Is it lack of phosphorus, potassium, or both?
The buds are looking good, and I want to keep it that way.
My cheapo PH meter says the soil is about 7, but it always says that, on all the plants, so I don’t know how reliable it is.
Looks kind of like potassium based on the pictures but I’m just guessing. Here’s a chart but I’m sure someone will be along to give more experience feedback.
I would call it a potassium issue as well, but only going off of the diagram. I’m not an experienced enough grower to be able to diagnose with certainty.
I’m sure someone with more experience will chime in soon.
Oh they are on that way but isn’t guessing fun!
The people I know ow that are coming need as much info as you can provide about your grow @MWahl
You obviously are missing something with your nutrients. What is the strain and what nutrients are you giving her. I hope you respond tonight to save your plant. Those leaves are goners so be proactive.
COPY/PASTE the below list into your forum post.
Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA
- Strain; Type, Bag seed, or NA
- Soil in pots, Hydroponic, or Coco?
- System type?
- PH of runoff or solution in reservoir?
- What is strength of nutrient mix? EC, or TDS
- Indoor or Outdoor
- Light system, size?
- Temps; Day, Night
- Humidity; Day, Night
- Ventilation system; Yes, No, Size
- AC, Humidifier, De-humidifier,
- Co2; Yes, No
If you can, upload a picture of your plant. It helps the diagnosis, if needed.
Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you
Please fill this out are you in pots or directly in soil
7 a bit high have you tried calibrating the meter to test its accuracy what type of meter is it those dual probe soil types never work
Those few points between 6.8-7 can lock you out and if it’s not accurate who knows what the actual ph level is
I’m a bit busy at work and haven’t been on much this week but fill ticket out so we have accurate info
Definitely looks like potassium issue to me as well
Or combo of both
With info provided Iwill say the ph is way off and locking you out @MWahl
It appears to be a lockout of nutrients. Most likely your PH is too high (guess) or you have a root bound issue (can’t see your growing vessel).
You have some talent tagged so maybe we can figure it out. The support ticket info will gleen a wealth of information…
First I would like to welcome you to ILGM
Your problem is> Potassium (K) Mobile Element and Macro Element
HERE IS A PIC OF POASSIUM
Potassium plays a big role as well. Having good amounts of potassium in your
plants helps in having sturdy and thick stems, disease-resistance, water
respiration, as well aids in photosynthesis. Potassium is also found in the
whole plant. It is necessary for all activities having to do with water transportation.
Potassium is necessary for all stages of growth, especially important in the development of Buds.
Having to little of Potassium in your plants causes the plants leaves to show
retarded growth and show a scorched tip and edges around the leaves. Plants may
stretch and your branches can be easily broken or weak. Don’t get this deficiency
confused with iron, because it almost acts like iron but to tell the difference
in the two is: for potassium the tips of the leaves curl and the edges burn and die.
Older leaves may show a red color and leaves could curl upwards. Dead patches (Necrosis)
can happen on the margins of larger fan leaves thus, the leaves will eventually die
off and turn brown. The Older leaves will show different patches of color (mottle)
and turn yellow between the veins, following by whole leaves that turn dark yellow
and die. The plants overall growth slows down, mostly when they are in vegetative stage.
To little amount of potassium also slows the growth of buds during flowering stages.
Dark edges will appear around the edges of the leaf when the deficiency is starting
to happen. When your Relative humidity is low, you can almost bet your going to soon
get a potassium deficiency from your plants perspiration.
Potassium can get poorly absorbed when having too much Calcium or ammonium nitrogen,
and maybe cold weather. Having to much sodium (Na) causes potassium to be displaced.
SO keep those in mind… Parts affected by a Potassium Deficiency are:
older leaves and leaf margins.
When you have too much Potassium in your soil, it can lead to big troubles, like
salt damage and acid fixation of the root system, as well as too much potassium
can cause a calcium deficiency. Your fan leaves will show like a light to a dark
yellow to whitish color in between the veins. Due to a molecular imbalance,
potassium toxicity can cause a reduced uptake and lead to the deficiencies of Mg,
and in some cases, Ca. Also leads to the other nutrients to not be absorbed properly
leading to lots of other deficiency such as: magnesium, manganese, zinc and iron and
can cause problems with calcium as well.
