Knowing things like the following, or at least as many of them as possible, are always helpful when questions are asked.
ARE YOU USING?
SOIL:
How long has this problem been going on?
What STRAIN are you growing?
Who is the breeder of the strain?
What was the establishing technique? (seed or clone?)
What is the age of your plants?
How long have they been in the soil mixture they are in now?
Were they in the same mixture when they were seedlings/smaller plant? If not, what mixture were they in before?
How Tall are the plants?
What PHASE (seedling, vegetative or flower) are the plants in and how long into either?
What Technique are you using? (SOG, SCROG etc)
What size pots are you using? (Include how many subjects to pot)
What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?)
What brand Nutrient's are you using?
How much of each nutrient are you using with how much water? *Knowing the brand is very helpful*
How often are you feeding?
If flowering, when did you switch over to using Bloom nutrients?
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect)
What is the TDS/EC/PPM of your nutrients used?
What is the pH of the "RUN-OFF"?
How often are you testing pH/ppm/EC/TDS?
What method of pH test was administered? Using Strips? pH pen?
How often are you watering?
When was your last feeding and how often are you feeding?
What size bulb are you using?
How old is your bulbs?
What type of bulb, MH/HSP/CFL/LED or some combination?
What is the distance to the canopy?
What is your RH Factor? (Relative Humidity)
What is the canopy temperature?
What is the Day/Night Temp? (Include fluctuation range)
What is the current Air Flow? (cfm etc.)
Tell us about your ventilation, intake exhaust and when its running and not running ?
Is the fan blowing directly at plants?
Is the grow substrate constantly wet or moist?
Is your water HARD or SOFT?
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
If using tap water, what is the ppm/EC/TDS of the water right out of the tap?(Only if you have a tds pen)
If using RO,Distilled,mineral water, what is the ppm/EC/TDS without any additives?(Only if you have a tds pen)
Are you using water from a water softener?
Has plant been recently pruned, cloned or pinched?
Have any pest chemicals been used? If so what and when?
Are plant's infected with pest's?
HYDROPONICS/Aero Ponics/Coco/Soiless/
How long has this problem been going on?
Are you growing in a PVC grow tent? (example: Hydrohut or any other non brand tents)
What system are you running? (DWC? Ebb flow? Aero? Water Farm? Flood Tables? and so on...)
What STRAIN are you growing?
Who is the breeder of the strain?
What was the establishing technique? (Were the seed or clone?)
What is the age of your plants?
How long have they been in there mixture they are in now?(coco,soiless etc..)
How tall are the plants?
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in and how long have they been in either?
What Technique are you using?
What substrate/medium are you using?(Hydroton, RockWool etc.)
What is the Water temperature?
What color are your roots? White? Brown? Are your roots slimy?
What Nutrient's are you using?(If growing soiless)
How much of each nutrient are you using with how much water? *Knowing the brand is very helpful*
How often are you feeding? (If using soiless)
How often are you giving nutrients? (If using soiless)
If flowering, when did you switch over to using Bloom nutrients?
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect)
What is the TDS/EC/PPM you are using
What is the pH of the "Tank"?
How often are you testing your pH/PPM/EC/TDS?
Are you sure your calibration is correct on your equipment?
When was your last watering?
What is your water temps?
When was your last feeding change? (ie. grow-bloom-micro-additional)
How often do you clean your system: example: Flush out water replace with clean water and nutrients?
What size bulb are you using?
What type of bulb are you using, MH/HPS/CFL/LED or some combination?
How old is the bulbs you are using?
What is the distance to the canopy?
What is your RH Factor(Relative Humidity)?
What is the canopy temperature?
What is the Day/Night Temp? (Include flucutaion range)
What is the current Air Flow? (cfm etc.)
Tell us about your ventilation, intake exhaust and when its running and not running ?
Is the fan blowing directly at plants?
Is your water HARD or SOFT?
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
If using tap water, what is the ppm/EC/TDS of the water right out of the tap?
If using RO,Distilled,mineral water, what is the ppm/EC/TDS without any additives?
Are you using water from a water softener?
Has plant been recently pruned, cloned off of or pinched
Have any pest chemicals been used? If so, What and When?
Are plant's infected with pest's