Purple leaves and salt build up and bears, oh my!

[Fairly Sterile]

Long time toker, first time grower. My state just legalized home growing in August 2023, so I took full advantage! Unfortunately, I’m a newbie, so I am having some issues and could really use some expert opinions on what is going on.

The pictures I have posted are very recent. I switched to 12/12 lighting 4-1/2 weeks ago. I’ve given as much information as I can, but if you just want to get to the issues and questions, that is bolded at the end of this post.

Strain: Fatso OG (started with rooted clones)

Setup:
Gavita Pro 1700e LED
Gavita UVR LED (UV-A supplemental light) (x3)
3-gallon black fabric grow pots (x4)
Vegetronix Moisture Sensors
Medium: Fox Farm Ocean Forest
Water: Reverse Osmosis remineralized with Organic Cal-Mag by TPS Nutrients (my tap water is awful, so this is necessary)
Vegetative Fertilizer used after ~1 month in the Ocean Forest: Fox Farm Grow Big
Flower Fertilizer used: Fox Farm Tiger Bloom
pH Meter: PINPOINT by American Marine Inc. calibrated before each use with Biopharm reference solutions
pH adjustments with pure, food-grade sodium bicarbonate and citric acid
TDS Meter: Extech EC400 ExStik calibrated before each used with Biopharm conductivity standards
Lasko 16”, 3-speed oscillating fans (x2)
Sealed grow room
Hygrostat controlling dehumidifier and humidifier
Thermostat controlling air conditioner and oil heater
CO2 meter and dosing system
Mylar reflective coverings on all walls

Books I’ve been referencing:
The Cannabis Grow Bible, 3rd Edition
7 Steps to Grow Cannabis

Growing techniques:
-I started the clones in 1-gallon fabric pots and transplanted them once they approximately doubled in size
-Mainlining: Once the clones grew out to 6 nodes, I topped them to the 3rd node and removed the 1st and 2nd nodes. Then, once the two remaining branches grew out to 4 nodes, I topped each down to the 3rd node and removed the 2nd node. I kept lightly training them with plant ties to attempt to get all 8 shoots to a similar height.
-The day I switched to 12/12, I pruned all growth on the bottom third of the plants.
-I maintain CO2 levels at approximately 1400 ppm throughout the entire grow.
-When the plants were young, I kept the light 36” from the canopy. Once they were well established in the veg stage, I kept the light 24” from the canopy and have maintained that since.
-I used a lux meter and followed this guide for light intensities for the different stages (I’m currently at 100% light setting on the Gavita controller): Choosing LED VS HPS Lights - 4trees Cannabis Building
-I started the supplemental UVA lights once the plants were well into the vegetative stage
-I water every 2-3 days after the soil has mostly dried out but just before the plants start wilting. I overfed early on, but now I am being much more conservative and only feed every other watering.

What I know I’ve done wrong and have been trying to correct:

• When I started, I had a cheap TDS meter from Amazon that was giving me bad readings. This led me to add way too much cal-mag to the water (this became obvious when I purchased the Extech TDS meter and calibrated it) for much of the vegetative stage.
• I also mistook the early signs of nutrient burn as what I thought were nutrient deficiencies, so I kept adding more fertilizer and overfeeding through much of the vegetative stage. Once it finally became obvious that what I was seeing was actually burn, I started cutting way back on nutes.

Recent Feedwater/Runoff numbers:

Date	Water pH	Water TDS (ppm)	Runoff pH	Runoff TDS (ppm)
9/14/2023	5.78	1147	6.25	2025
9/17/2023	5.97	189	6.7	1147
9/21/2023	5.92	908	6.54	1850
9/24/2023	5.91	272	6.94	1191
9/26/2023	5.87	269	7.02	1197
9/29/2023	5.73	1077	6.57	2075
10/2/2023	5.83	1288	6.53	1768

Concerns:
-Leaf discoloring: my biggest concern is the discoloration that is continuing to get worse. It started as purpling on leaves closer to the top of the canopy (not all leaves). The purpling started at the edges of the leaves and moved its way in. Now, as it’s getting worse, some of the leaves are turning red. My searches online and through my books don’t seem to give a good answer for purpling at the edges of the leaves, so I’m pretty confused.

