no look like old growth yellow - see new growth today at top of cola and it is green… is this a good sign?
2 Likes
Anytime new growth is healthy and green its a good sign 
2 Likes
Will thanks for all your good information and help - maybe you can guide me a little more - so my plant is “healing” so I have not given any nutes in about 6 days - I did flushing with about 7 gallons of water 4 days ago with tap water, all my water sits in an open container for 254hours so any chlorine can evap, I ph the water to 6.7 - 6.8 - so new growth is nice and green and no new discoloring of leaves, actually some leaves recovering - maybe a month left for plant, so I am using fox farm trio and from week 10 on it calls for big bloom and tiger bloom, twice a week… , and flush about 10 days before harvest…, any suggestions on the best way to finish this grow - thanks much Bill
@billybud1232 since you just did a flush, I would ease them back in. And remember, nutrient company wants you to use your nutes up fast so you have to buy more. I never give full strength of what the company recommend
I have been thinking about this and now after taking a second look i’m going to sat you have a
Nitrogen Toxicity
Nitrogen toxicity - too much nitrogen - Cannabis growing problem Dark green leaves, shiny leaves, clawing, weak stems, and overall slow growth. Marijuana leaves that are nitrogen toxic often get “The Claw” or talon-like leaves that are bent at the ends. They also do an odd curving (or cupping) that is often mistaken for overwatering, but is unique to nitrogen toxicity. You can see a “clawing” leaf pictured to the right and more pictures below (click each picture for a close-up).
Leaves that turn into claws often start turning yellow and dying if the nitrogen toxicity is not treated, much like a nitrogen deficiency, only the leaves will continue to get more and more clawed. Leaves eventually turn yellow or brown and fall off. You can tell if yellowing is caused by too much nitrogen because the rest of the plant will be dark green, and the yellowing leaves will turn into claws first.
The majority of times that growers encounter problems with nitrogen, it’s from giving too much of it to their plants.
Many new growers accidentally give their plants give too much Nitrogen, especially in the flowering stage. This results in dark, shiny, clawing leaves.
A Nitrogen toxicity can also cause certain leaves to turn yellow, but other than that it looks nothing like a cannabis nitrogen deficiency?
Your plant needs a lot of nitrogen in the vegetative stage, and it’s generally hard to give too much as long as you’re not going completely overboard with nutrients. Nitrogen is a big part of what makes leaves green, and is incredibly important to the process of photosynthesis (making energy from light).
But cannabis plants need relatively low levels of Nitrogen in the second half of the flowering/budding stage. While your plants still need N (nitrogen) during flowering, too much N at this stage will prevent your plants from forming buds properly, resulting in lower yields, less potency and possibly inferior buds.
This is why it’s important to avoid any type of “time-release” nutrients or soil (for example, standard Miracle-Grow soil) as they will keep giving your plant a lot of N even after its started flowering.
When it comes to nitrogen, this is what your plant needs:
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 systems tend to work well in the vegetative stage.
Some examples of cannabis-friendly one-part Vegetative nutrient systems…
Dyna-Gro “Foliage Pro”
General Hydroponics “Flora Nova 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 “Flora Nova 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.
Different strains react differently to nitrogen toxicity. Some plants get dark green leaves with no clawing. Some strains will get leaves that do the weird 90 degree bend at the tips, while other strains or individual plants start curling like claws and then turn yellow / brown and fall off like a deficiency. Yet these are all signs of too much nitrogen.
Signs of Nitrogen Toxicity
This marijuana plants has been fed too much nitrogen Dark green leaves and foliage
Leaf tips may turn down, without signs of overwatering.
You may notice yellowing on the affected leaves or other signs of nutrient deficiencies as time goes on
Nitrogen toxicity is often but not always accompanied by nutrient burn
The Claw often seems random, affecting leaves here and there
Heat and pH problems will make the clawing worse, as they stress out the plant and lower her defenses, and cause her to drink more water (and uptake more N)
As time goes on, the claw leaves will eventually start turning yellow, getting spots, and dying
This marijuana plants has been fed too much nitrogen
Too much nitrogen causes marijuana leaves to curl down like talonsDark green leaves are a sign of nitrogen toxicity
Image
This cannabis seedling is dark because it was underwatered in a “hot” soil mix (too much Nitrogen), but after watering the plant as normal for a week or two, the plant started growing vigorously
Underwatered in a "hot’ (nutrient rich) starting mix led to this plant developing a nitrogen toxicity
Solution: Reduce the Nitrogen your plant is getting!
