Leaves falling off

question…I am growing white widow and northern lights. they are in the fourth week of flowering under 1000w hps and 1000w mh. 5 gallon buckets filled with promix. all of a sudden I have noticed the bottom leaves turning yellow and falling off to the slightest touch. each plant is losing 5-10 leaves a day. I feed every other water—about once a week—with half strength fox farm bloom booster. what would make the leaves do this. I am not a beginner and I have never had problems before. please help

Pictures or its all lies… :slight_smile:

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What are your temps and humidity, what is your ph, and you’re run off, and how much are you feeding them, to me if its the very bottom, that’s absolutley normal, now what had me concerned is losing 5-10 leaves a day on each plant

That’s not exactly true, at this point id recommend a support ticket instead of pictures, what are pictures with no valid details or viable descriptions other than what’s been said for now

It’s just a funny way of me asking for more info. :smile:


Gotchya sorry for the misinterpretation

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
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 smile

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ok thanks for getting back to me. first let me say that I am not a beginner and have many years of growing under my belt. I am growing 10 feminized white widow and 8 feminized northern lights that I bought from this seed bank. they are being grown in soil…5 gallon pots full of promix. I have one 1000w mh bulb and one 1000w hps bulb in the flowering room which is about 6’ x 8’. I water as needed or about every three days at which times the plants take about 1.5 gallons of water. every other watering I feed. I use fox farm for the first time this grow. since the plants started to bud (about 4 weeks into 12 hour off cycle) I have used bloom formula. the bottle called for 3-4 tablespoons per gallon and following the directions of this site I gave half that dose or about 2 tablespoons per gallon of water. the ph is staying right in the 6.5 to 6.8 range I keep the temp in the 70’s all the time and have the room well ventilated thus very low humidity. no co2 because I find the plants grow too tall for my room. the bottom leaves turn yellow and fall off. they are very easily separated from the plant----dropping at the slightest touch. I believe I may have a fert burn going on. I enclose no pics because how do you take pics of leaves falling off your plant? at the rate they all going the plant wont have a leave on it in two weeks. the rest of the plant looks good with good bud development but I am afraid the buds will be affected next. any help you can give me will be appreciated.

It’s very likely you have to much light added in your grow room, I have a walk in closet that is 6’x8’x2’ that i use and a 400 watt light is perfect. Now if i get froggy i can add another light being a 1000 watt super hps, but then I need a fan. So what I’m getting out of it if your leaves are going a pale yellow before it’s time to harvest, that means the light in the grow room is too intense.

So figuratively speaking, it just might be helpful to remove the 1000 watt metal halide. As for the nutrient burn, I’m not gunna straight guess it’s a nutrient burn because I don’t have any pictures showing what they are doing it what’s wrong to accurately guess, again if that’s what was going on. Is there any way you can upload a picture to help me help you smile and get a good harvest.

Also, you did mention something about low humidity, how low is your humidity because that can and will affect your plants in flower time…as for the water, your watering the right amount, now as for the feeding id cut it back to once a week chances are there is starting to be a toxic build up in the soil…and also bit of a smart ass answer about taking pictures of the leaves falling off lol. Please don’t take that wrong, take a picture of the color of the leaf and that will help guide me to helping you

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lol ok sorry for the smart ass answer about pictures of leaves falling off. it wasnt meant to be smart but i can see how it came across. i appreciate you trying to help me. with all due respect I don’t think its too much light as it comes out to about 40 watts per square foot. it is probably at the top range for the lights but I have used this for dozens of grows and never had the problem before. what it has given me is pounds of perfect buds every three months. I am only feeding once a week or every other watering so I don’t think that is the problem either. yesterday I removed all of the leaves that had fallen off from my garden. I also removed several that had turned a very pale yellow and fell off as soon as I touched them. today there are dozens of more leaves on the floor of my room. mostly pale yellow some completely dry and brown a few of the lower fan leaves on a few of the plants showed classic signs of nurt burn. brown edges and brown tips. what I believe I did is at the initial watering with bloom formula I used 2.5 tablespoons of the fox farm per gallon of water and I think that kinda shocked the plants. my question is would this leave fall happen from that one feeding of 2.5 tablespoon per gallon three weeks ago? I know I could flush but this would be a logistical nightmare getting these tall full ladies to a place to run that much water through them. my next question is should I quit feeding all together now that I believe they are burnt? again many thanks for your help kind sir.