-Runoff ppm: My runoff ppm lately is coming out higher than the water I’m adding to them. From what I can tell from my research, there may be a buildup of salt in the soil, which would make sense, since I know I was adding too much cal-mag early on.



Questions:
-What is this discoloring telling you? I’m new to this, and I’m worried I’m still either overfeeding or underfeeding. I’m just not sure which. Or could it be from salt buildup in the soil?

-Should I flush the soil with pure water to remove salts, or will that disturb the plants since they are so far into flowering (but obviously not done—I believe they need 3-4 more weeks from what I’ve read)? Or should I just let them ride it out at this point and only flush at the end, right before harvest?

-Should I trim “problem” leaves? During the veg stage, I would trim off any leaves that were heavily discolored so the plant could focus energy on new, healthy growth, but do you all do that in the flowering stage too? Or do you just leave them until harvest, regardless of discoloring?

-For the next grow, should I plant in 5-gallon pots instead of the 3-gallon pots this time?

 

[Absorber]

It wouldn't hurt to do a flush with straight water to lower the build up of salts ,
They are looking pretty good.
Someone else is bound to chime in aswell.

 

[Fairly Sterile]

It wouldn't hurt to do a flush with straight water to lower the build up of salts ,
They are looking pretty good.
Someone else is bound to chime in aswell.

Thank you Absorber!

 

[Regrowth]

Welcome to the community @Fairly Sterile.
You're doing awesome for your first grow. Seriously...
I can tell you've taken time to learn and master things and miles ahead of where I was on my first grow lol.

-What is this discoloring telling you?
I'm not great with diagnostics but it could just be something the strain does naturally. Sort of like plants do in the fall.
But I prefer not to give advice about things I'm uncertain about lol.

-Should I flush the soil with pure water to remove salts
Flushing can help solve lockout / salt build up but when done at the wrong time it can often -
just make problem worse. If you do flush, make sure to get some nutrients back into the media asap.

A lot of people here skip on the preharvest flushing because it has been found to have little effect. [1][2]
You can do water only for the last week if you want to save some nutrients for your next grow.

-Should I trim “problem” leaves?
Besides solar panels, the leaves also act like storage silos and when there's a need for nutrients the plants will leech food from them. If you remove the leaves with issues usually other leaves will start showing issues instead so it's better to try to identify and solve the nutrient demand first. Defoliating stuff below the canopy that won't get good lighting or may constrict airflow is fine. The plant will kind of do that on it's own in some cases.

-For the next grow, should I plant in 5-gallon pots instead of the 3-gallon pots this time?
Either is suitable. I've used 3 gallon pots instead of 5 for the last few grows and found they perform just as well and meet my needs. Like I said those plants look great... just wait until they swell. IMO the the key to big buds is lots of water. Share some pictures in a few weeks, I'd love to see them again. Cheers.

 

[Sueet]

Tiger bloom is not enough alone, it is part of a multi-bottle feed system. I haven't used it myself, but I believe it is 3 bottles minimum, up to something like 9 but that's probably best left to folks with a lot of experience.

Your plants are hungry, and almost certainly especially for the things in the other bottles. At the very least, find the feed schedule and give them both the grow big and the tiger bloom according to schedule. (not sure what the third one should be, but it will be on the schedule)

 

[013]

Sueet is right Fox Farms requires 3 bottles minimum and IIRC that still doesn’t cover the cal-mag needs.

overall plants look really good, the red shades are nothing to be concerned about but the green appears a bit light… this is the final push in flower and the plant is hungry….

