Ca deficiency?

My auto is showing some deficiency, I think it's Ca? Rusty and dried tips on the leaves. Last week she was totally healthy. Feed is the same as last week, 2ml Ca (1-0-0 which has 3% Ca) and 2ml Sensi bloom A/B (5-4-8 which has 2% Ca). Right now I bumped Ca to 3ml and base nute is the same at 2ml.
She's 3 weeks from finish.

Growing in coco under DIY COBs, temp is 22-30°C and RH is 50-60%.
Maybe I have too much light there? Last week I increased it to 220W at wall (so driver is around 30W), I have 80x80cm tent, so around 30W/SQF or 26-30 MOL.

Also maybe could @Randomblame come in, please?

Going with the 3 weeks from finish, looks like they are just dying off as normal. Reclamation/decay that starts at the tips and works its way back is usually the plant moving mobile elements to upper leaves.

KonopCh said:

My auto is showing some deficiency, I think it's Ca? Rusty and dried tips on the leaves. Last week she was totally healthy. Feed is the same as last week, 2ml Ca (1-0-0 which has 3% Ca) and 2ml Sensi bloom A/B (5-4-8 which has 2% Ca). Right now I bumped Ca to 3ml and base nute is the same at 2ml.
She's 3 weeks from finish.

Growing in coco under DIY COBs, temp is 22-30°C and RH is 50-60%.
Maybe I have too much light there? Last week I increased it to 220W at wall (so driver is around 30W), I have 80x80cm tent, so around 30W/SQF or 26-30 MOL.

Also maybe could @Randomblame come in, please?

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I would not worry about it, buddy, it's only three weeks to finish and there is no way to solve it.
To me, it looks a bit overfertilised and deficient at the same time.
Looks like too much N (leafs are realy dark green) which can lock out Ca. (rusty spots).
I would like to see more pics and shots of the whole plant and some of the older leafs.
Is the whole plant lookin so dark?

BTW, nitrogen moves quickly in the plant and migrates from bottom to top, causing leaves from below to turn yellow. This is normal behavior most of the time in the last few weeks. Calcium moves very slowly inside the plant and tends to concentrate in roots and old leaves. A calcium deficiency first shows up in the upper and middle areas when new leafs get not enough Ca. and damage occurs in the cell walls.

Calcium is hard to absorb at lower pH's, so I recommend that you let the pH drift from 5.8 to 6.3 before refilling the rez.
In this way, you ensure that once the one and once the other nutrient can be better absorbed.
Possibly there is a salt build-up in your coco, especially too much N would cause such a Ca. lock-out.
Did you check PH/EC of the outcoming drain?

I am worried because it happened in 3-5 days. And I doubt they will sail smooth another 21 days. I want to fix this.
I don't think it's too much N, she's pretty in colour, not too dark.

Here are some pics when lights are off:

Randomblame said:

BTW, nitrogen moves quickly in the plant and migrates from bottom to top, causing leaves from below to turn yellow. This is normal behavior most of the time in the last few weeks. Calcium moves very slowly inside the plant and tends to concentrate in roots and old leaves. A calcium deficiency first shows up in the upper and middle areas when new leafs get not enough Ca. and damage occurs in the cell walls.

Calcium is hard to absorb at lower pH's, so I recommend that you let the pH drift from 5.8 to 6.3 before refilling the rez.
In this way, you ensure that once the one and once the other nutrient can be better absorbed.
Possibly there is a salt build-up in your coco, especially too much N would cause such a Ca. lock-out.
Did you check PH/EC of the outcoming drain?

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Yes, I know about N and Ca, that's why I think it's Ca deficiency. Because upper leaves are affected. I know about fading and yellow leaves when the end approaches.

I let pH drift from 5.7 to 6.4, I am using autopots so drift is 100%. That also means, I cannot flush.

She's 61 days old today, I will let her go till 82 days. Around that time (50-60 days) I always get some troubles, but never tried 3ml Ca. This last feed yesterday, I tried it. Other than that, I don't think what can I do. IF that's really Ca deficiency.

KonopCh said:

Yes, I know about N and Ca, that's why I think it's Ca deficiency. Because upper leaves are affected. I know about fading and yellow leaves when the end approaches.

I let pH drift from 5.7 to 6.4, I am using autopots so drift is 100%. That also means, I cannot flush.