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This is usually an excess in phosphorus, to be honest with You, I’d try and flush her, then reduce to a lighter dose, now that I have picked your brain that sounds like a nutrient problem, also along shot butmight she be ready for a transplant the could be very possible, she may be dying from running out of room

Also when you get her flushed, let her go about a week without feeding that way you get a direct answer whether it be nutrient burn or some thing else and any time my good sir also my apologies I don’t mean to be a stick in the mud I know your trying to have a sence of humor

Problem: A cannabis nitrogen deficiency will cause the older, lower leaves on your plant to turn yellow, wilt away and eventually die.

The yellow leaves of a nitrogen deficiency may show signs of brown, and they will usually become soft and sort of “fold” in, before turning crispy and falling off on their own.

If the yellowing leaves are at the top of your plant or the yellow leaves are mostly new growth, then you probably don’t have a nitrogen deficiency. Nitrogen deficiencies always affect the oldest, lowest leaves first.

Nitrogen is a mobile nutrient, which means it can move throughout the plant as needed. Cannabis needs nitrogen to keep leaves green and make energy from light. All new leaves get plenty of nitrogen to make them green and help with photosynthesis. The leaves that get the most light are the newest, youngest leaves, so the plant “wants” to give those leaves priority for getting light.

If new leaves aren’t getting enough nitrogen, the plant will start to “steal” nitrogen from the older, lower leaves, so that it can give it to newer leaves. This is what causes the yellowing and wilting of a nitrogen deficiency.

It’s relatively normal for your cannabis plant’s leaves to start turning yellow towards the end of your flowering cycle as the plant becomes nitrogen deficient while creating buds.

However, if your cannabis plant is losing lower leaves fast due to yellowing (if yellowing and dying leaves is “climbing” up the plant from the bottom), especially in the vegetative stage before plant is making buds, you have a problem that you will need to fix as soon as possible.

You don’t want a nitrogen deficiency in the vegetative stage!

A cannabis nitrogen deficiency should be avoided in the cannabis vegetative stage

If you notice your lower cannabis leaves turning yellow in the vegetative stage or in the beginning part of the flowering stage, your plant may be experiencing a nitrogen deficiency which will need to be treated.

It is not good if your cannabis plant is showing signs of an advanced nitrogen deificiency while still in the vegetative stage. It’s normal to lose a few yellow leaves off the bottom of your plant here and there, especially with very big plants. But if you are losing a significant amount of yellow leaves, and the yellowing seems to be moving up the plant quickly, then you have a problem.

Cannabis nitrogen deficiency - yellow leaves are piling at the bottom of the plant

As a grower, you’re interested in how much nitrogen to give your plants at what time. The ratio of nitrogen to other nutrients has a huge effect on growth and bud formation.

Vegetative Stage - higher levels of Nitrogen (pretty much any plant food will do)

Most complete plant foods that you get at a gardening store contain high levels of nitrogen (N). These nutrient system tend to work well in the vegetative stage.

Some examples of cannabis-friendly one-part Vegetative nutrient systems…

Dyna-Gro “Foliage Pro”

General Hydroponics “FloraNova Grow”

Pretty much any complete plant food

Flowering Stage - lower levels of Nitrogen (use “Bloom” or Cactus nutrients)

It’s extra important to find a nutrient system with lower levels of nitrogen for the last part of your plant’s life. Many “Bloom” or “Flowering” style base nutrients are just the ticket.

Some examples of good one-part Flowering nutrient systems…

Dyna-Gro “Bloom”

General Hydroponics “FloraNova Bloom”

If you can’t order online and can’t find a good one-part base Bloom formula locally, you do have other choices. Though not an ideal choice, most Cactus plant foods will contain good nutrient ratios for growing cannabis during the budding stage. So in a pinch, you can use the cactus nutrients that can be found at most gardening stores.

The first cannabis plant pictured below is showing signs of nitrogen deficiency late in flowering; nitrogen deficiency in late flowering is completely normal and even desired. The last picture is an infographic about nitrogen and your marijuana plant.

The signs of nitrogen deficiency (yellowing of leaves) in older, lower leaves is normal towards the end of the flowering cycleInformation about nitrogen and your cannabis plant

It’s normal for plants to show signs of a nitrogen deficiency as the plant gets close to harvest. This is actually a good thing! Too much nitrogen can actually prevent proper budding, and can reduce the overall taste and smell of your plant. This is why all “bloom” and flowering nutrient formulas are relatively low in nitrogen.

So don’t sweat it if you see your cannabis show some signs of nitrogen deficiency late in the flowering stage! Relatively low levels of nitrogen in the late flowering stage helps promote proper cannabis bud development and will increase your yields!

