ChiefRunningPhist
Well-Known Member
Sounds like a pretty nice setup to me
horticultural veg light build, lost...stumped... I need advice, come on in!
- Thread starter oldbeancounter
- Start date
Need some advice, I'm running HLG 600 4000K VEG, a 3000k in Flower both at full power. Is this beneficial or detrimental?
Cheers
Randomblame
Well-Known Member
Beneficial! 3k has proven many times to yield the best and with 4k in veg you get a nice and compact base and lots of strong twigs. You could also mix it in the flowering stage.. Could help to keep stretchy strains under control.
There is nothing wrong with such a combo!
Prawn Connery
Well-Known Member
I'm just going to come right out and say it: blue light bombardment in veg is a canna myth perpetuated by old-school growers who tried to veg under HPS - which has almost no blue light compared to MH - and were left with lots of stretch due to the imbalance of blue vs red/far red.
LED light - even 3000K - has a lot of blue in it already.
All those yield studies you've read online (or not) - you know the ones "Which spectrum yields best" etc - come to the same conclusion: 10-15% blue with predominantly red and some green yields best for a wide range of plant species.
The kicker is nearly all these studies are conducted using leafy greens and herbs during VEG - not flower or fruiting. Blue inhibits shade response - which keeps plants compact - but high amounts of blue diminish leaf mass. Red promotes leaf mass.
I went from building 5000K strips to 4000K strips for veg and noticed the results straight away. I then started vegging under 3000K and the results - apart from a small amount of stretch - were equal or better than 4000K.
As @Rocket Soul mentioned, it can be strain dependent - in my experience indicas tend to do better under bluer light than sativas. But overall, if you want the fastest growth in flower and veg, you need no more than 15% blue.
There are so many scientific studies proving this, I'm not sure why many still think 5000K is better than 3000-4000K for veg
See "Myth 3": https://thegreensunshineco.com/7-myths-led-grow-light-companies-tell-you/
TLDR, see photos: https://www.semanticscholar.org/paper/Leaf-photosynthetic-rate,-growth,-and-morphology-of-Kang-Park/39d9e0bb0c53aca87c8df47aed04ebbcb8fad83d
Same: https://www.frontiersin.org/articles/10.3389/fpls.2015.00019/full
Etc
LED light - even 3000K - has a lot of blue in it already.
All those yield studies you've read online (or not) - you know the ones "Which spectrum yields best" etc - come to the same conclusion: 10-15% blue with predominantly red and some green yields best for a wide range of plant species.
The kicker is nearly all these studies are conducted using leafy greens and herbs during VEG - not flower or fruiting. Blue inhibits shade response - which keeps plants compact - but high amounts of blue diminish leaf mass. Red promotes leaf mass.
I went from building 5000K strips to 4000K strips for veg and noticed the results straight away. I then started vegging under 3000K and the results - apart from a small amount of stretch - were equal or better than 4000K.
As @Rocket Soul mentioned, it can be strain dependent - in my experience indicas tend to do better under bluer light than sativas. But overall, if you want the fastest growth in flower and veg, you need no more than 15% blue.
There are so many scientific studies proving this, I'm not sure why many still think 5000K is better than 3000-4000K for veg
See "Myth 3": https://thegreensunshineco.com/7-myths-led-grow-light-companies-tell-you/
TLDR, see photos: https://www.semanticscholar.org/paper/Leaf-photosynthetic-rate,-growth,-and-morphology-of-Kang-Park/39d9e0bb0c53aca87c8df47aed04ebbcb8fad83d
Same: https://www.frontiersin.org/articles/10.3389/fpls.2015.00019/full
Etc
Prawn Connery
Well-Known Member
IMO, it's fine. You could add 620-660nm supplements in flower if you really wanted to.
EDIT: @Randomblame beat me to it!
What I've noticed since I switched from CMH to Led is that the veg seems to be slower in height but bushy, some strains seems to curl at new growth sites. And when I move the plants into flower they explode in height and width. I'm leaning towards purchasing another hlg600 3000k for veg, unless you guys think I can dial back on the potentiometer/power to promote better growth.
Cheers !
Prawn Connery
Well-Known Member
Do you use a magnesium supplement? Magnesium is reliant on transpiration, which can slow under LED due to the lack of heat compared to HIDs. Mg helps with the uptake of phosphorous, which can lead to "little leaf" syndrome where growth stunts and new leaves are thin and start to curl in on themselves. This is often associated with purpling stems.