I’m not a fan of flushing but it can be beneficial in certain situations, however you have only used 1 of 3 required nutes. In your case I think flush is the opposite of what you need, they look hungry so why wash nutes down the drain?? However if you do choose to flush then you need to immediately feed as in hit them with a stronger dose of nutrients…right away. They need some N but higher dose of P&K

nope don’t trim fan leaves, not only are they solar panels but those fans are used for transpiration plus storing nutrients, let the plant suck those leaves dry until they fall off naturally

measuring runoff means nothing… if you chase runoff ph you will crash and burn. You only need to be concerned with the ph of liquids going in.

your setting your ph wrong…. you should be at 6.3 going in since you are running in soil. The ph 5.8 range is for coco, hempy and hydro…

In summary… since you are going in with too low PH those nutrients are not available to your plants which is why they are light green and hungry. There are a few one shot does it all nutrients like MC or Geoflora but FF is not a one bottle solution…. you need the other parts of Fox Farms to complete the line up, you can surf for FF feed chart

if that’s concrete slab underneath then I’d get a pallet or two under them for your next run… cold feet can defs be an issue

best of luck- keep us posted

 

[013]

wanted to add….

you’ve done an amazing job here- seriously your plants look top notch, plus you did one heck of a thorough write up above.

over time you will gain experience and confidence. at first it seems sketchy but most of us add nutes very frequently in flower. So right now you are doing feed, water and that’s as it should be, but later on you can bump to feed, feed, feed, water for your next grow cycle if you feel comfortable.

also you can modify the wet dry cycle so you are feeding or watering more frequently in flower cycle. the wet / dry is mostly intended to build roots in veg…

welcome aboard Fairly Sterile!

 

[Fairly Sterile]

Welcome to the community @Fairly Sterile.
You're doing awesome for your first grow. Seriously...
I can tell you've taken time to learn and master things and miles ahead of where I was on my first grow lol.

-What is this discoloring telling you?
I'm not great with diagnostics but it could just be something the strain does naturally. Sort of like plants do in the fall.
But I prefer not to give advice about things I'm uncertain about lol.

-Should I flush the soil with pure water to remove salts
Flushing can help solve lockout / salt build up but when done at the wrong time it can often -
just make problem worse. If you do flush, make sure to get some nutrients back into the media asap.

A lot of people here skip on the preharvest flushing because it has been found to have little effect. [1][2]
You can do water only for the last week if you want to save some nutrients for your next grow.

-Should I trim “problem” leaves?
Besides solar panels, the leaves also act like storage silos and when there's a need for nutrients the plants will leech food from them. If you remove the leaves with issues usually other leaves will start showing issues instead so it's better to try to identify and solve the nutrient demand first. Defoliating stuff below the canopy that won't get good lighting or may constrict airflow is fine. The plant will kind of do that on it's own in some cases.

-For the next grow, should I plant in 5-gallon pots instead of the 3-gallon pots this time?
Either is suitable. I've used 3 gallon pots instead of 5 for the last few grows and found they perform just as well and meet my needs. Like I said those plants look great... just wait until they swell. IMO the the key to big buds is lots of water. Share some pictures in a few weeks, I'd love to see them again. Cheers.

Thanks Regrowth, I really appreciate that!

I’m not too concerned about saving nutrients as much as I’m concerned about having the best harvest possible. I thought everyone flushed at the end, so this is good to know.

Regarding leaf trimming, this makes total sense, and what I was thinking actually.

I will definitely update with pictures as they progress to harvest!

 

[Fairly Sterile]

Thanks Sueet! I’m just realizing that now. The 3 bottles I’m sure you’re referencing are Grow Big, Tiger Bloom, and Big Bloom. Since all of the helpful tips you all gave me last night, I’ve been reading up on this. The Fox Farm feeding schedule on their site says to use Big Bloom throughout the entire grow, Tiger Bloom once flowering starts, and Grow Big from the start until the 5th week of flowering. So I will definitely be adding Big Bloom now, but I’m wondering how much longer I should add Grow Big, since I’m almost to week 5 of flowering. The other factor is that I’ve been depriving them of Grow Big that they should’ve had for the last 4.5 weeks. Do you think just give them a heavy dose this one last time before I click over to week 5, or even longer?