Reduce the amount of nitrogen that is being fed to the plants. If you are feeding extra nutrients, cut down that amount. If you are in the flowering / budding stage, make sure you’re using a formula that’s specifically meant for flowering, or else it could have too much nitrogen.
If you are not feeding extra nutrients, you may have “hot” soil that has been giving your plants extra nutrients. In that case, flush your plants with filtered, pH’ed water to help clear out the extra nitrogen.
Effected leaves likely won’t recover, but you should see the problem halt with no new leaves being affected.
Wait! I’m not sure if it’s Nitrogen toxicity!
Nitrogen toxicity in marijuana makes clawed leaves that look like talons Ok, you ruled out overwatering, now what?
When I first got started growing, everyone kept telling me that this particular kind of leaf clawing was caused by under or overwatering my plants, pH problems, or heat problems.
Yet in my case, I knew that it wasn’t over or under watering (I was growing in hydro, where roots grow directly in water and air stones are constantly adding oxygen). I knew it wasn’t pH (my reservoir water had the right pH) and I knew it wasn’t heat since the grow area was slightly cooler than room temperature.
So then what was really causing my claw leaves?
It’s understandable that other growers were mistaken. It is true that many stresses will make any other problem worse.
Plus overwatering can cause a similar kind of leaf clawing (learn more below). And if you do have nitrogen toxicity, than heat or pH problems will make the problem much worse.
Now, you may or may not know that marijuana (or any plant) needs an element known as “Nitrogen” to grow.
In fact, nitrogen is one of the 3 nutrients that are 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 ratio 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.
See the nutrient numbers listed on the front?
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.
For marijuana plants, when they don’t get enough nitrogen, the bottom leaves start turning yellow and dying. Left unchecked, a nitrogen deficiency can cause the whole plant to eventually die.
However, this time we’re the dealing with the opposite problem: nitrogen toxicity, or too much nitrogen.
Why You Should Treat And Prevent Nitrogen Toxicity
Marijuana plants that get too much Nitrogen in the vegetative stage don’t grow as vigorously.
Too much nitrogen is especially harmful in the flowering stage, because this will cause your plant to produce much smaller buds.
If you react quickly and reduce your nitrogen levels at the first sign of toxicity, your plant will quickly recover.
Note: Some strains with the word “Claw” in the name tend to do The Claw more easily than others.
Problems with excess nitrogen are not common in the wild; it’s a lot more common to see nitrogen toxicity on indoor plants, especially when overzealous growers go overboard with nutrients.
Occasionally you’ll come across a strain or particular plant that likes lower levels of nutrients, and when this happens, it’s important to realize the plant is showing signs of toxicity, even if all the other plants in your garden seem fine.
One of the most common signs off too-many-nutrients is “nutrient burn,” or when the tips of your leaf appear brown or burned. Yet there are specific signals your plant will display when she’s getting too much nitrogen…
Recap: How You Know You Have a Nitrogen Toxicity
Dark green leaves and foliage
Leaf tips turn down, without signs of overwatering.
You may notice yellowing on the affected leaves or other signs of nutrient deficiencies as time goes on
Nitrogen toxicity is often but not always accompanied by nutrient burn
The Claw often seems random, affecting leaves here and there
Heat and pH problems will make the clawing worse, as they stress out the plant and lower her defenses, and cause her to drink more water (and uptake more N)
As time goes on, the claw leaves will eventually start turning yellow, getting spots, and dying
Light and “The Claw”
The distance between the leaves to the lights or irregular light patterns from reflectors often seem to affect the condition, which is why many growers believe that light is somehow causing the problem.
You may notice this clawing first appears on dark green leaves that aren’t getting enough light (they aren’t able to use up all their nitrogen and become nitrogen toxic).
The Claw in the Flowering Stage
If you use vegetative plant nutrients during the flowering stage, then they’ll deliver too much nitrogen. This is why you need to get special nutrients meant for the blooming / flowering stage. You’ll notice that flowering nutrients always contain a smaller percentage of nitrogen (the first number) compared to nutrients for the vegetative stage. Learn more about marijuana nutrients here.
