What's new
  • Please note members who been with us for more than 10 years have been upgraded to "Veteran" status and will receive exclusive benefits. If you wish to find out more about this or support IcMag and get same benefits, check this thread here.
  • Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!

Potassium deficient

aimeone

Member
Hello together everyone,

It seems like I’m in bigger trouble as i thought in the beginning. 2 weeks ago I sat my babies in 11l pots with biobizz all mix. I’m not 100% sure if the soil was still perfect, since I reused it from a former grow which I broke up in the 4th week (1,5 weeks in allmix).
I have 4 plants. 2 of them in early stadium of the problem. 2 of them in later stadium. But it all started the same. Little Brown tips in the middle of the Plants growing bigger and spreading with time. But have a look yourself. For me looks either like a potassium deficient or magnesium deficient. Or both. No idea. Would be thankful about every help I can get.
 

Attachments

  • 2A4E0423-433E-416F-9CB9-6F2535614199.jpeg
    2A4E0423-433E-416F-9CB9-6F2535614199.jpeg
    66.9 KB · Views: 29
  • 69F61B62-0419-42F5-882D-063C1E4ABB42.jpeg
    69F61B62-0419-42F5-882D-063C1E4ABB42.jpeg
    69.8 KB · Views: 30
  • 9A45CAAC-6FF5-4399-99EA-9CC21052F805.jpeg
    9A45CAAC-6FF5-4399-99EA-9CC21052F805.jpeg
    68.6 KB · Views: 29
  • 82C8CC29-BBC6-4D2D-A8F4-CA2C615835A1.jpeg
    82C8CC29-BBC6-4D2D-A8F4-CA2C615835A1.jpeg
    66.8 KB · Views: 30

MJPassion

Observer
ICMag Donor
Veteran
Cannabis is known to use Mg like crazy...


Hit those gals (foliar spray) with 1/4tsp Epsom salt mixed into a gallon of water pH'ed to about 6.5.


If the gals don't green up within a few hours then you might give them some form of K from the nutes you are using. Seaweed products would fit the bill.
 

DrDee

Member
Aimeone,
Another scenario is that you are overfeeding causing nutrient salt build-up in rootzone which is locking out K+ (similar in appearance to Mg def.)
JD
 

aimeone

Member
Thanks for your hints up to now. I would say I can exclude overfeeding since I’m growing organic. So no salts.
 

aimeone

Member
Which does not Mean I don’t have a lockout by other purposes. I‘ll try putting the smaller ones in new soil right now. The bigger ones getting a bath in horsetail extract
 

DrDee

Member
Thanks for your hints up to now. I would say I can exclude overfeeding since I’m growing organic. So no salts.

Being an organic grow doesn't exclude nutrient salt build-up. Organic grows merely are an alternate means to provide the plant nutrition. But plants need the salts, whether provided direct (chemical nutes) or indirectly through organic processes.
JD
 

aimeone

Member
Being an organic grow doesn't exclude nutrient salt build-up. Organic grows merely are an alternate means to provide the plant nutrition. But plants need the salts, whether provided direct (chemical nutes) or indirectly through organic processes.
JD

Sorry for the misunderstanding you are right. What I meant to say was chances are low for a overfeeding with organic fertilisers. Also leafes on top are totally fine.
 
T

Teddybrae

Might be a good idea ... seeing as yr re-using soil to check the pH. Unless you flushed the old soil before re-use.

What MJPassion said will give you a quick understanding whether it's Mg or not.

How's yr drainage? Checked it?
 

aimeone

Member
Might be a good idea ... seeing as yr re-using soil to check the pH. Unless you flushed the old soil before re-use.

What MJPassion said will give you a quick understanding whether it's Mg or not.

How's yr drainage? Checked it?

Only used old soil for max 2 weeks. But still not sure if it was ok. There were whole branches inside. Like massive wood.
Checked the roots. The looked fine white even soil was still super Moised after days of not watering. So today the 2 little ones got a new batch of soil. The two big ones got their bath. Let’s see how it works. Thanks so far guys. Wish me luck :) maybe next time I’m gonna go mineral instead of organic.
 