She's 61 days old today, I will let her go till 82 days. Around that time (50-60 days) I always get some troubles, but never tried 3ml Ca. This last feed yesterday, I tried it. Other than that, I don't think what can I do. IF that's really Ca deficiency.

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Ahh, okay! But I don't think more Ca. will help.
If it occurs more often and always at the same time, then I am pretty sure that salts have built up. There are products such as enzymes that help to break down salts build-ups when used regularly, but there are also products that are specifically used in case of over-fertilization/salt build-up.
FloraKleen from GeneralHydroponics is such a product which solves salt build-ups and converts them into sugars.

Being in autopot, plants feeds through tray with nutrient solution from bottom. It's logical/useful if enzymes are applied that way? Or they must be in touch with roots, so applied from above?

Florakleen is same as Drip clean, which prevents salt buildup in lines. I use Drip clean, but as I understand, this prevents salt in lines not in medium.

Funny thing is (but it's possible) I stay at 1.5-1.7 EC in full flower, 0.2 of that is water. And I almost every time get his "salt build up".

So, we agree that this is not from too much light? Looks crispy a little.

Beautiful girls by the way!
The dark green only came over so strong on the first picture! In fact, it does not look like it in the other pictures.
What surprised me is that it went so fast, 3-5 days without advanced warning.
Have you changed your fertilizer mix? Or used another/a new product? Mixed calcium products could flocculate so they are no longer available to the roots.

Agreed! Not too much light!
Hmm, are you sure? I don't think FK is the same as DripClean it is specially made to use in the last few weeks in all mediums. It can be used between the runs, below the description:

"FloraKleen is ideal for final rinsing a few days before harvest.
So you promote the ripening and activate the sugar production again.
With FloraKleen you make sure that the plant is freed from all fertilizer surplus.
So you get a clean and tasty harvest.

Unlike similar products, FloraKleen is not enzyme-based.

It can also be used between crops for purifying hydroponic systems.
FloraKleen can be used in all substrates (such as soil and coconut) as well as in hydroponics throughout the life cycle of the plant.

Mode of action of FloraKleen during culture:

dissolves accumulated salt deposits
reduces stress caused by excess fertilizer or unbalanced nutrient ratio
breaks down unwanted nutrient connections between mineral salts and substrates, thus increasing the availability of nutrients
serves as a food for the microorganisms present in the substrate"

As I said, feed was the same last 14 days.
Yesterday I just upped Ca to 3ml, because I think it is Ca deficiency. Hope that will help.

Really want perfect grow without troubles and deficiencies. I know they will be okay, but that's not nearly perfect like I want.

You could change from autopots to a DTW system. This reliable avoids salt build-ups because of the small drain every feeding. Many think it is waste, but in fact it is more economical than most of the closed systems.

P.C. is very informative in its thread and its results speak for themselves.
And the thread has only a few pages ..

https://www.rollitup.org/t/strip-leds-in-the-garden-of-paradise.954799/

KonopCh said:

Yes, I know about N and Ca, that's why I think it's Ca deficiency. Because upper leaves are affected. I know about fading and yellow leaves when the end approaches.

I let pH drift from 5.7 to 6.4, I am using autopots so drift is 100%. That also means, I cannot flush.

She's 61 days old today, I will let her go till 82 days. Around that time (50-60 days) I always get some troubles, but never tried 3ml Ca. This last feed yesterday, I tried it. Other than that, I don't think what can I do. IF that's really Ca deficiency.

Click to expand...

You solved your own problem and pointed out the issue with bottom feeder systems.
Probably reducing your ec in general would do a lot to help, maybe 1.1 - 1.2 tops knowing that you will be having nutrient accumulation pushing things up from the bottom?

What's the distance between you're leds & the canopy & what's you're ec?

@OneHitDone but looking at plants, they're light green which means they don't receive enough feed? EC is 1.7 now maximum, because they're close to finish. Weeks before it was smaller.

@kushedy 45cm from net, and at least 15cm from colas. But this plant on pictures has smaller colas, so light from her tops is at least 20cm. EC is 1.7 now maximum, because they're close to finish. Weeks before it was smaller.

I grow in Autopots with cobs as well. I've seen that on my plants a few times. It's generally happened when I have run out of vertical space & my plants have got to close to my LED’s.


There have been a few threads on RIU to do with hanging distances, light stress & intensity.

