Could Use Some Help Diagnosing a Sativa Problem

[yankeegreen]

I am currently in the 3rd week of flowering a couple sativa doms and an indica dom. So here's my issue: In the past week the leaves of the sativas have been consistently and quickly yellowing and slight tacoing. They are growing in a medium primarily ProMix BX, FF Ocean Forest, perlite and vermiculite. I am feeding Earth Juice line of nutes, currently Grow (N), Catalyst, Bloom (P) and Hi-Brix (K) as an aerated tea. The ph of the tea is ~5.5 and initial runoff is ~6.4. Lights on temp is ~74*F, off ~60-62. All the above applies to the indica which is thriving quite well.

My initial reaction is that it is an N deficiency as the sativas have been stretching quite a bit the last week, but the tacoing has thrown me a bit. Any observations, suggestions, etc appreciated.

Pics added as attachments. Last pic is the healthy indica, same conditions.

Sativa pics



...and healthy indica

 

[RIKNSTEIN]

I would back off the N and concentrate on P & K & cal mag, they don't take alot of N for flowering so it's overload on your fans...good luck...they look good by the way

 

[yankeegreen]

Rink - Many thanks for the response and feedback. So it looks to you like cal and/or mag deficiency? In the past when I have treated for that it presented differently - similar yellowing of the leaves but started on the edges and left dark green veins in the leaves. I'll queue up the Cal-N-Mag but I just fed yesterday so I've got a few days before I can add it to the tea.

 

[Jozikins]

ca/mg is the issue 7/10 times in this stage. I'd start feeding with a lower pH until your run off is closer to 5.9, you may not be getting enough of certain nutrients because your medium's pH range is off a little bit. Add more HiBrix to your mix, molasses will help lower your pH and give more ca/mg to your garden. A ca/mg supplement would quickly remedy the issue, but other issues may arise from your high pH soil. This should also prevent the issue in future grows, hopefully.

FFOF is a "soiless" mix, so we need to keep it in a hydroponic range.

 

[Mohican]

My Malawi started doing this and I tried everything. Then I saw it happen on all of my different clones of this girl. I think it is how they pull the nutes out of the fan leaves when the flowers start to form. I had burnt tips and still had yellow leaves. Went out every day and cleaned them up (bugs are attracted to yellow). At one point I had a big pile of perfect yellow sativa leaves.






I think it is just the way this strain reacts to getting old. I remember an old hippy grower back in the 70's telling me that the plant was done with the water leaves. It does not need the solar panels any more. The cola leaves will start filling in and the buds will swell. Let them go as long as you can. Mine started to rot from the cold wet weather before they reached their full potential.




Compost pile got almost as much as the drying rack:





Cheers,
Mo

 

[yankeegreen]

Good call on the medium ph, it is definitely on the high side - maybe contributing to lockout. I'll make sure I drop the ph of the tea a couple/few tenths before next feedings.

 

[yankeegreen]

Mo - Thanks for the bedtime story, it definitely will help me sleep better tonight! This is the first time growing this strain - Mandala Beyond the Brain - andas you said, maybe its how she rolls. The leaves are supple, not at all brittle. I will definitely work the ph down to a more optimal range and supplement with a bit of CalMag on the next feeding to start.

 

[Jozikins]

I definitely agree that many strains yellow through out the flowering period as a natural part of the growth process, some very excessively. But the death of the fan leaves means the buds have stopped growing, and pretty much all other processes. However, Sativa's are prized for their floating, high energy, happy-go-lucky buzz, and many growers prefer to crop weeks before the buds have put on their final weight to get that desired feeling. I know my Blue Dreams can go between 11-14 weeks if I really pushed them along, but I usually crop at week 9-10, the earliest they are ready. The buds aren't quite rock solid, but very dense still, and my patients much prefer my Blue Dream over other vendors because it does deliver that happy-go-lucky high energy buzz.

I also have a strain I breed myself that is basically leafless by crop time, leaves yellow up early on and just shed like crazy from there on out. And if I let it go to the end the buds will get so dense it will rot on the stem. Depending on pheno I can crop between weeks 6-8, but if I can give the garden the attention it needs, I can go to week 10 or 11 to get the weight. But the buds on this particular pheno are very very dense on the plant, definitely a high yielding commercial crop. I got the seeds out there now, so maybe expect Pakistani Punch in your local dispensary soon, if you haven't already seen it.

 

[70's natureboy]

I guess I grow for color. If I had pale plants like that I would have given them some more nutes long ago. Strains that yellow are just hungrier than other strains imo.

 

[*BUDS]

The ph going in must be 6.5 not 5.5 and this is the reason why your plants are lime green/ yella.

 

[*BUDS]

Same for you, you didn't watch your ph. It looks like they were yellow early and you tried to correct it with extra nutes overshooting which gave you the nute burned leaves. Also looks like some mold in there to.

 

[yankeegreen]

The ph going in must be 6.5 not 5.5 and this is the reason why your plants are lime green/ yella.

When growing in soil I shoot for 6.6. I thought soil less medium should be closer to hydro ph range, no?

The runoff starts at 6.4 and drops from there. My meter puts the medium at 6.6. I was thinking the medium (then microbes) was buffering but maybe way off on that. You thinking the medium be lower ph and the tea higher?

 

[Mohican]

Every time it rained my plants would go crazy. I watered well so I knew it was not for lack of water. So I measure the pH of some rain water and from two samples it was 5.8 and 5.7. Now I ad phosphoric acid to my water to get the pH down to 5.7 when I water.

