Sad Plant Problem

[grapenut]

Hello everyone this is one of my first grows here.

Things seem to have started off well but I have encountered a problem.

Strain: Critical Kush (Barneys Farm)

Grow Method: DWC

Nutrients: AN Sensi Grow and Bloom

Lighting: PlatinumLed P300

Location: Grow Tent with Inline Exhaust fan and carbon scrubber

So I started out by germinating my seed using the towel method then placing it in vermiculite until she generated a root system and cotyledon appeared. After that I rinsed off the vermiculite placed her in a neoprene collar and into my simple DWC system (Rubbermaid tote with air stone). After a few days I noticed she was growing but leaves had a slight yellow color so i added 8mL of part A and B sensi Grow to around the 2-2.5 gallons of water in the tote (around 1/5 strength, at a recommended 16mL per gallon).

She was doing amazing, incredibly green and vigorous growth. At around the 4th node I decided to do a reservoir change and up the nutrient strength to 24 mL (around 3/5 strength). This is when bad things begin happening, within a few hours the lowest fan leaf set had curled up and became crispy to the touch. I became worried and immediately thought of nutrient burn so I diluted my reservoir by half (replaced half of its water with fresh tap water. I also checked the pH using pH strips which indicated pH in the high 6 range, so I added a little lime juice to drop it back down to around 5.5-5.8. The next day I noticed that the complete set of lowest fan leaves were totally dried out and crumbling, so I removed them with a sterile blade.

The next largest fan leaves seemed to begin drying out, so I rinsed off the roots and did a complete flush for 2 days under which time I noticed no significant change in the plants appearance.

As of two days ago I added nutrients back again at the original 1/5 strength and today (3 days later) the current lowest set of fan leaves have turned almost completely yellow and the newest growths are beginning to show browning on the tips. So at the moment I did another flush and she's currently sitting in just plain tap water. What I have noticed is that she is rapidly growing new branch roots from the upper portion of the tap root and that the roots that are submerged are brown and seem very soft like wet string. The pH is around 6 at the moment and im not sure about what else to do. She is on a 24 hour light on cycle.

Root rot is an idea that came up, I have just currently added 2 mL of of Dutch Master gold zone to the reservoir.

 

[BuddroGreen]

Way to much nutrient for a plant that size. I use AN GMB (grow,micro,bloom) in DWC using water farms which I use 2.5 gallons in and don't go over 10-12ml/gallon each part when they are 3-4 feet tall and in 4-5th week of flower. I would let them flush for a few days with just pH adjusted water...maybe 3-5 days...get some hydro guard by Botanicare or another great product I have been testing that works in conjunction with beneficial bacteria/fungi is Flying Skull z7, use in reservoir and get that water temp down as cool as possible to 68-72f, and then bring your nutrient solution up to about 300-400 tds/ppm (around 5-6ml/gallon each part) total with just Sensi Grow A/B, no other supplements except mycorrhizae/bacteria's for your root issue. Once you see them starting to take off again, just slowly up your ml/gallon of Sensi grow A/B, and I bet you will never come close to reaching 16ml/gallon each part, while growing amazing plants.

Be careful using lemon/lime etc as pH down, they can cause all kinds of bad stuff to grow in a warm DWC reservoir.

Dutch Master Gold "Zone" is a sterile environment, I would rather have a living environment with the beneficial bacteria/fungi...make sure you have good DO (dissolved oxygen) content in the reservoir with a good air stone/ pump combo.

With LED's you can cut back on the nutrients a little, I have grown with LED's and helped many with LED's for a while now and notice I don't need as much nutrients (beneficial bacteria/fungli helps with that too), but add a little CAL-Mag every other nutrient change to help since LED's will make the plant use more in some strains. When the plants are small and young like yours, keep the LED at 18"-20" away from canopy. Also, go ahead and put them on a 18 on - 6 off light cycle.

 

[flexy123]

I had serious yellowing, actually WHITEning of my seedlings, not only the MJ but also my Chillies and whatever.
I added CalMag and it did wonders!! So yes, it's true when many people tell you use CalMag when you grow with LEDs!

 

[grapenut]

Update:

After 24 hours of being flushed and running an aggressive strength of gold zone there are minimal changes to the top of the plant but quit a significant change in root zone. The new roots more than doubled in size since I last checked.

At this point im wondering a few things:
1) When should i start her back on nutes (and what strength)
2) What should I do with the brown slimy roots if anything at all (will they fall off?)
3) I slightly adjusted her stalk in the neoprene collar so that she is now closer to the water, will this cause any significant amount of stress?

 

[madsdad4ever]

man that sux i hope u get it figured out i wouldnt cut the root off but who knows i could b wrong wouldnt b the first time

 

[BuddroGreen]

1) After flushing for 3-5 days with 5.8pH adjusted water, I would only use 5ml/gallon each part Sensi A/B, the bottle states 2ml/L or 8ml/gallon for small plants, that's your plant. Since you're bringing her back from major stress & shock, I would go a little less than the recommended strength, so 5ml/gallon should be a good starting point. From there slowly raise your ml/gallon of each part A/B. (5ml/gallon part A/B for a week, next week 6ml/gallon, next week 7ml/gallon...etc etc) As I stated above I don't go over 10-12ml/gallon each part of my AN GMB(grow,micro,bloom) when in the 4th-5th week of flower.

2) The roots look better with the zone, just keep running the zone...that's why I was saying run some bennie's, the bacteria especially Tricoderma bacteria will break down that old root & slime, and the Mycorrhizae fungi will colonize the root ball and keep it from happening again. Just remember zone is a sterile environment...meaning not living, with plants I prefer a living environment, it's all preference of course.

3) You should be fine with the re-adjustment, also, the leaves you see that are brown & brittle, they will not come back to healthy, they are done, they will eventually fall off, just worry about the green parts you have now and going forward.

 

[grapenut]

Root problem was solved and I have been main lining the plant, she currently has 8 tops (I plan on going to either 16 or 32).

I however have run into a new issue, there is a brownish splatter with a yellowish tint forming around the larger fan leaves. From the images ive seen it looks to resemble a cal mag deficiency the most.

I am currently running half strength nutes, would moving to full strength possibly solve this, or am I going to have to find a suitable additive?