Help with nutrient burn - 1st time grower seeks advice

[Ar Mayer]

Hello, I'm on my first grow and could really use some advice.

Background: I'm currently day 28 from seed, growing white widow & early miss auto-flower strains (Crop King Seeds) with Gold Label bagged coco coir and could use some guidance, as I have run into trouble. My grow tent stays between 22-26C, with a RH of 50-75% throughout the day. Grow Light: Sun LEC 315W, Phillips 3100K.

Issue: I noticed yellow tips on both plants (see image 1564, taken today - white widow is on the left), and what I believe is nutrient burn 7 days ago (day 21 from seed). At that time, I was feeding twice daily using distilled or rain water @ 600PPM - Sensei PH Perfect Grow (2ml per ltr), Calimagic (1ml; per ltr), Voodoo juice (2ml per ltr), GH Rapid Start (1/4 ml per ltr) & Enzymes Komplete (1ml per ltr) - occasionally a low dosage of Superthrive, PH'd to 5.5-5.8 I checked PPM runoff and noted it was coming out around 1000 PPM.

My response: I rinsed the medium until I achieved run-off of 500-600 PPM, using multiple gallons of PH'd water @ 400 PPM (Grow, Calimagic - PH'd 5.8). I have since kept the feedings to twice daily (10-20% runoff each time) using a reduced solution of 450 PPM , PH'd: 5.8 - 6: Sensei PH Perfect Grow (1ml per ltr), Calimagic (1ml per ltr), GH Rapid Start (1/4 ml per ltr) & Enzymes Komplete (1ml per ltr) - but I am still getting yellow tips on new growth, even though PPM & PH runoff are staying within an acceptable range (400-500 PPM, PH: 7ish).

From what I have read, 450 PPM should be on the lower end of the scale at this point in the grow (day 28). Some I'm unsure as to what to do next. How long does nutrient burn last? I realize old growth is burned, but I expected new growth to have cleared up by now -- and the plants have grown significantly in the past week as well (as seen in the individual pics taken 8 days ago - images 1529 & 1535). Should I have flushed with plain PH'd water, instead of a reduced nutrient solution? Any guidance (from all growers) would be greatly appreciated, as I'm unsure as to what my next response should be. I was prob going to flush, or reduce to 300 PPM.

As an aside: I think the white widow is mag deficient - this has been going on for the entire grow - I started Calimagic @ day 14, but the discoloration has persisted. I'll be supplementing with Epsom salts starting tomorrow.

My apologies I have posted my questions in the wrong place (or thread).

Cheers,

AR Mayer

 

[Waira]

AM-- good info mate- First, I should ask if the ceramic metal halide light tends to make the leaves look more yellow than they really are? (COB light does this too)... Second, I'm not a coco experienced grower, but seeing all the problems that come in here with coco, has schooled me some! I have guru's to consult as well,... I'd say you've a solid handle on coco's quirks and unusual CEC properties,.. using that nute/Ca-Mg flush water was smart! (never use just plain water, it'll screw up the CEC buffering).... [HASHTAG]#1[/HASHTAG] problem I see is peep's treating coco same as true soil, or even soilless peat mixes,...
-- I see the odd color break on the WW, something we see fairly often it seems,.. to date, I have no explanation for it,... usually it corrects, though more rarely it carries though the whole grow, or disappears part way through,... no other growth distortions or stunting, so viral is very likely out (super rare, only way to know for sure are virus-specific tests)... it's not Mg defc., IMO either...

--- middle pic plant looks fine to me,...

--- the larger two, I do see the tip yellowing, but no newest growth distortion (usually N-tox' starting)... Odd, considering you're running on the low end of nute conc. ppm's, stranger still is your run-off coming out more alkaline than going in- no lime in there, right? run-off ppm is rather low too, I believe my mate said about 200ppm over inputs is OK,... The symtpoms are so mild, don't sweat it, stay at the conc. you're at, no lower or you may get other defc. issues starting.... if it's halted, I'd even start easing it up again... *( how old are your nutes? some can go bad, or foul out from cross contamination,... just a caution!) ... the enzymes, is that recommended to be used constantly like that? Hygrozyme does not,... point is, if the nute conc. isn't behind the tip yellowing, something else is wonky, however mildly,...