Many growers mistakenly keep raising nutrient levels or adding additional nitrogen when they see yellow leaves in the flowering stage, not realizing that it’s natural for plant leaves to start yellowing as harvest approaches. Adding too much nitrogen in the flowering stage can cause nitrogen toxicity even when you can see yellow lower leaves. Nitrogen toxicity in flowering results in smaller yields and airy cannabis buds, so make sure to watch out!
Nitrogen toxic sativa buds Nitrogen toxicity in flowering will reduce bud size Nitrogen toxic marijuana plant in flowering leaves curl down Nitrogen toxicity - too much nitrogen - Cannabis growing problem
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 at harvest from nitrogen-toxic plants with dark green leaves.
It’s Normal For Marijuana Leaves To Start Turning Yellow As Harvest Time Approaches, Don’t Keep Adding More Nitrogen!
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!
I know a lot of marijuana plant problems can look similar, but now that you’re armed with the right information, you’ll know exactly what to do if you see Nitrogen Toxicity affecting your marijuana plants.
Nitrogen toxicity - Dark, curled, claw or talon leaves
Leaf Color:
Edges Appear Brown or Burnt
Yellow Leaves - Lower, older leaves
Dark or Purple Leaves
Brown or Dark Spots
Leaf Symptoms:
Upper Leaves / Newer Growth Affected
Lower Leaves / Older Growth Affected
All Leaves Seem Affected
Leaf Edges Appear Burnt
Leaf Tips Appear Burnt
Spots
Leaves Curl Under
Wilting / Drooping
Plant Symptoms:
Weak Stems
Leaves Curl Under
Plant Wilting / Drooping
Other Symptoms:
Buds Not Fattening
2 Likes
Wow, lots of info… Do you have any experience , or advice on the fox farm trio… I do intend to use them for the balance of grow,. But at a maybe half strength or less, will probably let soil dry out more between feeding and continue to provide molasses during off feeding days and keep pH at 6.7 to 6.9. Sorry to bug you… But you know, kids all grown up so ,this is my baby. Peace. Bill
1 Like
@billybud1232 feed full strength as directed by mfg follow flush schedule as well
Fox farms tends to build up sales s in the soil which is what they hey recommend flushing three times during a grow
Here the schedule just incase you dont have it
3 Likes
Update so , I flushed on 2/20, 2/24, FF nutes at full strength, plus a little cal mag, on 2/28 pH w at 6.7 with molasses, this is how plant looks, I did remove leaves that were in yellow, see tips of leaves turning brown… Hope plant in recovery… Not sure if you can see , but a lot of leave tips brown… Thanks all… This plant has been growing , a full three months , since seed sprout…
3 Likes
Looks like nitrogen deficiency which is pretty typical in flower.
1 Like
Anybody give me an idea how long this plant has to go, been 90 days from sprout… Buds not that big, still developing…I have a month before I go way and will need the plant alone for about 6 days. Tx…
ok thanks, spreading to different part of plant… This has been a long grow for a auto flower. Northern lights… Entering week 12 from seedling… In last two weeks seeing this spread, did a flush over a week ago, but still yellowing …
1 Like
Also my plant is very green and alive… when you look at stems and “underbrush”. Is the buds just sucking the nitrogen out of the leaves? Should I give it a boast of N. Any help appreciated. Bill
I’m no expert so wait for one of the pros to comment but my first thought was that your plant is using the nitrogen since you’re about 12 weeks from seed… so counting little seed growth time and the roughly two weeks stretch you probably have 2 to 4 weeks maximum left? But I couldn’t really see how red the hairs are and your trichome colors etc.
Now if the pros think you should be giving a little bit of nitrogen to change some of the yellowing, that could be possible? But I’m thinking you’re nearing the end of this grow and I don’t know how much they would want you to adjust?
Sorry I’m not of much help I’m learning all of this as I’m going along. Good luck and have a nice morning. that’s a big girl you got there 
1 Like
Thanks brother, or sister for advice , hearing similar things from others, peace
@Countryboyjvd1971. And others, fox farm instructions say flush two weeks till end of grow and then go back to the nute schedule, I guess to harvest… Is this right? Or should I flush and then just use pH water for any subsequent feedings before harvest… Still a few weeks, maybe up to month before harvest. Thanks all
1 Like
Looks normal to me at tjis stage of your grow during middle to late flower the fan leaves will tellow up a fall off as the plant uses up the stored sugars @billybud1232 they are coming ftom low on plant ? Nitrogen should be reduced in flower and calmag should be leftbout of feeding schedule around week six in flower fyi
1 Like
