Question from a fellow grower:
Need more info. Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so; Or post
NA (non applicable)
- What strain, Seed bank, or bag seed
- Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF
- Vessels: Pots, Grow beds, Buckets, Troths
- PH of Water, Solution, runoff (if Applicable)
- PPM/TDS or EC of nutrient solution if applicable
- Indoor or Outdoor
- Light system
- Temps; Day, Night
- Humidity; Day, Night
- Ventilation system; Yes, No, Size
- AC, Humidifier, De-humidifier,
- Co2; Yes, No
Always try to upload a clear picture of any issues you may have to allow the community to assist you.
Add anything else you feel would help us give you a most informed answer should be included. Feel free to elaborate, but short and to the point questions and facts will help us help you in a more efficient manner
Could be white powder mold. Unless
Diatomaceous earth was sprinkled on the leaves. Generally a lack of good air circulation is the culprit to this. Ventilation fan, and fan inside grow area moving air around is highly recommended. With out further details this is the best I can advise.
Kinda reminds me of spider mites. Did you look under the leaves and is therfe any webbing? Is it worse towards the bottom? They seem to work their way up.
Boy, oh boy that’s White Powdery Mildew,
Your marijuana plants need 18 essential elements. They get carbon, hydrogen,
and oxygen from atmosphere and water. They get the 15 other elements via their
roots. These elements are sometimes grouped as major, secondary, and trace elements.
The groupings are determined by how much of each element is needed–some are needed
a lot more than others, but all are necessary.
The major elements are nitrogen, phosphorus, and potassium. The so-called secondary
elements are magnesium, calcium, silicon, and sulfur. Some people group these seven
elements as “macronutrients” because they’re required in larger weight amounts than
the remaining essential elements your plants need. Those are called micronutrients,
and they’re very important even though your plants don’t need as much of them. We’re
talking about iron, zinc, copper, molybdenum, boron, manganese, cobalt, and chlorine.
Until recently, silicon wasn’t even included in the essential element list, but modern
research on marijuana plants indicates your plants use silicon to build strong cell walls,
resist pests and diseases, and to create THC glands.
Nutrients problems most likely to reduce growth rate, THC percentages, and harvest
weight often involve nitrogen, phosphorus, potassium, and calcium. But problems with
deficiency or excess of any of the 18 essential elements is likely to cause serious
trouble for your marijuana plants.
How do you know your marijuana plants have nutrient deficiency or excess? Look at your leaves.
If they’re not lime green, upright, and looking like the perfect marijuana leaf photo
accompanying this article, your leaves are trying to tell you something.
But here’s a twist…it may not be your organic fertilizers, soil, or hydroponics nutrients
that are actually causing the problem. Signs of nutrient element shortages or excess may
merely be a symptom of the real cause of the problem. For example, low temperatures
interfere with nutrient uptake. So you can’t solve a temperature-related nutrient
deficiency problem by increasing your nutrients dosing…you solve the temperature
problem instead, so your marijuana plants can take in what they need.
The Right Amount of Nitrogen
Makes Your Marijuana Healthy and Green
Nitrogen makes up 78% of the dry volume of our atmosphere and plants need to
capture it if they want to grow at all.
No doubt you already know nitrogen is the big N in the N-P-K on your hydroponics
nutrients bottles, and it’s a big, important ingredient for your marijuana growing success.
Unless your plants are in the final weeks of flowering phase, yellow leaves
(especially lower leaves) are signs of trouble, and the troubles are most often
a nitrogen deficiency. It starts with the bottom leaves and works its way up until only
the newest growth is green.
On the other hand, if your marijuana plants are overdosing on nitrogen,
the leaves will be extremely dark green.
Either way, nitrogen problems mean big trouble for your marijuana plants because nitrogen is
absolutely necessary for plant survival because nitrogen is a primary elemental support for
protein synthesis, growth, leaf development, metabolism, and root health.
If you oversupply nitrogen, you get marijuana plants that are too tall, thin, and gangly.
It’s harder to get successful flowering from plants that have been overfed nitrogen.
If you see that the very tips of your leaves are yellow, that’s an almost sure sign of nitrogen
deficiency, which occurs most often during a fast-moving grow phase or when you’ve switched
to an improperly-configured bloom fertilizer during flowering. Many brands of hydroponics
nutrients do not contain the right ratios of nitrogen, phosphorus, and potassium, or they
contain the elements in forms that are not easily available to your marijuana plants.
These potential nutrients problems are especially harmful in flowering phase, when your plants
only have 12 hours to run their photosynthesis metabolism.
Nitrogen deficiencies first show up as leaf tip yellowing, especially on lower leaves.
