Help With Yellowing Leaves

[Stratbot]

Been around looking at posts for a while as a guest. Joined a while back. This is my first grow. I'm in Roots Coco using a Technaflora starter pack for nutes. On day 29 of flower. Feeding every day with a minimum 20% runoff. All was going well until I see yellowing on the leaves of the bottom of the plant and now starting to work its way towards the top. I have a very high EC 2.9-3.0 in the runoff with a runoff pH of 5.9. In veg, worked my way up to an EC of 2.0 (as recommended by Technaflora). Flipped to flower and had some clawing and slight burning of tips of a few leaves. Cut nutes back and flushed with 0.9 EC due to concern of high EC runoff. Runoff lowered some but I still had high runoff EC. Don't know if I flushed enough. I am not doing the feed, water, water sequence as recommended by Technaflora. Using RO . Under a T-5 flouro. Below is what I've seen/watered the past number of days. Any help is much appreciated.

RH: 36-49
pH: 5.5-5.9
Air Temp: 66-79
EC: 1.0-1.4
Water Temp: 69-71

pH EC Day
5.5 1.0 16
5.9 1.1 17
5.6 1.1 18
5.7 1.1 19
5.6 1.0 20
5.8 1.3 21
5.6 1.3 22
5.5 1.3 23
5.5 1.3 24
5.8 1.4 26
5.9 1.3 27
5.8 1.4 28

 

[Pot Boy]

Cal mag bro should get you back on track...

 

[Seamaiden]

Been around looking at posts for a while as a guest. Joined a while back. This is my first grow. I'm in Roots Coco using a Technaflora starter pack for nutes. On day 29 of flower. Feeding every day with a minimum 20% runoff. All was going well until I see yellowing on the leaves of the bottom of the plant and now starting to work its way towards the top. I have a very high EC 2.9-3.0 in the runoff with a runoff pH of 5.9. In veg, worked my way up to an EC of 2.0 (as recommended by Technaflora). Flipped to flower and had some clawing and slight burning of tips of a few leaves. Cut nutes back and flushed with 0.9 EC due to concern of high EC runoff. Runoff lowered some but I still had high runoff EC. Don't know if I flushed enough. I am not doing the feed, water, water sequence as recommended by Technaflora. Using RO . Under a T-5 flouro. Below is what I've seen/watered the past number of days. Any help is much appreciated.

RH: 36-49
pH: 5.5-5.9
Air Temp: 66-79
EC: 1.0-1.4
Water Temp: 69-71

pH EC Day
5.5 1.0 16
5.9 1.1 17
5.6 1.1 18
5.7 1.1 19
5.6 1.0 20
5.8 1.3 21
5.6 1.3 22
5.5 1.3 23
5.5 1.3 24
5.8 1.4 26
5.9 1.3 27
5.8 1.4 28
View attachment 457375 View attachment 457376

Ok, in my opinion your RH is far too low. I also think you're keeping the pH parameters in the wrong range, my experience in coir says it should be 5.8-6.2, with 6.0 usually being THE sweet spot for most strains.

I don't know anything about the nutrients you're using, and I don't use run-off parameters to help me solve problems. I could also REALLY use more and more better pix.

What you're showing doesn't look like a plant at day 29 of flowering to me, it looks a bit behind that timeline. The feeding pH and RH/temp parameters could be part of the reasons for that.

You don't mention what you're using to account for Ca and Mg (calcium and magnesium, respectively) and since I'm not familiar with that nutrient line those minerals may already be accounted for, but just in case you're not aware, coir locks (adsorbs, IIRC) onto calcium and magnesium in a really big way, and those two minerals are very important players in nutrition.

Can you get more pix? Whole plant, and better showing this yellowing from the bottom up you're describing (which sounds like they ran out of N)?

 

[Stratbot]

Cal mag bro should get you back on track...

Thanks for the reply Potboy. Using MagiCal but you may be right as when I cut back the nutes I also cut back cal mag. Will try to correct.

 

[Stratbot]

Ok, in my opinion your RH is far too low. I also think you're keeping the pH parameters in the wrong range, my experience in coir says it should be 5.8-6.2, with 6.0 usually being THE sweet spot for most strains.

I don't know anything about the nutrients you're using, and I don't use run-off parameters to help me solve problems. I could also REALLY use more and more better pix.

What you're showing doesn't look like a plant at day 29 of flowering to me, it looks a bit behind that timeline. The feeding pH and RH/temp parameters could be part of the reasons for that.

You don't mention what you're using to account for Ca and Mg (calcium and magnesium, respectively) and since I'm not familiar with that nutrient line those minerals may already be accounted for, but just in case you're not aware, coir locks (adsorbs, IIRC) onto calcium and magnesium in a really big way, and those two minerals are very important players in nutrition.

Can you get more pix? Whole plant, and better showing this yellowing from the bottom up you're describing (which sounds like they ran out of N)?

Hey Sea,

I knew you'd be the one to come to the rescue. I'll try to provide more info shortly. The flush and feed I did yesterday seems to have had some affect but maybe to early to see.

My RH over the last 24 hours was 58/45 range. What's my goal? I'll also start shooting for the 6.0 pH number. As far as nutes, I just purchased the Canna Coco line and will use that on my next run. For now, I'm going to finish with what I have. Don't want to change in the middle of the grow. Related to the timeline, I'm going to end up with popcorn so I hope learn from my mistakes. Using a T5 8-bulb 24" for lighting is not where I need to be. I was not really set up when a friend gifted me two clones. So I tried to make due with what I have. Can you say Stretch? Next time, better lighting and nutes. Still so much to learn. I am using MagiCal for Ca/Mg but when I cut back on EC level I also cut back on the % of Magical and that may have caused the issue. My Camera sucks so I'm not sure I can provide much better pictures. I'll see what I can do. I really appreciated the help. My good intentions don't seem to be turning into good product! But I'll keep plugging along. I read so much stuff here sometimes it's confusing and other times I can't keep it stored in my brain.

Thanks for the comments.

 

[Seamaiden]

Definitely, keep working on it! You learn as much, if not more from your mistakes as your successes. Drop the T5 down closer onto that girl. Add some red spectrum bulbs for flowering. Up the MagiCal because once you go into a Ca- you won't be able to recover. If you can, add more lights, even CFLs stuffed in where they can fit will be helpful (again, look for more red spectrum, warmer bulb, around 4,000K or below. 5,000K and up is too blue).

As for the RH, that's really as much a function of your temps as anything else. Use the charts for VPD (vapor pressure deficit) that folks have posted in my thread The Charts to figure out where you should be.