lower leaves turning purple-brown

[monkey_man]

hello all!

i have 2 plants, both are at the begining of their 5th week of flowering.
about two weeks ago i've noticed that in one of the plants, some of the lower fan leaves were starting to turn purple-brown, 3-4 days later it also happened with the other plant. since than, the color spread to some more leaves, but only to the lower/med sections and only to the larger leaves (not to the small ones which surround the flowreing areas).
in one plant, two of the purple-brown leaves developed large black spots (necrosis?), while all the other colored leaves appear fine if you check their buttom side (the black spotts were visible from both sides). the temperature don't drop below 60 F and is usualy above 70 F.
it seems that the discoloration has less effect on the veins of the leaves, as they are the last part to change color.
i searches a lot about this problem and did not found anything that looked similar.
disscussing this situation with a growshop salesman he adviced me to flush the plants as he think this is some sort of nut block - specificaly since i described my watering routine as one in which i water just untill the liquid start to come out beneath the pot and usualy not even that (all stays in the soil).
also, during the last days i notices the tips of the top leaves turning yellow (i guess it's a different problem)
i did not flush them yet, and would love to hear your advice - is there a problem? if so what is it? and what should i do?

pics and troubleshooting info below

thanks!



What is your experience level? 2nd timer
Your Equipment:
.1) Type and wattage of lights. HPS 400w
.2) Distance from tops? about 15 inch
.3) Reflector type? cool tube set-up
.4) Is there a consistent fresh air supply? now there is, untill 3 days ago i only opened the bellows while the light was on
.5) Do you have an exhaust fan and a circulation fan? i belive it's called a bellows, the device that sucks air out, no fans
.6) What are the bulb wattages, kelvin ratings, and schedule? 400 watts, 12/12

Your medium:
.7) Specific brand and type of soil, (coco, peat based soilless...) and anything you've added to it. (vermiculite, perlite, worm castings...) light soil, no addings
.8) Size of container. about 1.5 gallons
.9) Did you use peat pucks (or similar) to root clones or germinate seedlings? no

Your nutrients and water:
10) Source of water? (tap, bottled or filtered) What's it's ph before adjusting? bottled mineral water, pH of 7.8 before adjusting
11) Method of checking water ph. (ph pen, test strips, aquarium test kit...) test strips
12) Method of adjusting water ph. (phosphoric acid, white vinegar, hydrated lime, PH Up...) pH down
13) Specific brand and N-P-K ratio for each bottle. List dosages (quantity per gallon) and current feeding schedule. i use bio-bizz organic plant food, like 6 differnet bottles, following the instructions - note that the bottles are 3 years old, but smells fine. at the begining i watered every 3 days and in the last couple of weeks i water every two days
14) How often are you watering between feedings, and how much per watering? isn't watering and feeding the same? i give the plants water with food inside every second day now, about 0.4 liter for each plant
15) Any additives or tea's? (Superthrive, CalMag, molasses, Mother's Earth...) only the biobizz variety
16) Are your ph levels stable, or do they fluctuate? i cant tell as i can only check pH before i add the food
17) What is your ingoing water's ph? ...your runoff ph? idk
18) Do you foliar feed? If so, with what, how often, and at what time do you spray? no

Your growroom:
19) Indoors or outdoors? indoors
20) What size of closet, room or hut? 2x3x7 (in feets)
21) What are the temps and humidity levels while lights are on? ...With lights off? on - 60% 73-85 F. off - 65-70 F
22) Have you seen signs of insects in the growroom? no

Your strain:
23) What strain are you growing? (Indica dominate or Sativa dom?) not sure, probably indica dominant
24) From seeds or clones? seeds
25) Is this an autoflower strain? i guess not

monkey_man Reviewed by monkey_man on 03-23-2011. lower leaves turning purple-brown hello all! i have 2 plants, both are at the begining of their 5th week of flowering. about two weeks ago i've noticed that in one of the plants, some of the lower fan leaves were starting to turn purple-brown, 3-4 days later it also happened with the other plant. since than, the color spread to some more leaves, but only to the lower/med sections and only to the larger leaves (not to the small ones which surround the flowreing areas). in one plant, two of the purple-brown leaves developed Rating: 5

[Charbud]

I wouldnt worry about the purpleness. happened to my bubble cheese like mid flower and it was fine, only thing was the leaves didnt go brown ? Id check that ingoing ig between 6.3 - 6.8, check run off and if theres any inconsistancies give her a good flush with adjusted water.

