Nitrogen/magnesium/calcium deficiency and what im planning to do

Nugnewbie

Well-Known Member
If someone could chime in with some knowledge. These plants are in coots mix. Two plants in each SIP. 20% compost, 40% perlite, pumice, and rice hulls. 40% peat moss. Plants transplanted from 1 gal pots to City Picker SIPs on March 2nd. Started noticing deficiency (nitrogen on some, magnesium as well, but mainly on the Gorilla zkittlez) around March 21 and top-dressed with ewc and watered in with fish hydrolysate. Have done a few foliar feeds with Epsom salts, sometimes including TM-7. On March 26 I top dressed with more coots mix medium. The one pic shows a Gorilla zkittlez from Barney's Farm that the leaves curled, and showed what I thought was magnesium deficiency, thus the foliar feeds. I had the ppfd up fairly high (around 700 ppfd), so I've backed the light off a bit. Temps have been between 82-84°F lights on, 76-78°F lights out. Humidity has been fairly high, close to 70%rh lights on, 65%rh lights out. Have lots of air movement (maybe too much) and good extraction with 4" intake, and 6" exhaust with ACI inline extractor fans. No carbon filter yet. I have ordered some calcium nitrate and was going to use it in a foliar feed hoping to balance out the calcim/magnesium as it appears on some leaves, that along with nitrogen deficiency, a calcium deficiency is appearing. Was hoping to get some confirmation on what I'm seeing, and some advice on the use of calcium nitrate in a foliar feed, as in concentration to use. Any help is appreciated.

 

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Yeah you've got a nitrogen deficiency and some heat stress going on. Funnily enough I am dealing with the same problem at the minute but mine is not as bad as yours
 
In the last picture you've got darker green leaves lower down than the lighter ones above.
I don't think N works that way, it's normally robbed from lowest leaves to feed the higher leaves and works it's way up.

You've also got leaves pointing up on which they are yellow and striped on the tips.

Red veins, red stems.
Bigger fan leaves looking worse.

All points to slow light burn.

What's your light schedule?
You said your ppfd but not hours of light

I could be wrong about the cause, but it's something to consider before you start chasing your tail.
 
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I'm running the lights on 18 on, 6 hrs off. Yes, you are probably right about the light burn so I will reduce the light again a bit more. I suppose these leaves that are damaged by the excess light and N deficiency won't recover, but do you think calcium nitrate might give a good N boost to help address the problem? Thank you for responding.
 
Ok, going forward I will reduce the light some more.
Don't reduce your light anymore than 18 on and 6 hours off because they will probably start flowering. unless you want them to flower?
No, will just reduce ppfd, and therefore also DLI, to reduce excess light. I want to flip, but want plants in better shape beforehand. They are getting bigger, so I need to flip soon.
 
idk if u can save that upper growth tbh. They’re not up taking anything for some reason. Look at them dark stems and pale foliage. IMO they’re on their way out unless u correct it soon.
As stated above the lower growth does look better. So if u need or want to try and salvage them here’s what I would try.

1) I’d turn my light down significantly like to 20% and 30” above the canopy and use Gas Lantern Technique lighting schedule.

2) Get some castings and bagged soil (FFOF or Build a soil blend) and heavily top dress.

3) Top them and remove dead/dying growth if the lower growth looks healthy.

4) Lightly top water for a couple weeks.

5) Keep the RH around 60-65 but lower my temp to 78.

Again this is what I would do. I’m in City Pickers rn myself using GLR lighting. If I had to bet I’d say your medium didn’t have time to cultivate enough benes and without knowing the state of the plants at transplant (if root bound or unhealthy) they may not have taken as the soil wasnt healthy enough to sustain what the plant needed from it. I say reduce the light bc how can it possibly need high intensity when they’re struggling. As said above you may be giving them too much light and they’re not equipped to handle it bc your medium and root system isn’t established. I hope any of the above info is useful. I’d prolly just start over tho.
 
I have had similar problems on previous grows, but haven't learned how not to create these issues. Thank you LewberDewber for weighing in. I've seen pictures of your grows and tbh they look awesome, so I respect your opinion on this. Plus, you grow in the same planters, so there's that.