Also, do you have thoughts on flushing right now? Ok to do? Pointless? Harmful? Do you think the plant roots care about the excess salt buildup?

 

[Fairly Sterile]

Sueet is right Fox Farms requires 3 bottles minimum and IIRC that still doesn’t cover the cal-mag needs.

overall plants look really good, the red shades are nothing to be concerned about but the green appears a bit light… this is the final push in flower and the plant is hungry….

I’m not a fan of flushing but it can be beneficial in certain situations, however you have only used 1 of 3 required nutes. In your case I think flush is the opposite of what you need, they look hungry so why wash nutes down the drain?? However if you do choose to flush then you need to immediately feed as in hit them with a stronger dose of nutrients…right away. They need some N but higher dose of P&K

nope don’t trim fan leaves, not only are they solar panels but those fans are used for transpiration plus storing nutrients, let the plant suck those leaves dry until they fall off naturally

measuring runoff means nothing… if you chase runoff ph you will crash and burn. You only need to be concerned with the ph of liquids going in.

your setting your ph wrong…. you should be at 6.3 going in since you are running in soil. The ph 5.8 range is for coco, hempy and hydro…

In summary… since you are going in with too low PH those nutrients are not available to your plants which is why they are light green and hungry. There are a few one shot does it all nutrients like MC or Geoflora but FF is not a one bottle solution…. you need the other parts of Fox Farms to complete the line up, you can surf for FF feed chart

if that’s concrete slab underneath then I’d get a pallet or two under them for your next run… cold feet can defs be an issue

best of luck- keep us posted

Thanks for your comment 013! I won’t retype the whole thing bc I’m sure this reply thread will start getting really long, but I replied to Sueet above with my concern about Grow Big. I will be adding Big Bloom for the rest of the grow and Grow Big at least once before I’m about to switch to week 5 of flowering. Do you think I should keep adding Grow Big beyond the recommended week 5 (from the FF feeding schedule) since I’ve deprived them of Grow Big for the last 4.5 weeks?

Regarding flushing...if I did flush, I would definitely do a feed immediately after flushing to make sure I got nutes right back in. My only reason for thinking I should flush is the excess of salt in the soil. If you don’t think that bothers the roots though, I will skip flushing.

Good tip, I will leaf the leaves alone!

I’m glad you made the runoff comment because chasing it HAS been driving me crazy. I will up my pH for all remaining waterings. I was only lowering it because my runoff was coming out neutral and I thought I needed it to be more acidic. But, as you said, I will stop paying so much attention to runoff.

It is not concrete, but thanks for the tip. It’s an OSB plywood floor lined with vinyl flooring, sitting on top of a carpeted basement, so they are not getting cold at all.

 

[Fairly Sterile]

wanted to add….

you’ve done an amazing job here- seriously your plants look top notch, plus you did one heck of a thorough write up above.

over time you will gain experience and confidence. at first it seems sketchy but most of us add nutes very frequently in flower. So right now you are doing feed, water and that’s as it should be, but later on you can bump to feed, feed, feed, water for your next grow cycle if you feel comfortable.

also you can modify the wet dry cycle so you are feeding or watering more frequently in flower cycle. the wet / dry is mostly intended to build roots in veg…

welcome aboard Fairly Sterile!

Thanks again! I really appreciate the feedback. Not all forums are so nice, patient, and helpful to newbies, as you all have been with me, so I super appreciate it!

 

[013]

I’d try to follow the FF feed charts, I’ve ran a few FF grows but defs not an expert

yep chasing runoff means tinkering with your input numbers to get a different number in your runoff… and typically those who follow that procedure ride it right into the ditch, but it’s all good we’ve got your back.

you’ve got four ginormous lovely ladies and are almost to the finish line so kudos on that!

