Hi, from some reason I can’t start new topic so I’m writing here hoping someone would read it. I have a problem with my plant and I don’t know how to react, I suspect that it is leaf septoria but also hopes that it is only manganese deficiency. I found 1 white spot on a leaf 48h ago and now i have 3/4 of them and bigger. ~24h ago I added more bio nutrients hoping it will cure deficiency but since then nothing changed. @garrigan62 you are advanced pro, do you have any suspects?
This was taken few hours after i noticed it:
This one was taken 48 hours after first one
The other side of plant
The whole thing
It’s probably not a deficiency but a PH issue, what is your PH going in?
I have the tester on my spot so i can check it tomorrow. @Aolelon
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Yellow leaf spot, also known as leaf septoria, are caused by Septoria cannabis and S. neocannabina. These are fungal pathogens aimed specifically at marijuana plants.
It is brought about by warm weather and rain and effect marijuana grown outdoors. It may also show up in nitrogen- deficient plants. Read this article and learn how to identify and treat yellow leaf spot.
Signs of leaf septoria
Signs of leaf septoria weed
Yellow leaf spot initially shows up on the lower leaves of your plant. These spots may vary in shade from white to a grayish brown to yellow, initially displaying little circular lesions. Once it starts to grow it starts looking like a bump and its size continues to increase.
Yellow leaf spot will harm the leaves and often times the stems of the plant, although it won’t cause the crop to die off. If for any reason this is not properly cared for it will lessen the marijuana plants yield. The affected leaves will become dry where the spot is and overtime break and produce a hole at the point where the spot started off.
Not sure if your marijuana plants suffer from a yellow leaf spot infection? Check the article Marijuana diseases for a list with pictures of all possible marijuana diseases
How to avoid and cure leaf septoria
Cure yellow leaf spot cannabis
The most affected leaves will become totally yellow, dry out and fall off. You will want to get rid of the leaves that fell off or else you will end up with a landing turf for spores to overwinter. Basically, they will hide out until the weather warms up and then that’s when they will wreak havoc. Yellow leaf spot spores do their dirty work through traveling by water, wind and clinging on to things that pass by.
You can avoid the damage yellow leaf spot causes your plants through crop rotation. Basically, after every harvest you will pick a new location to plant. If you are not able to do this, then after harvest, completely get rid of all leftovers from the last vegetation and till the soil really good to make sure all remains are gone.
Download my free marijuana grow guide at this link for more growing tips
Get the location ready using sterilized compost and mix it well into the soil. Doing this will give the new crop plenty of nitrogen to provide a good, strong start. If you don’t have any ready compost, you can mix in blood meal, fish meal or soybean meal to the dirt that is already there.
Therefore, you will be certain to have all the necessary nitrogen for your plant. Make sure you proper disinfect any tools you used with rubbing alcohol or peroxide prior to putting them away.
One more thing you can try when beginning a new marijuana bed is adding a fungicide to the planting location prior to putting the seedlings and seeds there. You have the option to buy one of the many natural solutions pre-made (at this link here) or you can make your own.
Applying helpful bacteria, like Bacillus Pumilis or a good fungi like Trichoderma will help the soil if you don’t have any compost to use. Also, you may try spraying the site with essential oil combinations with cinnamon, coriander, neem, sesame or clove. Fine misting the soil with compost tea or even baking soda will aid in avoiding yellow leaf spot spores from making a home at your site.
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Marijuana plant symptoms
– white/grayish brown/yellow spots on leaves
– Circular lesions on lower leaves
– A small pimple looking bump
– Leaves dry and fall off
Remember to water your plants early mornings or early evening time. Never water the leaves, only the soil. By doing this, the sunlight will not burn the leaves. Again, if your plants gets infected by yellow leaf spot, it is important to always remove and completely destroy all affected leaves.
If you don’t do this, you will most likely regret it. Affected leaves still contain the problem and can come back to haunt you because yellow leaf spot easily clings on to things and travels from one destination to the next.
Remember that plants with strong genetics have less change of getting sick and are less vulnerable for pests and diseases. So make sure to buy cannabis seeds from a trusted seed bank.
Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible
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Learn the basics of growing marijuana and get started today
How to get the biggest yields from cannabis plants.
Writen by Robert B.
Posted by garrigan62
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I already read it on guide version of ILGM site but still I’m not sure is it leaf septoria or not. On pictures it looks a bit diffrent and you didn’t say anything about your opinion. I would really appreciate if someone could tell what it is using his expierience (i don’t have any).
Have you checked your leafs with a Magnifying glass ?
If not please check and see if you have any critters on them. You can’t tell just by looking at them.
But this is from my own personal experience hopefully you won’t be surprised by what you may or may not see. But please check and let me know.
Will
Thank you @garrigan62. Much appreciated.
Sorry for not responding for so long, the spots stopped growing, and plant looked healthy but today morning i found one small spot on a new leaf and i was frustrated, it is possible that it is Ph problem which still i didn’t checked 
I have to do it necessarily but I can tomorrow near 12:00 so, if my Ph is bad what should i do to change it? (i don’t have Ph-up Ph-down liquids and i can’t get them 
If you check it as you say you will.
I’ll help you with that using what you most likely have in your home
Will
awsome! I’m on my way so i’ll have results within 3-4 hours
@garrigan62 I checked Ph levels twice, and you were right, it has catastrophic ~8,0 . My water changed from 6,0 to 7,0-7,5 in just 2 weeks, please help me, how to undo what i have done?
Your going to have to do this…
One of the common problems that most growers face is alteration in pH levels in the soil, which can occur for a number of reasons. For instance, over fertilizing will no doubt create a pH imbalance in any type of soil used to grow plants. Organic soil additives tend to raise pH levels when used incorrectly while synthetic fertilizers may cause salinity, but effects vary depending on the actual chemical composition of fertilizers used. Purified water is also a major contributing factor that interferes with normal soil pH and especially tap water treated with chlorine.
You can tell that there is something wrong with the soil in which marijuana plants are growing when certain abnormities start to occur despite giving your plants adequate water, proper nutrients and lighting. When the pH level of soil is tampered with, a lot of problems can occur. For starters, older leaves start to curl and may also develop tiny yellow, brown or red spots. As the soil pH problem continues, these spots can start to appear anywhere on marijuana plants including the stalk. pH imbalance that is ignored goes on to cause nutrient intake problems by blocking out essential minerals for your plants. In fact, unsuitable soil pH is one of the causes of mineral deficiency disorders in cannabis plants.
It is easy to confuse mineral deficiency with pH imbalance when caring for cannabis plants because these two cultivation problems present almost similar traits. However, problems with pH levels are evident when fertile soil has been chosen for cultivating cannabis crops or when you have been following a proper nutrient feeding regimen.
The first step towards fixing soil pH is to test your water and soil. Water that has impurities may have a slightly altered pH, but a good reading should be close to 7. If the problem is caused by the water you are using to feed your plants, then you might want to consider changing to a different source of water. On the other hand, you can use a digital pH tester to demine the level of acidity or alkalinity in the soil. When the pH is too high, it can be adjusted in a variety of ways such as adding sawdust, lemon juice, wood chips, peat moss, composted leaves and leaf mold. Alternatively, addition of wood ash, potassium hydroxide, lime, bone meal or crushed marbles can help to adjust pH that is too high.
It is imperative to treat the soil gradually for up to a week before attempting o fix any mineral deficiency problems that you may suspect. Sometimes mineral intake or lack thereof may stem from pH imbalance in soil that is rich with all the essential nutrients that marijuana plants require.
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Thanks a lot! I’m starting to cure it, i will let you know how am i doing 