5 weeks into flowering leaves quickly become yellow and burn.

[GrowHardOrGrowHome]

I thought it was a manganese deficiency at first but now I suspect a root problem.
I have no idea though, I have had problems with this plant since 5 weeks into veg.

One week ago

Today

1. Are you growing from seed or clones?
Seed
2. How old are your plants?
10-17 weeks, 5 weeks in flower
3. How tall are your plants?
About 55 cm
4. What size containers are they planted in?
4 gallon container
5. What is your soil mix?
85% soil 15% perlite
6. How often do you water and what type of water do you use?
3 to 4 times a week, regular tap water from Netherlands.
7. What is the pH of your water?
With nutes 6.3 to 6.7 without around 7.5
8. What kind of fertilizer do you use and what is its NPK ratio?
HYPRO TERRA 2-5-5
9. Do you foliar feed or spray your plants with anything?
No
10. What kind of lights do you use and how many watts combined? (HPS, MH, fluorescent, halogen, incandescent "plant lights")
LED maxisun 100 watts
11. How close are your lights to the plants?
12 inches
12. What size is your grow space in square feet?
4 square feet.
13. What is the temperature and humidity in your grow space?
At day around 20-22 degrees celcius at night 17-18, has dropped below 15 a couple off nights but this has been corrected.
14. What is the pH of the soil?
after watering around 6 but goes to 7 when drying.
15. Have you noticed any insect activity in your grow space?
Fungus gnats but populations are well under control
16. How much experience do you have growing?
I have grown before but am no exper.

Strain: fat banana
Age: 5 weeks/35 days into flowering
Problems: yellow leaves that curl up and burn

I have had problems with this plant for a long time during veg and flowering,
Currently leaves are quickly yellowing after which they heavily burn and brown.

LIGHTS:
100watt led panel placed 12 inches away from top.
I thought it might be light stress however many fan leaves that are far away from the light source and under the canopy are also affected in the same way.


TEMPERATURE:
Plant might have had a few colder nights going as low as 14 degrees celcius at night but this has now been solved while problems continue, adjusting the temperature has not slown down progression off problems.

HUMIDITY:
Between 55 and 65%

HISTORY:
Plant has shown problems on and off during most off the grow but only now are problems progressing very quickly likely as a result off the growing buds.
Problems before where all over the board but could be managed:
Curling leaves, brown edges, light green colored leaves on top with spotting, I never figured out what caused the problems and new growth outpaced affected leaves.
Now problems are limited to yellowing leaves which become burned.
Overall growth seemingly has always been good, plant progressed really well, bud formation also seems to remain well, I don't feel that bud formation has slowed because off this but I do worry that it may if this continues much longer.

PESTS:
Some fungus gnats but is well under control.

Ph:
Is between 6 and 7 depending on the moisture level, usually around 6 after watering.

Air circulation:
There is a small oscillating fan running below the canopy that I have always used with good results.

Soil moisture:
I only water when the soil is dry, usually every other day with 2 litres.
What I am seeing now however is that my soil meter shows that moisture is going down slower.
NOTE: LAST NIGHT THE MOISTURE METER WENT UP NOT DOWN OVERNIGHT WITHOUT WATERING.
I have never seen this, does anyone know what this could possibly mean?

Fertilizers:
- I have fed a 2-5-5 solution from HYPRO TERRA 3 to 5ml per 2 litres.
- half a teaspoon molasses 1-2 times a week.
- I have fed calmag from bac at reccomended dosage a few times but does not seem to help.
- I am currently giving Rhizotonic from canna at reccomended dose 4ml/litre hoping it helps the plant with recovering from stress and to help with possible root issues.

OTHER NOTES:
This is not my first grow but this is the most confusing plant I have ever had by far, usually my plants are not hit by long standing deficiencies.
But with this plant signs off deficiencies seem to be all over the board then seemingly don't progress only to come back a week later.
I personally suspect it's a root problem but it's just a hunch since I don't see how it could be anything else, since I am 99% sure it is not a PH, light or watering problem as these are things that I have always monitored well for any grow, but I am open to listen to all suggestions.
I don't exclude the possibility off a common nutrient deficiency or toxicity while I feel that I have fed the plant adequately till now I obviously messed up somewhere big.

 

[GrowHardOrGrowHome]

By the way, first post hi.
I hope to learn lots from you wise masters on this forum.

 

[PipeCarver]

By the way, first post hi.
I hope to learn lots from you wise masters on this forum.

Hi, welcome to the forum. I expect some yellowing on the lower leaves as fall approaches, 5 weeks is getting there, Some strains more than others will do that and if you were hard on her at some point in flower the leaves take a hit and show later on.

For instance if I let my girls dry out to the point of hanging and even though with watering they popped back up some start turning yellow shortly afterwards and die off early in flower.
Maybe you were a bit low on food going into flower with her next time you grow it you'll know to up the food some before flowering.

Not to worry with a leaf or 2 here and there, low light, age, knocks and minor damage can do it to them.......If it all goes yellow there's more of an issue

She's pretty bushy you should be taking those leaves off anyways

 

[jesterthejedi]

Here's my take. I think your soil PH is too high, perhaps a slurry test will confirm. I saw a post on here about a citric acid way to lower your PH, I'll link it below. The reason: I think it's PH lock out because your plant isn't drinking or transpiring. Older leaves are also less efficient at transpiration. I say you should consider doing a defoliation. This will clear away the dead and inefficient older leaves and improve air flow. So that's would I do, first test the soil, then decide if you need to correct the PH, then clear out some leaves. I'd also check how soggy or dry the soil is and double check you have proper drainage.

Link