Problems with Potassium being locked out by PH troubles
Soils with excessive Leeching and High ph soils and or water.Soils that are
potassium fixated. An excess of kitchen salts (sodium) in the root system/enviroment.
Potassium gets locked out of soil growing at ph levels of 4.0-5.5
Potassium is absorbed best in soil at a ph level of 6.0-9.5. (Wouldn’t recommend having
a ph of over 7.0 in soil) anything out of the ranges listed will contribute to a Potassium deficiency.
Hydro and Soil less Mediums
Potassium gets locked out of Hydro and Soil less Mediums at ph levels of 4.0-4.5, 6.0-6.5.
Potassium is absorbed best in Hydro and Soil less Mediums at ph levels of 4.7-5.3, 6.7-8.5.
(Wouldn’t recommend having a ph over 6.5 in hydro and soil less mediums.) Best range for
hydro and soil less mediums is 5.0 to 6.0. Anything out of the ranges listed will contribute
to a potassium deficiency.
Solution to fixing a Potassium deficiency
Any Chemical/Organic nutrients that have potassium in them will fix a potassium
Again Peters All Purpose plant food 20-20-20, will cure the potassium deficiency ,
Miracle grow Tomato plant food, Miracle grow All purpose plant food.( Only mixing at
½ strength when using chemical nutrients, or it will cause nutrient burn!) Some other
supplements of potassium are: Wood ashes, which are fast absorption, Kelp Meal, which
is medium absorption, Greensand, which is slow absorption, granite dust, which is slow
absorption. Sulfate of Potash, Sulfate of Potash Magnesia, Muriate of Potash, which are
medium absorption. FOXFARM GROW BIG HYDROPONIC CONCENTRATE, which is fast absorption.
(FFGB can bring your ph down as well) Earth Juice Meta-K, which is fast acting.
(Can bring down your ph as well) Leaves will never recover, but the plant will show
recovery after about 4 to 5 days when using a fast acting nutrient.
Note: Wood Ashes, can make your ph go up a bit, so please monitor your ph when using it.
Now if you added to much chemical nutrients and or organics, (which is hard to burn your
plants when using organics) you need to flush the soil with plain water. You need to use
2 times as much water as the size of the pot, for example: If you have a 5 gallon pot and
need to flush it, you need to use 10 gallons of water to rinse out the soil good enough
to get rid of excessive nutrients.
It does look like potassium, but I suspect there is a potassium lockout from incorrect ph. Get your Ph meter working so you can properly correct the Ph and it should fix the problem. Just adding potassium will not help.
I agree @raustin ph needs to be corrected
I agree, theres more than one nute missing so PH would be a good start.
Wow, thanks to everyone who replied! I’ll reply to this one since it has questions I can answer…a couple anyway.
Strain: Frank’s Gift, from a clone.
Outdoor, in 100 gallon smart pots, coco. I should add that this soil is supposedly specially formulated for cannabis growth, I didn’t compile it myself.
I think most of your other questions would refer to indoor or hydro?
Can you define EC and TDS?
PH is reading between 7 and 8…for whatever this $12 meter is worth. As you say, it’s dual probe and probably junk.
If I need to adjust the PH, would it be up or down? I understand I can buy PH adjustment stuff at a grow store.
Here are some additional photos:
I’m having similar problems with a couple of other plants:
On this one the leaves just started dying from the bottom up. Buds are way behind the other plants in development. I’m thinking I might lose this one, but I hope to save it.
And another plant in a 20 gallon pot- not exactly the same in appearance.
I have two other plants That are doing much better than these, same conditions, 100 gal smart pots.
Should I also use a fertilizer with more potassium ratio?
Thanks again, this is all immensely helpful.
The soil pH meter is a piece of crap. I have the same one and the only thing I found useful is the light meter which really only tells you if the light is bright enough. It looks to me like your plants are pretty healthy for “guessing” at the pH levels. Most of us use a pH meter that you can buy on Amazon.
The one thing I have burned into my brain is that the pH has to be in balance or you’re going to have problems with the Grow
Have you done a slurry or a run-off test?
If your ppm is reading high, it could be nutrient lockout. If that’s the case, flushing would fix the problem.
Coco is very forgiving. If the ph is high and your ppm is high, you need to flush immediately. No more nutes yet.