TanzanianMagic

Well-known member
Veteran
Hello together everyone,

It seems like I’m in bigger trouble as i thought in the beginning. 2 weeks ago I sat my babies in 11l pots with biobizz all mix. I’m not 100% sure if the soil was still perfect, since I reused it from a former grow which I broke up in the 4th week (1,5 weeks in allmix).
I have 4 plants. 2 of them in early stadium of the problem. 2 of them in later stadium. But it all started the same. Little Brown tips in the middle of the Plants growing bigger and spreading with time. But have a look yourself. For me looks either like a potassium deficient or magnesium deficient. Or both. No idea. Would be thankful about every help I can get.
Looks a lot more like magnesium deficiency than potassium.

Make sure the roots aren't too cold, and add a little epsom salt.

You may also want to pot up and give them a light solution of bloom food. This will encourage root development and will also help eliminate nutrient deficiencies.
 

slownickel

Active member
ICMag Donor
Veteran
That is a phosphorus deficiency, not potassium and definitely not Mg!!!

What is the pH of your runoff?
 

slownickel

Active member
ICMag Donor
Veteran
Don't use Calmag ever folks. Way too much Mg. Unless your mix is super light with lots of airspace, most don't need any more Mg. If you really think you need Mg, apply it foliarly in the form of Mg Sulfate. Mg is completely translocatable (mobile) in the plant. Most folks have way too much Mg, this causes harshness and scratchy throat syndrome.

What is so funny is that Mg is counter intuitive. You can be drowning in Mg and it will show deficiency, the reason is that the roots are asphyxiated most often. Mg holds up to 15 X it's weight in water. Not good. Most often Mg deficiency is really a lack of air in the mix or overwatering. Took me years to figure this out...

The result is lower Ca in the plant.
 

TanzanianMagic

Well-known member
Veteran
That is a phosphorus deficiency, not potassium and definitely not Mg!!!

What is the pH of your runoff?
It's a close call between Mg and P.

The curling up rather than down of hte leaves could be P.

However, the damage is mainly limited to the tips and fringes of the leaves. Also, the leaves are a very dark green, which is characteristic of Mg deficiency/lockout instead of P. Also, the internodes seem to be very short, and the stems of some leaves are purple, which indicates Mg or K issues. Another problem seems to be is that the plants don't seem to be in flower at all, which is when you can expect P deficiency. So on balance I would say Mg.

So then the question is - why is there Mg or P lockout or deficiency?
 

slownickel

Active member
ICMag Donor
Veteran
It's a close call between Mg and P.

The curling up rather than down of hte leaves could be P.

However, the damage is mainly limited to the tips and fringes of the leaves. Also, the leaves are a very dark green, which is characteristic of Mg deficiency/lockout instead of P. Also, the internodes seem to be very short, and the stems of some leaves are purple, which indicates Mg or K issues. Another problem seems to be is that the plants don't seem to be in flower at all, which is when you can expect P deficiency. So on balance I would say Mg.

So then the question is - why is there Mg or P lockout or deficiency?

This is where a quick soil analysis comes in handy. The rest is called guessing. Without enough P there is little energy, especially if the soil is already full of K, Na and Mg.
 

TanzanianMagic

Well-known member
Veteran
This is where a quick soil analysis comes in handy. The rest is called guessing.
On the other hand, soil or leaf analysis won't show if there is anything wrong with the environment.

The temperature could be too cold, for instance. Or there could be something wrong with the medium.

However for the original poster I would say - first things first, magnesium, epsom salt. At least you can see if it stops the unaffected plants from developing greater mg def.

Epsom salt foliar application is short acting, however it doesn't change the pH of the soil (S) vs soil application.
 