I am going to try to save them. Maybe a bad idea, but running out of supply, and not growing during the hotter months is why I want to work at rescue. Also, i appreciate your honest take, as hearing you'd likely just start over is definitely not what i want to hear, but is an experienced growers assessment which is what I was hoping for. Not that anyone else who chimed in isn't appreciated, but I think your best suited to give your opinion because you use similar methods, but have very nice results.

As far as your advice for moving forward, I'll go through your advice with my further questions now that I have your attention.

1) So, 20-30%? Ok. Gas Lantern Technique..., I will look up the exact times for it, not sure but will figure out how to program the digital timer to operate this routine. There must be a different light schedule for veg and flower with the gas lantern timing?
2) I didn't have my soil level right up to the top, and maybe this also contributed to the lack of beneficials and the plants not keeping up with the high light levels. Being that I top-dressed with more coots mix medium just two days ago, I'm just going to go forward today with that top-dressing. Had lots of surface roots, likely looking for more medium and beneficial to help their growth.
3) Not sure how much to chop off, but will try to save the healthier growth.
4) Plants aren't drinking, so, yes will top water lightly for next couple of weeks.
5) Will lower temps to 78 and rh to 60-65%rh.

I've added beneficial nematodes twice since transplant as I've had some fungus gnats, but I don't see too many fliers at the moment.

Thanks again LewberDewber, hope to chat some more.
 
It's clear that there's a nutrient issue but I don't see anything that indicates that there's excess light.

When a plan receives excess light, the leaves closest to the light source show the most sever reaction and, as you move away from the light source, the reaction to light levels falls off very quickly because light levels fall off so quickly.

In this grow, if the leaves at the top of the apical stems are receiving too much light, it's almost impossible for the leaves, say, 12" below that to get too much light—the light falls off too quickly.

What's interesting about this grow is that the VPD is smack dab at the level that's too low for seedlings. At this point, transpiration is about 40% lower than your ferts are designed for so a nutrient imbalance is not unexpected.

My approach - increase PPFD to 900-1000µmol and reduce RH until VPD is 1.0

Cannabis thrives at >1000µmol in ambient CO2. My grows hit 700 around week 4 and are at 1k by week 5. The difference in yield between a grow at 700 and 1kµmol is 20% (even Share at migro is finally catching on to this).

Fertilizer concentrations assume that the plant will be at a VPD of 1.0 in veg and 1.2-1.4 in flower. About 50% of nutrients are taken up based on VPD. If VPD is out of range, the concentration of the nutrient solution should be adjusted to suit. If not, the amount of nutrients being taken up will be incorrect and nutrient imbalances may occur. A calcium imbalance is a very common result of VPD being out of range.


1743201156533.png
 
It's clear that there's a nutrient issue but I don't see anything that indicates that there's excess light.

When a plan receives excess light, the leaves closest to the light source show the most sever reaction and, as you move away from the light source, the reaction to light levels falls off very quickly because light levels fall off so quickly.

In this grow, if the leaves at the top of the apical stems are receiving too much light, it's almost impossible for the leaves, say, 12" below that to get too much light—the light falls off too quickly.

What's interesting about this grow is that the VPD is smack dab at the level that's too low for seedlings. At this point, transpiration is about 40% lower than your ferts are designed for so a nutrient imbalance is not unexpected.

My approach - increase PPFD to 900-1000µmol and reduce RH until VPD is 1.0

Cannabis thrives at >1000µmol in ambient CO2. My grows hit 700 around week 4 and are at 1k by week 5. The difference in yield between a grow at 700 and 1kµmol is 20% (even Share at migro is finally catching on to this).

Fertilizer concentrations assume that the plant will be at a VPD of 1.0 in veg and 1.2-1.4 in flower. About 50% of nutrients are taken up based on VPD. If VPD is out of range, the concentration of the nutrient solution should be adjusted to suit. If not, the amount of nutrients being taken up will be incorrect and nutrient imbalances may occur. A calcium imbalance is a very common result of VPD being out of range.