[monkey_man]

thx charbud, i hope youre right...

[TANKJR]

Sounds like a good flushing is in order...I agree with Charbud...

The fan leaves are gonna start dying and falling off from here on out anyway...

[CanGroIt]

" isn't watering and feeding the same? i give the plants water with food inside every second day now, about 0.4 liter for each plant "

monkeyman - watering and feeding are two entirely different things, depends on who you ask. It looks like you have a serious case of nute burn or over fertilization. Please flush them....... To avoid this in the future make sure you give plain Ph adjusted water every third or fourth feeding/watering. Personally I nute nute water and flush on week 5 of FL and just before harvest. Reason why I flush on week 5 of flower is because I plan on giving extra strength K on weeks 6 and 7. Just my 2 cents......

Happy Growing......

[monkey_man]

thanks guys!

so, just to make sure we're on the same page here: it's now 2.5 days after the last feeding and the girls are just about to go to sleep and looks ok, i trimed the dead leaf and no new dead spots have developed. 12 hours from now im going to flush them with adjusted water, im thinking of giving them 1.5 Liters each. also, the growshop person told me that when i flush i should add the regular amount of "alg-a-mic" - any comments on that?. also, i mistakenly wrote that i use pH strips - i actualy dont have them, what i do is to adjust pH with the pH kit where i put 3 drops of the tester in a vial half full of water and then compare the color to a chart - so i can't realy use this method to tell the ph of the runouts, or the water once i added the nutrients, i guess i should get me some strips...
then, according to some views, i should start giving regular amounts (lets say 0.5 liters) of clear and adjusted water, instead of every 3rd/4th feeding.

is that correct?

p.s. it's now been 9 weeks since i last got high, which is by far the longest period of clarity i had since i started getting high, that is - in 11 years. 7 more weeks to go...

[seventhchild]

spend $25 on a PH meter and save yourself from many headaches in the future ....Milwaukee PH 600 Digital pH Meter/Tester/Pocket/Pen New - eBay (item 250311642470 end time Apr-07-11 12:03:29 PDT)

[WashougalWonder]

You have a lockout going on. This is causing a deficiency which is showing up as the purple. The previous advice of flush is the way to go, and ease up on nutes or flush more frequently. You probably only have about 3 weeks to go from the looks of things, expect the sun leaves from the bottom up to start turning to a yellow, getting dead spots, dying and many other appearances. The purple you see is indicative of a nute deficiency, which is caused by too much of one nute blocking the plants ability to uptake the needed nutrients. One needs to remember what we learned in high school about osmolarity and permeable membranes. All life needs a certain range of salts (Nutes to us) to exist without illness. These must be in balance to work properly.

[monkey_man]

ok ok,

so i just flushed them both, with 1.5 Liters each of water + 3ml/L of algamic.
in going pH was about 6.6, run off i collected 700cc each and the pH was about 6.9
so... does that mean im slightly up on the base side?
should i do anythinh special now?the pots took about double the liquid amount they usually take - so my plan is to return to regular feeding in about 3-4 days, should i redo the 7th week again or continue to the 8th week? also, i usualy make a weekly amout of food and use it throughout the week - but i read somewhere here that better not to let the organic food sit and wait, should i take that seriously and prepper a mix for each feed seperatly? or just keep it in the dark?

thanks guys you are the best!

[Charbud]

ok ok,

so i just flushed them both, with 1.5 Liters each of water + 3ml/L of algamic.
in going pH was about 6.6, run off i collected 700cc each and the pH was about 6.9
so... does that mean im slightly up on the base side?
should i do anythinh special now?the pots took about double the liquid amount they usually take - so my plan is to return to regular feeding in about 3-4 days, should i redo the 7th week again or continue to the 8th week? also, i usualy make a weekly amout of food and use it throughout the week - but i read somewhere here that better not to let the organic food sit and wait, should i take that seriously and prepper a mix for each feed seperatly? or just keep it in the dark?

thanks guys you are the best!

Ph sounds right to me, could take it down to 6.4 or 6.5 to be picky. If your in your 8th week id stick with giving them plain water and make sure there properly flushed for when you harvest. You dont want any nasties left in your bud before you smoke it. They probably wouldnt get much bigger anyway, in my opinion most growth is from weeks 3 - 7. Then the rest is when the trichs start to mature and they get a lil bit bigger.