I would suggest staying right here posting your updates on the FAQ page and next time around start a grow journal with us. Think it’s killer that you are so well prepared,

peace out my friend!

 

[Fairly Sterile]

I’d try to follow the FF feed charts, I’ve ran a few FF grows but defs not an expert

yep chasing runoff means tinkering with your input numbers to get a different number in your runoff… and typically those who follow that procedure ride it right into the ditch, but it’s all good we’ve got your back.

you’ve got four ginormous lovely ladies and are almost to the finish line so kudos on that!

I would suggest staying right here posting your updates on the FAQ page and next time around start a grow journal with us. Think it’s killer that you are so well prepared,

peace out my friend!

Thank you! I will definitely keep posting updates!

 

[bluter]

fox farm has a two-part and a three-part bottle nute system. all of the parts are used at each feeding in differing amounts depending on plant size and development. i'm not sure if you are using the correct system or using the nutes correctly.

the pots look too small for the amount of plant they are supporting. 5 gallon would have kept them happy. they are eating themselves in an effort to complete flower. the 3 gallon isn't holding enough and they are very likely root bound. an earlier flip would have been a bit better in that size.

 

[Fairly Sterile]

fox farm has a two-part and a three-part bottle nute system. all of the parts are used at each feeding in differing amounts depending on plant size and development. i'm not sure if you are using the correct system or using the nutes correctly.

the pots look too small for the amount of plant they are supporting. 5 gallon would have kept them happy. they are eating themselves in an effort to complete flower. the 3 gallon isn't holding enough and they are very likely root bound. an earlier flip would have been a bit better in that size.

Thank you bluter!

I was concerned that pots were too small, so I appreciate your comment. I will switch to 5 gallon pots for the next grow.

 

[Sueet]

Thanks Sueet! I’m just realizing that now. The 3 bottles I’m sure you’re referencing are Grow Big, Tiger Bloom, and Big Bloom. Since all of the helpful tips you all gave me last night, I’ve been reading up on this. The Fox Farm feeding schedule on their site says to use Big Bloom throughout the entire grow, Tiger Bloom once flowering starts, and Grow Big from the start until the 5th week of flowering. So I will definitely be adding Big Bloom now, but I’m wondering how much longer I should add Grow Big, since I’m almost to week 5 of flowering. The other factor is that I’ve been depriving them of Grow Big that they should’ve had for the last 4.5 weeks. Do you think just give them a heavy dose this one last time before I click over to week 5, or even longer?

Also, do you have thoughts on flushing right now? Ok to do? Pointless? Harmful? Do you think the plant roots care about the excess salt buildup?

Re: thoughts on flushing, it is one of the things on the fox farm's schedule, so I recommend following their recommendation

I would probably go ahead and give at least a couple of doses with the Grow Big so the plant can catch up to some degree. Maybe taper it off or lessen it steadily rather than just cutting it off to make up for the deprivation. Or, write Fox Farms an email and ask what they would recommend, since they've almost certainly seen it before.

 

[SmokingWings]

Long time toker, first time grower. My state just legalized home growing in August 2023, so I took full advantage! Unfortunately, I’m a newbie, so I am having some issues and could really use some expert opinions on what is going on.

Fantastic looking plants and the amount of buds is just great. A good job.

.... opinions on what is going on.

What is shown in the photos is a very common thing that comes up here. The loss of green color from the leaves and the increase in yellows, reds and purples usually starts in the 2nd to 3rd week of flowering continues to the end. My thoughts on what is happening is that you did such a good job during the growing stage that the plants went into the flowering stage at "full speed ahead" mode and developed all those stacks of bud sites. So, the plants are now demanding more than the root system can get from the soil and the basic fertilizing you are doing.

Kinda late to bring the plant back around to the healthy green leaves it had about 4 to 5 weeks ago but you can try to slow down and maybe even stop the loss of color.