As for nutes and Sativa strains - I had major burnt tips in Super Soil, Clay, and a roots and pumice mixture. All of these mixes still had the yellowing leaves. The strains were all Holy Smoke 100% Landrace Sativa but different types - Malawi, Mulanje, Mozambique Poison. They exhibited the same leaf yellowing. No amendments stopped it and I am sure when the stems stop stretching the water leaves are done. They relinquish their nutes, turn yellow and drop away. This is when the bud leaves start to fill in and the buds swell. And they swell for a long time!


Mulanje (bubblegum) in Super Soil




Malawi in Clay Soil




Malawi in a trashcan full of roots and pumice




Malawi in Sunshine #4 Blood Meal and Bone Meal and fed Flora Nova Bloom




You are fine and it will be killer smoke


Cheers,
Mo

 

[Jozikins]

Yeah, I agree. Most strains are hungry when they yellow, but just certain strains get ugly while flowering because that's just what they do. I think BUDS might have misread that you are in soiless, not soil. With soiless you are going to use a hydroponic range. Have you considered top dressing with peat to drop your pH? Simple, organic, and removable. Sulfur is there once it's there, not so forgiving.

Microbes can buffer, but you need to build one hell of a colony first. And many of us do little things that kill the colonies when feeding our plants, without even thinking about it. Adjusting tea pH, using synthetic nutrients, using time release fertilizers, or just not starting with the right pH in the first place can kill off or weaken our beneficial colonies. Often, unless we cook our soil for a long time and try not to turn it too much while potting plants, it can take months before your cannabis has a strong enough colony, and could be very close to crop time by then.

 

[yankeegreen]

Yeah, I agree. Most strains are hungry when they yellow, but just certain strains get ugly while flowering because that's just what they do. I think BUDS might have misread that you are in soiless, not soil. With soiless you are going to use a hydroponic range. Have you considered top dressing with peat to drop your pH? Simple, organic, and removable. Sulfur is there once it's there, not so forgiving.

Microbes can buffer, but you need to build one hell of a colony first. And many of us do little things that kill the colonies when feeding our plants, without even thinking about it. Adjusting tea pH, using synthetic nutrients, using time release fertilizers, or just not starting with the right pH in the first place can kill off or weaken our beneficial colonies. Often, unless we cook our soil for a long time and try not to turn it too much while potting plants, it can take months before your cannabis has a strong enough colony, and could be very close to crop time by then.

It may be partially strain related but honestly I think it is more related to deficiency, possibly environmental. I don't have any pics, but when I examined the root balls on the males that got binned, they were very healthy and had a pretty solid myco web developing as well. As far as other micros, I agree that it takes longer than a single cycle to develop the colonies of beneficials which is why I am such an easy sell on the ROLS approach. One tradeoff that I am not crazy about is starting in large pots - my veg room is just not set up to handle too many bigs.

I am going to top dress at lights-on with EWC and bone meal and wet with a molases solution. This should give a bump of nitrogen, phosphorous and carbs. Do you think I should hit with Can-N-Mag as well?

 

[Jozikins]

You will not need any Ca after top dressing with EWC. Molasses will give you all the Mg you will need to go with it. You can mix in peat to help drop your pH too. EWC top dressing also keeps the soil crawlers away!

It's good to know you seem to already have an abundance of gardening knowledge, cuts back on how much I have to type, lol. Not familiar with ROLS, I'll look into it. I don't normally go larger than 2 gal max in my veg room, unless I'm doing a final transplant before 12/12. I'm fortunate enough to have a large sun room that I use for anything larger, I just pop them under supplemental light until I get 14 hours of sunlight.

 

[yankeegreen]

You will not need any Ca after top dressing with EWC. Molasses will give you all the Mg you will need to go with it. You can mix in peat to help drop your pH too. EWC top dressing also keeps the soil crawlers away!

It's good to know you seem to already have an abundance of gardening knowledge, cuts back on how much I have to type, lol. Not familiar with ROLS, I'll look into it. I don't normally go larger than 2 gal max in my veg room, unless I'm doing a final transplant before 12/12. I'm fortunate enough to have a large sun room that I use for anything larger, I just pop them under supplemental light until I get 14 hours of sunlight.

Really appreciate the benefit of your experience...that goes to all who have responded in my time of need! I will go with the top dress as described.

As far as ROLS, it stands for Recycled Organic Living Soil and is as much a philosophy as process. Not one to drink the Kool-Aide too fast but it definitely has some intuitive benefits, but as with anything there are trade offs. Basically, its a no-till soil approach where you use a large pot/bin of composted soil and use it for several generations of growing by just top dressing. Harvested plants are cut off at the stem and new seed/clone is planted next to it. New growth can take advantage of the established micro colonies, myco web, etc. Here's a link to a thread on RIU.

 

[Jozikins]

Good stuff! I have PM and rot issues in my area. I've made sure to ask around, it's not just me, lol. I don't think this method will work for me, but I'm pretty good about saving all my outdoor and indoor flushed soiless mix and throwing it into a large compost heap, which I amend with organic fertilizers biannually. I don't break apart the rootballs, on a few of those grows I really put a lot of effort into establishing some amazing colonies. I usually have more than I can grow with outdoors, so it builds up some good stuff overtime. To be honest though, I've been MIA for about a year and a half from this grow so it hasn't got the normal amount of love it usually would lately.

 

[yankeegreen]

Well a week later and I am definitely seeing some improvement with the boiled bone meal tea and bone meal + EWC top dressing. The sugar leaves have responded the most/quickest and some of the fan leaves are slowly darkening though I have written-off some of the fan leaves. There continues to be some stretch but it has definitely slowed in week four. Bud development does not seemed to have suffered.


One week ago / tonight side-by-side:



Doesn't seem to have impeded bud development:

View attachment 2622035 View attachment 2622037 View attachment 2622038