AK-48 issue: Nute burn or Potassium deficiency or am I off?

Hi, this is my first grow and I’m at flowering stage 19 days . Starting to be worried about those burnt tips that are also slowly getting on the sides of the leaves at any height of the plant. Tried to find tips online on good sites and i think this is either a lack of potassium or nutrient burn but I’m really unsure about this. If I’m completely honest since halfway of this adventure i’m weekly adding a reduced dose of 20-20-20 fertilizer I also did add a single dose of 7-15-30 (bud+) about one week into flowering. Typical temp is 75F 38%. Please, could anyone take a look and provide input on how to adress my situation.

Your help is really appreciated.

To get really accurate help, fill out a support ticket (at the beginning of the Forum). It could be numerous things with pH and Nute burn being at the top of the list but it depends on what you are growing in also. Fill out a ticket and the Pro’s here can help you with your grow. God luck on your grow. AK-47 was my favorite grow so far, and White Widow.


Strain; ak48 feminized, 3 in pots 1 in a smartpot

Soil in pots

3x3 growtent

PH of runoff or solution in reservoir? NA

What is strength of nutrient mix? EC, or TDS, info to come this evening


Light system, mh400w veg 18/6, hps400w in flowering 12/12

Temps; Day 86F, Night: mesurement to come

Humidity; Day:40%, Night: mesurement to come

Ventilation system; variable blower on a carbon filter at low speed

AC, Humidifier, De-humidifier: 2 basic stationary fans

Co2; No

(PH) it looks to be a lockout the droopy leaves burnt tips all point to root zone problems If the ph is out won’t matter what you feed them the roots won’t absorb it.

Been gathering advice from many sources, currently the most recurring has been nute burn. I will try to flush, rase the pH of the water a bit and stick to just water for a while.

It does look like a nute burn, and the leaves being almost too dark green would also support this. However, pH can also cause nute burn like symptoms, pH is completely connected to the availability of nutrients, pH can make nutrients unavailable, or way too available, to the point of “burning” or being toxic to the plant.

Happy growing,


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Thanks a lot for the interesting new informations about the runoff and all pigSquishy.

I’m waiting to receive a decent ph meter, I’m not good at trusting strip for reliable results. In the meantime I flushed all four, (3 pots + the smart pot) with dechlorinated water. Do you guys think I can expect a somewhat successful harvest even with this situation?

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Indeed they call it weed for a reason it is quite forgiving and hardy broke a main stem 3/4 through 3 days ago while doing some LST scratched the branch by accident and the stress cracked it almost clean off. I simply left it since I had no room for 3 more clones within 2 days it was facing back up and thriving like nothing happened will need to stake it during flower but otherwise like it never happened.


Sorry I have been laid up so I didn’t get back to this.
pH is very important and a good meter is valuable in keeping your pH under control. Amazon and E-bay have a bunch of good meters for a reasonable price. I picked up a Mudder pH meter for about $10 (you can get a pH meter and TDS meter in pairs for around $20) and has worked well for me. The pH unknown is really a problem as you really do not know which way to go.
Are you adding 20-20-20 during flowering? That can definitely cause problems. A little nitrogen in flowering is OK but a lot will also cause problems during flowering.

I also noticed that your daytime temperature is a little high in your tent. That could lead to problems also. Just something to keep in mind. Sometimes as little as getting a higher flow of air will help lower the temp also. My first grows were full of these problems so do NOT let this bother you. Despite all we do, we usually come out pretty well. Hang in there and keep trying, the rewards are right around the corner.
Good luck on your grow’s finish.


Currently, the pH reading I have is from ph strips is about 6.2 and the water used for the plants is tap water thwt I always let it rest 24h to help dechlorinate. Many peaple talked about pH, I think it’s time for a real meter.