 

[Ar Mayer]

Waira, thank you so much for responding! To answer your questions. The nutes are newly purchased and not expired. Not sure what you meant by "lime", but I was using lemon juice to lower PH.

What I modified: Added Epsom Salt & BS-molasses (1/2 tsp per gallon). Foliar sprayed twice with Epsom salt. Changed from distilled water (PPM = 3), to a half-and-half mix of distilled and tap water of 140 PPM -- 70-80 PPM mixed. Raised the 3100K CMH light from 17 to 22 inches above the canopy. Cut out enzymes. Stopped using lemon juice to lower PH - replaced with PH down from local hydro shop. Kept nutrient solution at Grow (1ml per ltr). Total PPM: water + nutrients + additives = 550. PH = 6.0

Update: A few days later (day 30 from seed) and things seem to have turned around. The "yellow tips" are still there, but I have noticed the ladies seem happier and far more vibrant (see attached pics from this morning) and new growth is exploding and looking healthy. I have also LST the WW-Auto (left plant), as vertical height is a luxury for me on this grow (my tent is approx: 5 feet 5 inches) and I can't move the light up too much further (6 more inches maybe). The Early Miss I tried to LST, but it's too late -- the main cola's stock is far too thick and she has started pre-flowering already.

Thanks again!!!!

AM-- good info mate- First, I should ask if the ceramic metal halide light tends to make the leaves look more yellow than they really are? (COB light does this too)... Second, I'm not a coco experienced grower, but seeing all the problems that come in here with coco, has schooled me some! I have guru's to consult as well,... I'd say you've a solid handle on coco's quirks and unusual CEC properties,.. using that nute/Ca-Mg flush water was smart! (never use just plain water, it'll screw up the CEC buffering).... [HASHTAG]#1[/HASHTAG] problem I see is peep's treating coco same as true soil, or even soilless peat mixes,...
-- I see the odd color break on the WW, something we see fairly often it seems,.. to date, I have no explanation for it,... usually it corrects, though more rarely it carries though the whole grow, or disappears part way through,... no other growth distortions or stunting, so viral is very likely out (super rare, only way to know for sure are virus-specific tests)... it's not Mg defc., IMO either...

--- middle pic plant looks fine to me,...

--- the larger two, I do see the tip yellowing, but no newest growth distortion (usually N-tox' starting)... Odd, considering you're running on the low end of nute conc. ppm's, stranger still is your run-off coming out more alkaline than going in- no lime in there, right? run-off ppm is rather low too, I believe my mate said about 200ppm over inputs is OK,... The symtpoms are so mild, don't sweat it, stay at the conc. you're at, no lower or you may get other defc. issues starting.... if it's halted, I'd even start easing it up again... *( how old are your nutes? some can go bad, or foul out from cross contamination,... just a caution!) ... the enzymes, is that recommended to be used constantly like that? Hygrozyme does not,... point is, if the nute conc. isn't behind the tip yellowing, something else is wonky, however mildly,...

 

[Waira]

Better indeed! Nice job on the correction AM, I dig it
... enzymes are great, so keep using them ...just not every time,... are you using any microbe inoculants? The herd plays a very important role in break down and cycling, along with the enzymes,...
... by lime, I mean CaCO3 lime, Ag' lime, garden lime, dolomite, etc.,.. these have Ca and Mg in them, plus the carbonate ion plays the main role in pH buffering,...
.. I hear you on the lemon juice,.. seems it has little "staying" power,.. I found straight citric acid (canning type) is a nice alternative,.. the pH products are made from harsher chem's, phosphoric acid, hydroxides,...
.... damage won't reverse/repair, so it's a halting of progression you're looking for,.... ditto for new symptoms,..
... if it get bad in there with hieght, look into supercropping, a method that carefully bends the main stem until it folds/kinks over at 90degrees,.. it keeps the conductive tissues intact, even though it look like a disaster!