Some people find they need at least 30cm between the top of their plants & their lights, others need a good 40cm between them. I could be wrong here but from what I have read the intensity of the light being so close causes you’re plant to try & keep up with the light intensity by ploughing through nutrients. It may be able to keep up for some time by munching through feed at a high pace but the slightest lacking in an element causes it to fall over or it could be that you have increased your EC so much to cover you’re plants extra demand for certain elements that it has inadvertently caused a lock out of another element.


As long as I manage my plant height & keep a good 40cm between my LED’s & plants I don’t have this problem. That is my experience to date. Your EC sounds to high for a few weeks before harvest. I’m normally down to around 1.0 - 1.2EC at that stage & my water background ec is 0.5.


If I were you I would raise the hanging height, reduce the EC down to around 1.2 & continue as you would normally. Your plants aren’t going to heal at this point so your best bet is to give them the easiest conditions to survive in & adjust your environment on your next crop.


Sorry just re-read your first post. The Ca product you were feeding at 2ml & then bumped to 3ml. What product is that? Is that a calmag product or some sort of standalone calcium only product?

@kushedy thank you for answer, I will try this. Ca product is basically CalMag supplement, which has Ca nitrate (3%) and Mg nitrate (1%) and a little iron DTPA. I am reading guys are supplement a lot of Ca to plants, but whenever I asked them how much it "a lot", they couldn't answer me. So basically broscience from them. I want to compare results or products by numbers, not only by "a lot of Ca"...

May I ask you how many plants you have, what tent and how much light (PPFD, MOL)?

No worries @KonopCh. I’ve just dug out the old bottle of calmag I was using before I switched to Calcinit & Epsom salts. The Calmag I was using was 4.5% Calcium & 1.75% Mag (Vitalink Calmag). I used that at up to 1.5ml per litre & would take it down bit by bit to 1ml per litre towards the end of flowering.

All strains & grow environments are different so what worked for me may be a little too much for your plants or not enough. You’ve just got to experiment bit by bit with it. Maybe start at 0.5ml per litre for very small plants & as they grow take it up to 1ml per litre. From there judge if they are growing well enough or give them a tad more to see if that perks them up.

I keep an excel spreadsheet noting everything I give my plants day by day. I can see what I have dosed plants with going back over a year now. Its very handy when trouble shooting & fine tuning what I feed my plants. May be worth you keeping some sort of record of what you give your plants so you can see what does & doesn’t work.



I have 2 indoor grows going. One is a 2x4 (2 plants) & the other is a 2x2 (1 plant). I’ve got 8 x CXB3590’s in the 2x4 & 4 x CXB3590’s in the 2x2 all 3500k. I grow scrog style due to my grow environment being vertically challenged. I veg in a small tent using a DIY Samsung strip build I threw together.

At the moment I have no idea what the PPFD etc is. I’ve literally just harvested the last run & have just got the next 3 plants in situ so have them under 50w per plant at the moment. I’ll be flipping them this weekend so will slowly start increasing the wattage bit by bit.

Also, I don’t have a par meter, only got a lux meter. Since I realised that 40-45cm hanging distance was the sweet spot for my environment I haven’t really bothered taking lux readings (getting lazy). The plants seem to be happy enough at anything from 25-40w per cob at that height. Haven’t needed to use more wattage that that. I could probably get away with 30-35cm hanging height with 25w per cob but I get better growth throwing down more wattage from a slightly higher level.

Hope that is of some help to you.

You are in the same situation like me. I know different plants and environment cannot compare.

- I slowly increase nutes and Ca/Mg to 2ml/L (as I said, this time I tried with 3ml/L)
- I write in excell
- I have 2.5x2.5 tent (80x80 cm) and 6 COBs, each driven at max. 35-40W in peak flowering
- I keep distance 20cm or more above top of colas and 45cm above SCROG
- I can get 375g dry buds in that space

Ahhh... I will just try lower EC to 1.2 next time, and let's see if I get the same "lockout" (or whatever this is) around 3-4 weeks till finish. As three guys here tell me the same, I must try this now. Because everything else looks okay to me (pH, temperature, RH, VPD, light intensity).

One question to @Randomblame: DTW is top feed only, right? This is not option for me then.

@KonopCh I meant 40-45cm hanging distance from the top of your highest cola. The distance you hang your lights above your net is irrelevant. Hanging your lights 20cm above your buds is why you are experiencing this problem. Most go with anything from 30-50cm above the tops of they're plants. Depends on what you're plants can handle. In this instance you're plants are starting to struggle with 20cm from canopy.
Best of luck