Nutrient stress in addition to slight light burn?

[alpinebuds]

Hi guys and girls, I've been lurking for a while and decided to ask for a little help with my babies. They're in week 4 of flowering with beautiful bud sites frosting up, which is particularly fun to watch as this is my first ever grow. I am very confident that a low hanging lamp gave them a little light burn but don't know what to think of my other problem. Leaves all over the plant are yellowing, rolling upwards and dying with necrotic brown spots. I'm leaning towards a nitrogen deficiency, but then what the hell do I know? Hoping to get some hints from more seasoned growers and thanks for reading this in the first place.

[FONT=Arial, Helvetica, sans-serif]How long has this problem been going on? for about two weeks
What STRAIN are you growing? Sensi Seeds' "Big Bud"
What was the establishing technique? (seed or clone?) clone
What is the age of your plants? they're in their fourth week of flowering as of now
How long have they been in the soil mixture they are in now? since the beginning
Were they in the same mixture when they were seedlings/smaller plant? If not, what mixture were they in before? do not know
How Tall are the plants?
What PHASE (seedling, vegetative or flower) are the plants in? flower
What Technique are you using? (SOG, SCROG etc) none
What size pots are you using? (Include how many subjects to pot) 7 liter pots
What substrate/medium are you using? soil
What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?) 20% perlite
What brand Nutrient's are you using? Hesi
How much of each nutrient are you using with how much water? Hesi Bloom and Hesi Phosphorus as indicated by Hesi every few waterings
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) ph the water first, then bloom, then phosphorus plus
What is the TDS/EC/PPM of your nutrients used? dont know
What is the pH of the "RUN-OFF"? 6.5-6.7
How often are you testing pH/ppm/EC/TDS? every watering
What method of pH test was administered? Using Strips? pH pen? ph pen
How often are you watering? when the soil is visibly dry
What size bulb are you using? HPS 600W
How old is your bulbs? new
What is the distance to the canopy? 50 cm
What is your RH Factor? (Relative Humidity) 40%
What is the canopy temperature? 27° C
What is the Day/Night Temp? (Include fluctuation range) 19°-27° C
What is the current Air Flow? (cfm etc.) 400 cfm/800m³/h
Tell us about your ventilation, intake exhaust and when its running and not running ? only intake, always running
Is the fan blowing directly at plants? no
Is the grow substrate constantly wet or moist? no
Is your water HARD or SOFT? tap water with about 8.0 pH before adjustment

I am attaching pictures which should provide a good view of what is going on.

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[alpinebuds]

Sorry for the wall of cra*, don't know what happened there.

 

[MJINC]

Are the yellowing leaves falling off or are they easy to tug off? Also do they tend to be lower down the plant? If so more then likely it's nitrogen deficiency.

 

[alpinebuds]

Are the yellowing leaves falling off or are they easy to tug off? Also do they tend to be lower down the plant? If so more then likely it's nitrogen deficiency.

They are very easy to tug off indeed, all with purple-reddish stems. I can see that after initially starting on the bottom third of the plant, the yellowing has moved on to the top leaves. Should I supplement with Nitrogen, seeing as how there is still about a month of flowering to go?

 

[raphenilweed]

pH after adding nutrients, air exchange is poor, switch intake to outtake. nitrogen deficient. clean up those lower parts better next time

 

[alpinebuds]

Thanks for the replies guys! I'm now 99% sure on a nitrogen deficiency, I believe they didn't have enough in the first two weeks of flowering.

 

[Westbrook0112]

When did you start giving phosphorus? Mine are 3 weeks into flowering outdoor and I still havent add any phosphorus.. also using hesi and its my first ever grow
I was about to start giving phosphorus in my next feeding. Buds look like this right now..they still need a month to completely finish off approximately according to breeder.. top buds look like ready but lower buds not as nearly as top ones… thoughts?

 

[Creeperpark]

Using a 600 watt, you are flowering in too small of a container. Plus with the addition of 20% perlite, to the soil, it has made the mix limited.

 

[Ca++]

What soil

I don't see N deficiency foremost. I see Mg. The colour is leaving in the pattern of Mg and the leaf eventually turns a bright yellow, not weak yellow. There is also a lot of water about.

 

[Creeperpark]

Post a photo showing the whole plant in the container please for the best help. It's hard guessing from looking at a leaf.