Don’t worry about yellow leaves close to harvest!

It’s normal to see yellow leaves late in the cannabis flowering stage

Solution: You can find many pre-mixed nutrients from the store which contain nitrogen or you could use nitrate of soda or organic fertilizer which are both good sources of nitrogen. In fact almost all plant nutrients of any kind will include nitrogen. If you haven’t been providing any nutrient to your plants, try supplementing your regular nutrients with a bit more nitrogen and see if the plant starts recovering.

If you’ve already been using nutrients, then you probably don’t have a nitrogen deficiency. If you’re seeing the signs of spreading nitrogen deficiency even a week or two giving nitrogen to your plants through nutrients, then you need to figure out what else is causing the yellowing so you can stop it.

More About Nitrogen and Your Marijuana Plants

Sometimes you can get the signs of a cannabis nitrogen deficiency if the pH at the plant root zone is too low, even if the nitrogen is there. This is because when the pH at the roots is not right, your plant roots can’t properly absorb nutrients. If you aren’t sure about your root pH, learn more about pH & growing cannabis plants here.

Nitrogen is especially important during the vegetative stage of your cannabis plants. As your plants start flowering, they will need lower amounts of nitrogen.

Dyna-Gro “Bloom” is a great cheap nutrient choice for the cannabis flowering stageNitrogen is one of the 3 nutrients that is included in almost every kind of plant food.

When looking at plant nutrients, you’ll almost always see 3 numbers listed, like 3-12-6 or 5-10-5. These numbers represent the percentage of Nitrogen (N), Phosphorous (P) and Potassium (K) contained in the bottle. Just about all plant life on Earth needs these 3 elements to grow.

The very first number, “3” in the case of the picture to the right, always displays the proportion of nitrogen in this nutrient bottle compared to the other 2 nutrients (Phosphorus and Potassium respectively).

The reason nitrogen is in all plant nutrient formulations is because it’s vital to plant processes.

Note: During the last few weeks before harvest, marijuana plants starts pulling all the remaining nitrogen from her leaves as part of the bud-making process. This causes yellowing leaves starting towards the bottom of the plant. This is part of the natural flowering process and you don’t need to fight it.You may notice that marijuana leaves are yellowing in almost all pictures of marijuana plants with big buds that are close to harvest. You tend to get smaller yields from nitrogen-toxic plants with dark green leaves at harvest.

Remember: It’s Normal For Marijuana Leaves To Start Turning Yellow As Harvest Time Approaches

Marijuana plant ready for harvest, notice the yellowing leavess, which is a natural part of the ripening processIt’s common for leaves to turn yellow towards the end of the flowering stage, no need to fight it!

Occassionally a nitrogen toxicity is mistake for a deficiency. Could your plant actually be nitrogen toxic?

Nitrogen toxicity

Leaf Color:
Pale Color Leaves
Yellow Leaves - Lower, older leaves
Yellowing Between Veins
Leaf Symptoms:
Lower Leaves / Older Growth Affected
Yellowing Between Veins
Old Leaves Dropping Off
Wilting / Drooping
Plant Symptoms:
Old Leaves Dropping Off

Did some digging and I think this is your problem


Im not experienced marijuana grower but i have grown tobacco my entire life so it would have to be somewhat similar you would think and in my opinion it could be one of 2 things the spoil is getting to hot causing the bottom leaves to burn out which wont affect the bub i dont think i could how ever slightly stun the growth but u said u cut something out cause they were getting to big for ur room anyways which also can lead to a third option too cause the roots could be to big for the bucket causing a lil stress on the plant as well and the other option is their could be microscopic flies eating eating at them theirs these microscopic flies i forget what thier called that live in the hot soil and feed off the bottoms of the plants and theres not alot you can do about it i dont think

Soil gnats. I think that’s what you’re mentioning.

Fungus gnats is the technical term lol


Sounds about right thanks

OK up your feeding dose to full strength. There telling you give me more food there trying to finish


Sorry I am coming late to the conversation. my 1st thought is that in the 4th week of flower and having leaves fall off is the result of the plant using it’s stored nutrition which comes from the leaves 1st. This would cause leaves to fall off. So someone said; 'Increase the Strength of your solution". Good idea.

Another 2 things that can cause this are: Medium too dry; Or, medium too wet. This only applies in a soil grow. I missed the part about how you are growing. Happy growing, lw :slight_smile:

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Thanks @latewood your advise is appreciated late or not