The Fox Farm feeding schedule on their site says to use Big Bloom throughout the entire grow, Tiger Bloom once flowering starts, and Grow Big from the start until the 5th week of flowering.

The way I see it the Big Bloom is not a fertilizer but is the most important of the 3 as far as a soil grow is concerned. The amounts of N-P-K are minimal; what makes it important is that it contributes so much to the level of microbes and mircro-organisms in the soil.

Or should I just let them ride it out at this point and only flush at the end, right before harvest?

Based on the schedule it looks like they recommend a flush being done about a week or so ago and then another one at two weeks before harvest and not just before. That helps to reset the soil by getting rid of any excess salt build-up and still allows enough time for the final finishing of the buds.

would probably go ahead and give at least a couple of doses with the Grow Big so the plant can catch up to some degree. Maybe taper it off or lessen it steadily rather than just cutting it off to make up for the deprivation. Or, write Fox Farms an email and ask what they would recommend, since they've almost certainly seen it before.

Yes, this from Sueet is something to consider doing in the next day or two. Up to you if you are an experimenter and want to see what happens with a couple doses of the Grow Big. Or skip the experimenting and call or email Fox Farm and bring up what is happening.

They will tell you what to do about emailing any photos. Me, I have always called them and we end up having a some interesting conversations and I often end up with more tips than I can remember.

 

[SmokingWings]

I was concerned that pots were too small, so I appreciate your comment. I will switch to 5 gallon pots for the next grow.

A lot of growers go with pots in the 3 or 5 gallon range. There is one thing I keep in the back of my mind. If the switch is made from 3 to 5 gallon pots then the plants are often a bit bigger to match the extra soil when flowering starts so the same problem seems to come back. Something to keep in mind so that you are ready.

Sometimes that extra size ends up over growing the available room. And it looks like you are pretty close to being there already with the 3 gallon pots. But, that is a sign that you have done a good job with these plants.

 

[Fairly Sterile]

Re: thoughts on flushing, it is one of the things on the fox farm's schedule, so I recommend following their recommendation

I would probably go ahead and give at least a couple of doses with the Grow Big so the plant can catch up to some degree. Maybe taper it off or lessen it steadily rather than just cutting it off to make up for the deprivation. Or, write Fox Farms an email and ask what they would recommend, since they've almost certainly seen it before.

Thanks again, Sueet!

 

[Fairly Sterile]

Fantastic looking plants and the amount of buds is just great. A good job.


What is shown in the photos is a very common thing that comes up here. The loss of green color from the leaves and the increase in yellows, reds and purples usually starts in the 2nd to 3rd week of flowering continues to the end. My thoughts on what is happening is that you did such a good job during the growing stage that the plants went into the flowering stage at "full speed ahead" mode and developed all those stacks of bud sites. So, the plants are now demanding more than the root system can get from the soil and the basic fertilizing you are doing.

Kinda late to bring the plant back around to the healthy green leaves it had about 4 to 5 weeks ago but you can try to slow down and maybe even stop the loss of color.


The way I see it the Big Bloom is not a fertilizer but is the most important of the 3 as far as a soil grow is concerned. The amounts of N-P-K are minimal; what makes it important is that it contributes so much to the level of microbes and mircro-organisms in the soil.


Based on the schedule it looks like they recommend a flush being done about a week or so ago and then another one at two weeks before harvest and not just before. That helps to reset the soil by getting rid of any excess salt build-up and still allows enough time for the final finishing of the buds.


Yes, this from Sueet is something to consider doing in the next day or two. Up to you if you are an experimenter and want to see what happens with a couple doses of the Grow Big. Or skip the experimenting and call or email Fox Farm and bring up what is happening.

They will tell you what to do about emailing any photos. Me, I have always called them and we end up having a some interesting conversations and I often end up with more tips than I can remember.

Thank you for all the info, this is really helpful! My biggest mistake was not following the FF feeding schedule through the majority of the grow. Honestly, this newbie didn't even know it existed until you all mentioned it. I will be following it much closer next grow!