View attachment 5458682
Hi Delps, thanks for your input. If you are going by vpd, I've been pretty close to spot on. My temps varied between 82-84 and as I said my rh was around 70%. That puts me at 1.0. 82-84 and 70%rh is 0.9 and 1.0 on the chart you have. Not sure what your red arrow is pointing to. If there is anything that I feel I've done right its maintaining a decent vpd. I think the nutrient issue I have was not feeding early enough, not realizing that by not filling the container full of soil, the plants ran short of nutrients. I've read your posts about how much the plant loves light. I guess I just need to get feeding with medium and dry amendments at the proper times to run at higher ppfd.
 
I have had similar problems on previous grows, but haven't learned how not to create these issues. Thank you LewberDewber for weighing in. I've seen pictures of your grows and tbh they look awesome, so I respect your opinion on this. Plus, you grow in the same planters, so there's that.

I am going to try to save them. Maybe a bad idea, but running out of supply, and not growing during the hotter months is why I want to work at rescue. Also, i appreciate your honest take, as hearing you'd likely just start over is definitely not what i want to hear, but is an experienced growers assessment which is what I was hoping for. Not that anyone else who chimed in isn't appreciated, but I think your best suited to give your opinion because you use similar methods, but have very nice results.

As far as your advice for moving forward, I'll go through your advice with my further questions now that I have your attention.

1) So, 20-30%? Ok. Gas Lantern Technique..., I will look up the exact times for it, not sure but will figure out how to program the digital timer to operate this routine. There must be a different light schedule for veg and flower with the gas lantern timing?
2) I didn't have my soil level right up to the top, and maybe this also contributed to the lack of beneficials and the plants not keeping up with the high light levels. Being that I top-dressed with more coots mix medium just two days ago, I'm just going to go forward today with that top-dressing. Had lots of surface roots, likely looking for more medium and beneficial to help their growth.
3) Not sure how much to chop off, but will try to save the healthier growth.
4) Plants aren't drinking, so, yes will top water lightly for next couple of weeks.
5) Will lower temps to 78 and rh to 60-65%rh.

I've added beneficial nematodes twice since transplant as I've had some fungus gnats, but I don't see too many fliers at the moment.

Thanks again LewberDewber, hope to chat some more.
I feel ya on running low on buds and wanting to save them. Just understand that may take longer than just cutting your losses.
1) My reason for turning down the light and raising it is to try and limit stress on the plant and see how they respond. As if a plant isn’t healthy again there is no way it can use it all and there will be excess. Make a sick person run a marathon..
2) I left like 2” in mine picker to leave room to top dress WEEKLY (in reality the city pickers don’t hold that much soil) so to counter this you must top dress regularly. Also let the mix “cook” for a couple weeks prior to planting next time. I’m building my confidence as my goal will be to have large 25-30 gal sips someday.
3) Be reasonable with removing that bad growth and do this once they start to respond positively (if they do). U could also do some LST prior to trimming to help encourage lower growth.
5) Ik a lot of growers have had luck with tracking VPD but I have not. So the values I gave you were what mine were throughout veg. I’m flowering rn with about 78 deg and 58rh

GLR worked great for me and I don’t see myself looking back. I didn’t follow its scheduling perfect but again all through veg was just 14-on-4 off-1.5 on -4.5 off.

I appreciate the compliment on my grows but I am a total amateur as well. I’ve had my fair share of grows where I lose a lot of foliage (mostly indoor) but I never turned away from soil bc I love the fundamentals and biology. Good genetics help too. Everything from Twenty20 I’ve ran has killed it indoor even when I fucked up. I just love seed plants bc they grow up in the medium they will remain in.

There are some heavy hitters on this forum tho and take everything you read and apply it YOUR situation and equipment. Trying to measure your variables is great but unfortunately unless you have real calibrated equipment how can you trust it?
I think every soil grower has some gnats just pray they don’t get outta hand lol. I use them little sticky traps.

What light do you have? Also ive never used
coots so there are some pros with that and I’d lean on them for advice there as I’m not a compost expert but again someday hope to be. That’s why I use known soil and mix in extra stuff lightly.
 