Do you change nutrients when you go into flower? Ie; do you use separate veg nutes and flowering nutes and do you increase the feeding schedule when you switch to flower? Do you monitor your pH in and out?
Do you change nutrients when you go into flower? Ie; do you use separate veg nutes and flowering nutes and do you increase the feeding schedule when you switch to flower? Do you monitor your pH in and out?
Yes I monitor ph (soil) Michigan M3 Mix, I have measured ppm in/out. I switched from well water to RO and back to well (plants seemto respond better). I use Sweet Stash/worm castings (tea) for both veg/flower. I use Great White on my roots when I transfer to lager pots. I apply Myco Chum and Blossom Builder in my tea for Flowering. I did add cal mag and Witches Water to a couple of plants that showed a deficiency but I think that they are sensitive to the Led lighting, additives didn't seem to improve them. I usually brew for 24hr before applying. The strains that seem to be adversely affected by the LEDs are Chem Dog 4 and Blueberry Kush. The Strawberry Cough is resiliant.
Prawn Connery
Well-Known Member
Is that the "leaf curling" you are talking about? Because that's a picture of a plant that was starting to flower but is being forced back into veg. It can happen when you take clones from plants that are starting to flower and then trying to grow them on.
I didn't realise you were growing in soil, but soil is a good buffer, so it's usually rare to have pH problems if you have a well-balanced mix to begin with. Worm castings (and their teas) are also good sources of magnesium, calcium and other trace elements, as well as NPK, so I wouldn't expect a deficiency if you are regularly feeding.
I'm not sure what's going on with that yellow plant in the middle of the bottom photo, but it looks like it is seriously underfed or you might have a case of root rot - which is the only thing I can think of that would explain a plant suddenly going downhill like that, unless you are excessively flushing it.
The most common problems with soil are usually to do with overwatering and overfeeding. Blueberry strains can be notoriously finicky to grow, but they are usually sensitive to nutrient burn, not deficiency. They don't like a lot of nitrogen. But the yellow plant in the photo is clearly nitrogen deficient - I would say alround deficient.
The other plants look good, so you must be doing something right! Can you think of anything you are doing differently to the affected plant you're not doing to the others?
One piece of information you provided is you used RO water and the plants didn't like it as much as well water. RO water has no nutrient, but well water can have high levels of calcium and magnesium carbonates - which would point to a Cal-Mag deficiency. Or, possibly your soil is too acidic, as "hard" water tends to be alkaline.
There's not much else I can think of at this point.
I didn't realise you were growing in soil, but soil is a good buffer, so it's usually rare to have pH problems if you have a well-balanced mix to begin with. Worm castings (and their teas) are also good sources of magnesium, calcium and other trace elements, as well as NPK, so I wouldn't expect a deficiency if you are regularly feeding.
I'm not sure what's going on with that yellow plant in the middle of the bottom photo, but it looks like it is seriously underfed or you might have a case of root rot - which is the only thing I can think of that would explain a plant suddenly going downhill like that, unless you are excessively flushing it.
The most common problems with soil are usually to do with overwatering and overfeeding. Blueberry strains can be notoriously finicky to grow, but they are usually sensitive to nutrient burn, not deficiency. They don't like a lot of nitrogen. But the yellow plant in the photo is clearly nitrogen deficient - I would say alround deficient.
The other plants look good, so you must be doing something right! Can you think of anything you are doing differently to the affected plant you're not doing to the others?
One piece of information you provided is you used RO water and the plants didn't like it as much as well water. RO water has no nutrient, but well water can have high levels of calcium and magnesium carbonates - which would point to a Cal-Mag deficiency. Or, possibly your soil is too acidic, as "hard" water tends to be alkaline.
There's not much else I can think of at this point.
Randomblame
Well-Known Member
What temps and humidity range do you use?
LED has not heat radiation like HPS/CMH and the leaf temps under LED light are ~3°C cooler. When you need 25°C ambient temps under CMH to get leaf temps of 28°C you need to increase ambient temps to 28-30°C to get the same leaf temps like with LED's. As soon as you increase ambient temps in veg the plants will start to grow faster.
BUT...
Keep an eye on your humidity! Higher ambient temps make it neccessary to increase RH too. With HPS and 25°C 45-55% are sufficient in the late flowering stage. With LED and 28-30°C you need 60-65% at least in the flowering stage and in veg you need an even higher humidity!