Last edited:

aimeone

Member
Hey guys,
First of all thank you very much for all the comments here. I haven’t been online for a longer time and I just saw yesterday that a lot of you replied. Let me update you what happened in the meantime:

As I explained in the entry post I had 4 plants. The two of them which were in later stadium didn’t grow anymore so I sorted them out, which isn’t that bad since the other two in earlier stadium of the problem filling the whole place.
The two left I treated with 2-3 bathes of horsetail extract which first seem to work in so far that the symptoms were not spreading any further. But like 4-5 days ago I watered the plants with a mix of nutrients and since then it seems like symptoms are spreading again. I already think the problem is connected to our tab water here but let me give you a detailed look in my setup and the environment:

Strain: special Kush#1 (rqs)

Vegi time: 35 days

Flowering time: 7 days

Pots: 11l (2.9 gallons)

Soil: biobizz allmix

Water: I first used bottled water for the first weeks because I had the feeling tabwater was way to hard and to much chlorine, then I used tabwater once and I think this was the time first symptoms appeared (not 100% sure of that) I got back to bottled water but was then told in a German board to go back to tabwater because bottled water wouldn’t be good either, last time I used the tabwater again. I let it stay for 24h to get the chlorid out and mixed it with the nutrients which are supposed to bring down the ph which is higher than >8. Also I think it has a lot of minerals since I can see a white layer after I put it into the cats waterbowl.

Nutrients: biobizz grow 1ml/l, biobizz bloom 2ml/l

Light: hanspanel led 180 w, 12/12, 9 Inch distance

Air: win flex 180 m3/h, fan for air circulation

Temperature: 79 F day, 65 F night

Humidity: between 40-50%

Grow cabinet of 3,9 sqf

If you need any more information just ask.

I made to get up early in the morning where I had the only chance to take some pictures with natural light. As you can see there is a variety of green tones and the funny thing is that the lowest leafes are still in a dark green. The most harmed leafes are the big sun sails from bottom until top.

Since the pots are really light already I need to water today/ tomorrow so any hints are appreciated.
 

Attachments

  • 4EF9EEA8-9C3D-4210-83E7-C097FD5C7173.jpeg
    4EF9EEA8-9C3D-4210-83E7-C097FD5C7173.jpeg
    45.7 KB · Views: 27
  • BBA1A255-FF86-4395-A2FC-DF215B8F4E0B.jpeg
    BBA1A255-FF86-4395-A2FC-DF215B8F4E0B.jpeg
    57.1 KB · Views: 33
  • F7129241-5BAE-4344-8BC1-A5B00A600A74.jpeg
    F7129241-5BAE-4344-8BC1-A5B00A600A74.jpeg
    56.4 KB · Views: 23
  • 84BBBBE4-4711-4C76-964E-26E94676F985.jpeg
    84BBBBE4-4711-4C76-964E-26E94676F985.jpeg
    67.6 KB · Views: 24
  • 1D9103B7-6159-4FF3-A8E7-43CFF7271377.jpeg
    1D9103B7-6159-4FF3-A8E7-43CFF7271377.jpeg
    73.2 KB · Views: 22
  • FECD7F9A-86F7-406F-8C48-815DC6587CBA.jpeg
    FECD7F9A-86F7-406F-8C48-815DC6587CBA.jpeg
    69.2 KB · Views: 25
  • 02B819F4-7D3E-4045-8540-F2802D6D314B.jpeg
    02B819F4-7D3E-4045-8540-F2802D6D314B.jpeg
    72.1 KB · Views: 29
  • 5B3B99F4-E2EE-4B69-B826-C09767BA4AFE.jpeg
    5B3B99F4-E2EE-4B69-B826-C09767BA4AFE.jpeg
    70.7 KB · Views: 29
  • E889FF1E-C67C-47F5-901C-9E702B8BAA25.jpeg
    E889FF1E-C67C-47F5-901C-9E702B8BAA25.jpeg
    71.4 KB · Views: 29
  • image
    image
    106 KB · Views: 39

aimeone

Member
Two more
 

Attachments

  • AFE94FAB-3C3B-4DE8-B80F-C10D27995E7C.jpeg
    AFE94FAB-3C3B-4DE8-B80F-C10D27995E7C.jpeg
    70.7 KB · Views: 24
  • B6A0DB55-F5BC-468C-871C-8061A9CE9955.jpeg
    B6A0DB55-F5BC-468C-871C-8061A9CE9955.jpeg
    70.2 KB · Views: 26

aimeone

Member
I researched a little bit more about the waters I used in the past. It looks like they were all way to hard with to much minerals. Can this cause the deficiencies?
Thinking about to mix some bottled water with demineralised water. What do you think?
 

Latest posts

Latest posts

Top