If someone could chime in with some knowledge. These plants are in coots mix. Two plants in each SIP. 20% compost, 40% perlite, pumice, and rice hulls. 40% peat moss. Plants transplanted from 1 gal pots to City Picker SIPs on March 2nd. Started noticing deficiency (nitrogen on some, magnesium as well, but mainly on the Gorilla zkittlez) around March 21 and top-dressed with ewc and watered in with fish hydrolysate. Have done a few foliar feeds with Epsom salts, sometimes including TM-7. On March 26 I top dressed with more coots mix medium. The one pic shows a Gorilla zkittlez from Barney's Farm that the leaves curled, and showed what I thought was magnesium deficiency, thus the foliar feeds. I had the ppfd up fairly high (around 700 ppfd), so I've backed the light off a bit. Temps have been between 82-84°F lights on, 76-78°F lights out. Humidity has been fairly high, close to 70%rh lights on, 65%rh lights out. Have lots of air movement (maybe too much) and good extraction with 4" intake, and 6" exhaust with ACI inline extractor fans. No carbon filter yet. I have ordered some calcium nitrate and was going to use it in a foliar feed hoping to balance out the calcim/magnesium as it appears on some leaves, that along with nitrogen deficiency, a calcium deficiency is appearing. Was hoping to get some confirmation on what I'm seeing, and some advice on the use of calcium nitrate in a foliar feed, as in concentration to use. Any help is appreciated.

700 ppfd is way to high for veg. You want to be around 400-500 in veg. Pushing your plants, with that much light, without enough nutrition to support it, I believe will cause deficiency symptoms.
 
I feel ya on running low on buds and wanting to save them. Just understand that may take longer than just cutting your losses.
1) My reason for turning down the light and raising it is to try and limit stress on the plant and see how they respond. As if a plant isn’t healthy again there is no way it can use it all and there will be excess. Make a sick person run a marathon..
2) I left like 2” in mine picker to leave room to top dress WEEKLY (in reality the city pickers don’t hold that much soil) so to counter this you must top dress regularly. Also let the mix “cook” for a couple weeks prior to planting next time. I’m building my confidence as my goal will be to have large 25-30 gal sips someday.
3) Be reasonable with removing that bad growth and do this once they start to respond positively (if they do). U could also do some LST prior to trimming to help encourage lower growth.
5) Ik a lot of growers have had luck with tracking VPD but I have not. So the values I gave you were what mine were throughout veg. I’m flowering rn with about 78 deg and 58rh

GLR worked great for me and I don’t see myself looking back. I didn’t follow its scheduling perfect but again all through veg was just 14-on-4 off-1.5 on -4.5 off.

I appreciate the compliment on my grows but I am a total amateur as well. I’ve had my fair share of grows where I lose a lot of foliage (mostly indoor) but I never turned away from soil bc I love the fundamentals and biology. Good genetics help too. Everything from Twenty20 I’ve ran has killed it indoor even when I fucked up. I just love seed plants bc they grow up in the medium they will remain in.

There are some heavy hitters on this forum tho and take everything you read and apply it YOUR situation and equipment. Trying to measure your variables is great but unfortunately unless you have real calibrated equipment how can you trust it?
I think every soil grower has some gnats just pray they don’t get outta hand lol. I use them little sticky traps.

What light do you have? Also ive never used
coots so there are some pros with that and I’d lean on them for advice there as I’m not a compost expert but again someday hope to be. That’s why I use known soil and mix in extra stuff lightly.
Ive not had one fungus gnat this grow. Normally I see a few buzzing around, but for the most part, I never really have problems with them. It's kinda weird too, because in the sip, the soil is constantly moist. It should be the perfect breeding ground for them.
 
@Nugnewbie I’ve seen lots of suggestions on this thread about what to check, but I haven’t seen anybody mention your soil ph. To me, if there is adequate nutrition in the soil, and your environment is with a safe threshold (which it sounds like it is) that would be my first point of investigation. Why aren’t the plants up taking the food in the soil and why do foliar feeds have minimal effect? I’ve found more often than not soil ph being out of range causing plants to show a number of different deficiencies, which any environmental stress only compounds upon. In soil I have the best luck between 6.1- 6.4 ph.
Do you know what your soil ph is?
 
I actually don't know what the soil ph is, but I don't believe that really is an issue. I believe they were left too long without nutrients, as I failed to top up the planters with medium, or dry amendments. Also, my ppfd has been high.

I've top dressed on Mar 26, 3 days ago, so am going to see if lowering my light and temps for a bit will show improvement.
 
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