The reason is called VPD what means vaper pressure difference and it means the pressure difference between ambient and the vapor pressure inside the leaves. The lower the humidity the higher the pressure to evaporate water. Plants take up more water and nutes with a too low humidity and in the worst case you get issues with too much calcium uptake which in turn blocks other metalls like Mg, P and Iron for instance. To avoid such issues you need to keep temps and humidity always in balance.
With HPS this was not needed. HPS/CMH light has almost the same amount of heat radiation like the sun. The leaves are warmer like ambient temps they can regulate the transpiration themself much better. With LED and its cold light it's neccessary to do this for your plants and keep the humidity always in a good range.
This below is a chart you can use for all 3 plant stages. It is calculated with -1° leaf temps and in the upper right corner you see the recommended VPD's for germination, veg and flowering stage.
The cyan range is for germination and early veg, the green area is for veg and early flowering stage and the yellow area is for the 2nd half of the flowering stage.
To figure out the VPD in your grow room look at first on the left side and look at the temperatures. Then slide to the left untill you have the field with the according humidity. The values you see at the intersection/meeting point is the current VPD in your groom. If you keep the humidity in a healthy range and your plants feel happy you'll also need less calmag.
The good thing with LED's is you need no AC and can use a much smaller exaust fan but you should invest in a small humidifier. As you see above the humitidy is one of the most important factors for success with LED's. Keep the VPD in a healthy range and you plants feel good and will do much better.
There are other ways to deal with a too high VPD like lowering the nutrient strength accordingly. But its only possible with a hydro system. In soil you have not enough control over the nutrient uptake because its much more difficult to reduce the nutrient level lets say by 20% because of a 20% too high VPD. With a hydro system you can easily reduce it.
There are temp/humidity controllers available where you can set a certain VPD too but IMO you don't need them. Simply set the temp and humidity range you want, add the exaust fan to the temp side and the humidifier to humidity side of the controller and the controller will keep the VPD where you want him.
If you follow the rules above you'll see much faster growth in veg and it will be much easier to keep your plants healthy.
I would also recommend to further use 4k for the vegetative stage. Without a strong and bushy base the plants would stretch out much more and the lower twigs can not keep up with the main stem. You would simply need more LST work to get an even canopy. Better increase ambient temps and humidity to 28°C/65-70% and you'll see your plants growing as fast or faster like under CMH/MH.
Randomblame
Well-Known Member
The girl in the 1st pic. clearly shows reveg symtomes like PC has mentioned already and the yellow girl in the center of the last picture got too much light with too low ambient temps and a too low humidity.
It looks like bleaching combined with locked out nutrients!
I've seen that many times before I've learned how important a proper VPD is. Expecially in a big tent not filled completely the plants can not transpire as much as needed to reach a good humidity. You need a small humidifier to keep the level the plants need.
Germination/early veg = 75-80% RH or 0,4-0,8kpa
Veg and early bloom = 70-75% and or 0,8-1,2kpa
from end of the stretch = 60-65% RH or 1,2-1,6kpa
Temp range 28-30°C
The higher the VPD the higher the nutrient uptake. You can regulate transpiration and nutrient uptake with the nelp of the VPD.
At night you can reduce the humidity without getting issues and especially in the last few weeks you should try to keep it ~50% at night.
For now I would add a few bowls of water and direct a fan on the water surface to evaporate more water. You can also hang up a few wet towels until you have the humidifier. And dimm down the exaust fan as much as possible it helps to get higher ambient temps and humidity.
I can increase my humidity by just keeping the windows of my lung room closed but you are forced to add CO² without fresh air.
Prawn Connery
Well-Known Member
Hey mate, there might be some bleaching at the top, but that whole plant is sick, all the way down to the lower growth. And it looks like an overall deficiency, not just Cal-Mg or N.
Interestingly, that plant looks like it was the best performer in that group until it was affected, so I'm going to go out on a limb and say it needs a good dose of alround NPK fertiliser, as it looks to me like it's starving. I'm not sure if, perhaps, @Bourbon 2 has been overwatering and possibly flushing out a lot of nutrient, as that's kind of what it looks like to me.
I can only make an educated guess until we have more details.
Interestingly, that plant looks like it was the best performer in that group until it was affected, so I'm going to go out on a limb and say it needs a good dose of alround NPK fertiliser, as it looks to me like it's starving. I'm not sure if, perhaps, @Bourbon 2 has been overwatering and possibly flushing out a lot of nutrient, as that's kind of what it looks like to me.
I can only make an educated guess until we have more details.