Then it spreads to affect entire leaves, and moves up the plant. When you do research
on marijuana strains before you buy seeds or clones, take note of the strains that are
said to be heavy feeding. Those will likely want higher parts per million of nutrients,
and they are hogs for eating nitrogen, potassium, and phosphorus. In bloom phase, your
marijuana plants want less nitrogen, and more potassium and phosphorus.
The only time you tolerate signs of nitrogen deficiency is when you’re more than halfway
through flowering phase. During those closing weeks, your marijuana plants are focusing on
floral production so they sucks stored nitrogen out of leaves rather than doing the work of
That’s why you don’t need to add extra nitrogen (beyond the amount found in a properly-configured
flowering base nutrients product) to flowering crops after they’ve passed the midway point of
flowering cycle: excess nitrogen during flowering negatively affects bud development, taste, and aroma.
Fixing Nutrients Problems to Save Your Marijuana Plants
In later articles in this series, you’ll see a more detailed program for analyzing and fixing
marijuana nutrients problems but it’s important to understand a couple of things right away.
One thing to know is that organic or “natural” fertilizers often fail to remediate a deficiency
fast enough because they aren’t immediately bioavailable to your marijuana plants.
If you’re absolutely sure your marijuana root zone pH, grow environment, water, and other factors
are what they should be, and your plants are still showing signs of nitrogen deficiency in soilless
hydroponics marijuana growing, it almost has to be that something’s wrong with your base nutrients.
What are your remedies? If you’re growing in soilless hydroponics using synthetic hydroponics
nutrients, you have it pretty easy.
First, make sure your pH meter is working perfectly (or use the new pH Perfect base nutrients
that automatically buffer and adjust pH to the ideal sweet spot). Flush your
plants (I prefer
Final Phase or Flora Kleen), dump your reservoir, fill with reverse osmosis
water, and feed with
quality hydroponics base nutrients. When I say “quality hydroponics
nutrients,” I mean a reliable
brand of hydroponics base nutrients other than the brand you were using when
the nutrients deficiency
You can also experiment with slight up and down adjustments of nutrients
strength (ppm) or nutrients
water pH and see if that corrects the problems. For example, many of us
follow the dosage instructions
on nutrients bottles and end up with 500+ ppm during flowering. In some cases,
that’s too much, and what’s
really strange is that using too much nutrients can result in nutrient deficiencies.
So try changing your dosage 50-100 ppm in either direction, and see if it makes a
Try adjusting you pH from 6.2 to 6.0. Different nutrients interact with root zone
water differently, so that you might get absorption of 12 elements, but the pH is
wrong for three
other ones. Even small adjustments in pH (unless you’re using pH Perfect base
nutrients in which
case it doesn’t matter), can affect individual element’s absorption.
Reply from fellow grower:
After closer inspection, yes, SPIDER MITES crawling on underside of leaves. They disappeared 1/2 hr later.
I’m spraying wi 90% water and 10% vinegar. Any suggestions?
The spider mites disappeared after you discovered them??? Sounds strange
Hope you get them under control.
These are spider mites and they don’t go away. I do see some black/dark spots on leaves in first pic but bulk of looks like as @garrigan65 stated white powdery mildew. Best of luck
Spider Mites don’t just disappear my friend and those black spots look just like their poop they leave behind and are those buds have a web on them because it sure looks like it from the pic’s you posted. I can’t blow the pic’s up for a better look. Well I just saved the pic of the three cola’s and you sure do have spider mites. The cola’s are covered with spider web’s.
You can kill these critters with alcohol and water. It will kill them on contact. And it drys real quick leaving no Resido.
Use 25% alcohol to 75% water 0r 50/50
But you better get on it or it will be to late if it isn’t already
Thank you for the eye @garrigan65. Like the quick dry of the alcohol. Will do tonite when I get home from work. Thank you for the alternate method. Been using 3 % peroxide without much success.
Peace for now. Help is always appreciated.
I had spider mites and there no fun what i did was used water and a few drops of dawn dish soap and sprayed them every day for a week and it work for me bow every few weeks i give all my plant a light spray and havent had a problem sent i started doing it nit say u should do it just a nother option for u but every one on here has help me out when i have troubled
@ronnie_miller. I sprayed with 35%alcohol solution and then turned on the fans. 3 under screen. I will redo the alc tonite to make sure I didn’t miss any. I thank you for the help I have found everyone here is out for one thing and that is to grow the best possible meds.
Everybody so willing to help is wicked.
I think it’s great that so many are willing to help. If I don’t see a diff in a few days I will give the soap solution a go. They’re getting pretty ragged between the mites and defoliation and treatments.
Hopefully I can still salvage a bit of smoke from this one to tide me over till next is done. Lots of improvements coming before I replant another.
Peace for now. Thanks.
And remember to spray the bottom of the leaves that where u will see the spider mites they live on the under side of the leaves
Knew that . Thanks.
K did no if any one sead anything to u about that