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if you want to declorinate water faster try using an air pump bubbler set up will also make it easier to stablize your ph before using water which is hard or has considerable buffers in it will be harder to ph correctly. If feeding add nutes first then test water most nute are acidic so will lower ph but also react with minerals in your water so your readings can change in minutes I like to let things settle and adjust for 10min before testing again then using if still on par. I also test my runoff to make sure what I put in is what comes out or atleast putting my roots in optimum ph

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Getting worried a bit. Lots of leaves dying. I know that it’s normal to loose some in flowering but my precious are looking sick.

pH, pH, pH!

It is almost certainly pH.

What is the pH of the water you are giving it. And what is the pH of the run-off?

This absolutely looks like pH lockout related.



Just received my ph meter but not my calibrating solution. My water’s ph is at 7.4. Did not analyse runoff yet. Not nutes or fertilizer added since original post.

Harvest time over, final curing stage in jars almost done. Got ourselves about 130g of good flowers for four plants.

Happy with this first grow. I’ll go with another batch of ak48 before going into more delicate strains but this time 0 fertilizer unless needed. Thank you all for your time and advice.

MacG is correct, and it caused this to happen

Manganese (Mn) Micronutrient and Immobile Element

Manganese Helps enzymes break down for chlorophyll and photosynthesis production, as well as it works with plant enzymes to reduce nitrates before producing proteins.

Having plants that are deficient in manganese can turn the young leaves into spotted (mottled) yellow and or brown areas on young leaves. Dead (Necrotic) yellow spots form on top leaves, while the lower older leaves will or may have gray specks and or spots. Symptoms can include yellowing of leaves while the leaf veins can stay green. Can also produce a chequered effect. As the plant gets newer growths the plant will seem to grow away from the problem, that’s why the younger leaves may be unaffected. On the top of the leaves, brown spots can appear. While the severe areas of the leaves turn brown and wither. Parts Affected by a Manganese deficiency are: Young leaves.

Too much Manganese in the soil will cause an iron deficiency. The blotchy leaf tissue is caused by not enough chlorophyll synthesis. Your plants will seem to have very weak vigor caused by the excessive amount of manganese.

Problems with Manganese being locked out by PH troubles

Soil ph of over 6.5, High iron soils, Low nitrogen Soils, Dry weather
and compacted soil.


Manganese gets locked out of soil growing at ph levels of 2.0-5.0
Manganese is absorbed best in soil at a ph level of 5.5-6.5 (Wouldn’t recommend having a soil ph of over 7.0 in soil) anything out of the ranges listed will contribute to a Manganese Deficiency.

Hydro and Soil less Mediums

Manganese gets locked out of Hydro and Soil less Mediums at ph levels of 2.0-4.5
Manganese is absorbed best in Hydro and Soil less Mediums at ph levels of 5.0-5.6 (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 manganese deficiency.

Solution to fixing a Manganese deficiency
Foliar feed with any chemical fertilizer containing Mn., or mix with water and water your plants with it. Any Chemical/Organic nutrients that have Manganese in them will fix a Manganese deficiency. (Only mixing at ½ strength when using chemical nutrients or it will cause nutrient burn!) Other nutrients that have Manganese in them are: Manganese chelate, Manganese carbonate, Manganese chloride, Manganese dioxide, Manganese oxide, Manganese sulfate, which are all fast absorption. Garden Manure, Greenssand are both good sources of manganese and are medium/ slow absorption.

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.

Manganese deficiency in flowering.

Do you see how similar his photo is to this one.


just my 2 cents worth and to late to help this time .but if it happens again try this if you can , lower temps 75-80F and try adding CalMag ,add to only one plant at the first signs of this that way you can compare the difference for your self .1-2 weeks in soil OR 1 week hydro will tell if its a cal mag. deficiency also unless you use co2 ,temps 85 and above stop or Slow them way down .

Now that you posted the later stage piks. It is definitley a toxidity due to your formula. 20-20-20, + 7-15-30 or, whatever that NPK rate was is too much for the plants.

PH is almost for sure a strong contributor to the issue. So; Too strong fertilizer and no clue as to what the PH is; Is the main reason for your issues.

Another thing I saw above. You posted that you have plants in a 3" pot; Or did you mean 3g pot. 3" is only good for seedlings before you transplant to bigger pots for veg phase.