Randomblame
Well-Known Member
Hmm! I think the plant in the center is at least 4 weeks older as the other plants. It only looks like bleaching but I think she stand a few weeks alone under these light or at least with a permanent to low humidity. If the VPD is too high for a long time calcium locks out much more nutes than only magnesium. Mg is only the 1st one affected because calcium is its direct anagonist but if you keep the VPD around 1,8kpa for lets say 3 weeks the whole nutrient system is affected.
I've seen exactly this symtomes with yellow leaf margins and only a little green left on the veins.
The plant on the left side also shows a slightly discoloration already and I bet the current humidity is in the lower 50% range or even lower.
Compost teas have all what's needed but the concentration is not very high. But he has also used a pre fertilized soil mix and I don't think there are not enough nutes. With soil there is not much you can do when the VPD is too high. With cocoDTW we need just to lower the ppm's accordingly and its much easier to deal with a too low humidity.
It is really a common issues for LED noobs coming from HPS and organic soil. For this reason I've changed my growstyle to coco too. I can keep the humidity high enough to also keep plants in soil happy but with 80% humidity inside the lung room there is a high risk to get mold. With a hydro system its much easier and many hydro growers have much less problems because they intuitively adjust the nute strength when they see issues. In soil you only have control over what you add later but to lower the nutrient strength in the soil you would need to flush it. And in organic soil it has probably not much of an effect anyways..
Let's see what he says..
I still bet his humidity was and still is at least 10-20% too low. And the surrounding plants are either a few weeks younger or its a different strain.(or both) I can not see what the thermometer says(upper right corner) but it should hang between the tops of the plant and not at the same height with the light and mounted on the walls. It displays not the conditions he has around his plants.
A proper VPD has solved virtually all my problems with LED's and since then it's always the first thing I adjust to avoid issues. If you now for sure the VPD is okay and you get issues its as easy to fix them like under HPS. But if you don't know what the VPD is it can drive you crazy cuz you can not solve your issues no matter what you do and this goes especially when using soil.
Try it out and use the chart above to keep the humidity in a good range. Even if you have less issues with your growstyle you'll see happier plants when the VPD is in a healthy range.
Hey guys, thanks for all your feedback
I'm still at work but I'll dig in to your comments after. But just a quick response, the one plant in veg that has new site curling is a clone. I had 4 of them and they all did the same. Light schedule, feeding, temps and humidity all remained the same throughout.
The Blueberry Kush that shows distress is much the same. Temps @ 72-74, RH @ 70% (pushing higher than I'd like). Feeding and watering same schedule as the other plants. I often check my ph levels in soil with soil pen and it varies from 6.8 to 7.5. This specific one began showing signs of stress 4 wks into flower, currently 8.5 wks in. I'm thinking that the led lighting has some effect on it, idk. But at least the bud sites look good, btw I haven't had any issues of ever over watering/root rot with them being in air pots. However I'll look at the root ball when I harvest, the tryclomes are still clear. Cheers !
I'm still at work but I'll dig in to your comments after. But just a quick response, the one plant in veg that has new site curling is a clone. I had 4 of them and they all did the same. Light schedule, feeding, temps and humidity all remained the same throughout.
The Blueberry Kush that shows distress is much the same. Temps @ 72-74, RH @ 70% (pushing higher than I'd like). Feeding and watering same schedule as the other plants. I often check my ph levels in soil with soil pen and it varies from 6.8 to 7.5. This specific one began showing signs of stress 4 wks into flower, currently 8.5 wks in. I'm thinking that the led lighting has some effect on it, idk. But at least the bud sites look good, btw I haven't had any issues of ever over watering/root rot with them being in air pots. However I'll look at the root ball when I harvest, the tryclomes are still clear. Cheers !
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Prawn Connery
Well-Known Member
OK, those clones obviously aren't autos, but that is 100% photoperiod induced curling when the plant transitions from a flowering cycle (12/12) to a veg cycle. Like I said, it can happen when you clone from a plant that has already started to flower. You can tell because the fan leaves go from 3 blades to 1 blade with pistil formation before they eventually return to normal growth (3 blades, 5 blades, 7 blades etc).
That pH is not especially high for soil.
However, I just googled your M3 mix and discovered it is a soilless mix - not soil. That means peatmoss, which retains water more than soil, and needs a pH of around 6.5 or less according to the manufacturer: https://www.m3michiganmademix.com/about-m3/
They also instruct not to use additives, as the soilless mix already contains the correct amount of fast and slow-release fertilisers from veg to flower. For heavy feeders, they say to top-dress with more M3.
