve it but I'm suspecting if your using good soil (looks like not) and/or adding CalMag you might want to be sure your pH isn't out of control. I ussally have an idea if mine is one way or the other and adjust higher or lower the next feeding or watering for two weeks or so .. but that being said bro, and I might be mistaken but their looking like they are staying too wet (most your leaves are krinckly) your soil doesn't look like it can dry out, they really need air man


EDIT: Yea, what myc said

Edited by Hash_Man, 12 December 2016 - 09:26 PM.

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