So I'm wondering, what sized pots are you using and is there a possibility the plant is root-bound? That can sometimes lead to a deficiency or lock-out as salts can build up faster in the root zone - especially if you have been using additives.
None of this takes away from what @Randomblame is saying, I'm just looking for other clues.
That pH is not especially high for soil.
However, I just googled your M3 mix and discovered it is a soilless mix - not soil. That means peatmoss, which retains water more than soil, and needs a pH of around 6.5 or less according to the manufacturer: https://www.m3michiganmademix.com/about-m3/
They also instruct not to use additives, as the soilless mix already contains the correct amount of fast and slow-release fertilisers from veg to flower. For heavy feeders, they say to top-dress with more M3.
So I'm wondering, what sized pots are you using and is there a possibility the plant is root-bound? That can sometimes lead to a deficiency or lock-out as salts can build up faster in the root zone - especially if you have been using additives.
None of this takes away from what @Randomblame is saying, I'm just looking for other clues.
Hey guys thanks again for your help. I'll try to answer a few things. The M3 mix is hot, I wanted to go strictly organic without adding nutrients other than the Sweet Stash and adjust ph. So when the two plants yellowed (Blueberry Kush, Chem Dog #4) I was freaking out thinking defiencency but my other plants (Strawberry Cough) seemed fine. I added cal mag and if it helped I couldn't see any change/improvement.
The two in the back right corner are in 7gal air pots. The one yellowed is 8wks in flower, the tryclomes are still clear, the one on the right rear is a clone from it and is 4wks in flower.
All others are in 5gal std pots. I add 1.5 gal to air pots and 1 gal to 5gal pots during tea feeding or watering. I was told that the company who makes the m3 started farming out to meet their demands and the mix isn't as good, so perhaps I got a bad bag/lot number. During winter I used a humidifier but darn near need a dehumidifier now, lol. One thing to note is that the plant that's curling has always been on 18/6 schedule since cloned. Tryclomes are at all the curl/growth sites, so yeah it's as if I pulled it from an adult pla
nt in flower but I didn't, I'm stumped. I'll leave it in the veg tent just to see if it rebounds. The humidity meter I had in the flower tent was clearly off so I installed a different one, seems to be at 60RH. I've always tried following the VFD, seems easier in the winter. I'll take photos of the roots and upload when I harvest, (harvesting, I'm still learning)...drying, curing oh and patience
The two in the back right corner are in 7gal air pots. The one yellowed is 8wks in flower, the tryclomes are still clear, the one on the right rear is a clone from it and is 4wks in flower.
All others are in 5gal std pots. I add 1.5 gal to air pots and 1 gal to 5gal pots during tea feeding or watering. I was told that the company who makes the m3 started farming out to meet their demands and the mix isn't as good, so perhaps I got a bad bag/lot number. During winter I used a humidifier but darn near need a dehumidifier now, lol. One thing to note is that the plant that's curling has always been on 18/6 schedule since cloned. Tryclomes are at all the curl/growth sites, so yeah it's as if I pulled it from an adult pla
nt in flower but I didn't, I'm stumped. I'll leave it in the veg tent just to see if it rebounds. The humidity meter I had in the flower tent was clearly off so I installed a different one, seems to be at 60RH. I've always tried following the VFD, seems easier in the winter. I'll take photos of the roots and upload when I harvest, (harvesting, I'm still learning)...drying, curing oh and patience
Randomblame
Well-Known Member
Hmm! Humidity seems okay but temps are a little low IMO!
Are the temps always that low or even lower? Temps have a high effect on plant metabolism.
A too high PH is also problematic and can for instance reduce the availability of iron, manganese, boron or copper.
Has one of the additives you have used a higher PH value? Did you check the PH of the nute soup?
When I've used organic soil I've only used molasses and kelp extract to feed them and the PH of the nute soup was always around 8 and I had to add a few drops citric(veg) or phosphor acid(bloom) to bring it down to just below 7.
Plants can adjust the PH themself within a certain range but if you feed them constantly with a too high PH the soil PH shifts too and some elements become more and more available and that's the main reason some of the micro elements gets locked out. (See 2nd pic.)
Each element has its own antagonist and excess of one element always cause a lockout of one or more other elements.
Ambient or better leaf temps also have a high effect on plant metabolism. A plant getting 500μMol/s/m² @30°C can do better like the same plant under 1500μMol/s/m² but only 20°C.
With 20°C/60% RH the VPD would be only ~0,8kpa which would be okay for the early vegetative stage but plants in the flowering stage can not drink enough to assimilate enough nutes with such a low VPD. You can only compensate that with a higher soil EC or when you lower the humidity to ~30-40% when you keep that temp level.
In the flowering stage you want the VPD between 1,2 and 1,6kpa.
For now I see two things you can do..
1. Bring the temps up to at least 25, better 28°C but keep the current humidity level.
You could dimm the exaust fan or stop it time wise and reduce hanging height of the lamp to 12-16".
2. Bring the soil PH down to right below 7. I would flush the younger ones with PH6,5 as soon as they are dry and feed with
trace minerals which are locked out currently(with kelp extract for instance).
Especially when you grow in organic soil it's even more important to keep the VPD in a good range according to the plant stage. You simply have not enough control over what and how much nutes getting absorbed. A too low VPD means the plants get not enough nutes and a too high VPD means they absorb too much. The VPD is like a balancer and keeps transpiration and nutrient uptake within a healthy range. It's a lot of stress for the plants to deal with a too high or low VPD and it always slows down growth. With a too low VPD you need a higher EC to compensate it and with a too high VPD you need to reduce the EC to keep the plants happy. But that's almost impossible when you grow organic style.
Prawn Connery
Well-Known Member
It just so happens I have a plant outside that had started to flower before I brought it inside and put it under 18/6 to regenerate, before putting it back outside again (no room to flower indoors). You can clearly see the curled leaves and how, eventually, the plant regenerates with normal growth. The plants always go through this "mutant" period first where the shoots and leaves curl up and do funny things - half leaves, half pistils - before vegetative growth stabilises again. So I am 100% sure your clones have gone through some sort of photoperiod change to induce flowering before trying to regenerate. At a guess, it could be a timer issue, or there could be ruderalis genes in that strain, or there could have been another stress event (added hormones?) that triggered the clones to flower and then regnerate under 18/6. Stranger things have been known to happen . . . But it has nothing to do with LED light.
So looking at the yellow plant, a potassium deficiency appears to be the main culprit, as well as magnesium. High levels of calcium (indicated by high pH) can interfere with K and Mg uptake, and micronutrient uptake is also affected by high pH.
Incidentally, a high VPD - as @Randomblame pointed out - can also cause high levels of Ca to lock out other nutrients. But I suspect you may have had a hot-shot of lime in that mix, or you may have added too much Cal-Mag. Again, it's just a guess, but flowering plants need a lot of K and to a lesser extent Mg, and you can see where your plant has been taking these reserves from the fan leaves. Burnt, curled-up tips and margins are a sign of K deficiency, and interveinal chlorosis is a sign of Mg deficiency.
My own plants will start to go like that if I let pH drift too high in coco, so the first thing I'd try to do (although it is a bit late for that pant now) is try to get your pH down to 6-6.5, and then use a mild alround fertiliser. That Sweet Stash looks like it might do the job, as its got fulvic and humic acids which will help lower pH, a high Mg:Ca ratio, a little bit of nitrogen and potash (K) and is organic based, so shouldn't burn your plants in the correct dose. Hope some of this helps.
So looking at the yellow plant, a potassium deficiency appears to be the main culprit, as well as magnesium. High levels of calcium (indicated by high pH) can interfere with K and Mg uptake, and micronutrient uptake is also affected by high pH.
Incidentally, a high VPD - as @Randomblame pointed out - can also cause high levels of Ca to lock out other nutrients. But I suspect you may have had a hot-shot of lime in that mix, or you may have added too much Cal-Mag. Again, it's just a guess, but flowering plants need a lot of K and to a lesser extent Mg, and you can see where your plant has been taking these reserves from the fan leaves. Burnt, curled-up tips and margins are a sign of K deficiency, and interveinal chlorosis is a sign of Mg deficiency.
My own plants will start to go like that if I let pH drift too high in coco, so the first thing I'd try to do (although it is a bit late for that pant now) is try to get your pH down to 6-6.5, and then use a mild alround fertiliser. That Sweet Stash looks like it might do the job, as its got fulvic and humic acids which will help lower pH, a high Mg:Ca ratio, a little bit of nitrogen and potash (K) and is organic based, so shouldn't burn your plants in the correct dose. Hope some of this helps.
Prawn Connery
Well-Known Member
Geeze, we're bombarding him with info, aren't we? No-one can say we're not thorough!
