DWC Help Required - PH/PPM Increasing!!

[EroGrow]

Hi there,

First time DWC grower, ill give you some quick stats.

Im using Tap water @ .5EC (250PPM)

During the first week of veg i ran 1.0EC with no variation in PH/EC - plants seemed happy

Now i am at week 2.5 and the EC/PH are increasing at a rapid rate. for example, last night i topped up to 1.2EC 5.8PH - In the morning it was reading 1.4EC @ 6.2PH. The lower leaves are yellow and are curling upward. Im getting mixed messages as to what the problem could be but my conclusion is that i need to factor in my Tap water when calculating EC so in actual fact my plants are being underfed since 600-250=350PPM of nutrients which seems to be way less than recommended. I have spent some time looking over the forums here and the recommended veg EC should be around 1.2-1.6 mid-late veg (1.8 if you factor in the EC of the tap water)

I want to make sure im heading in the right direction before i make further adjustments. Any advice is greatly appreciated !

 

[Mañ'O'Green]

@EroGrow Welcome to AFNThe PPMs of your starting water is too high. but before we get started we could use some more information.

Please fill in this form: (copy and paste part is below, this first one tell what specifically to include)

-Problem: (brief description)
-Medium/grow method: soil; soilless-- coco, or peat based like Promix, etc. (please provide the actual product name); DWC, NFT, etc.
-Feed and supplements used: include brand, dosage/strength, frequency of feeding and watering (alone); method-- by hand, drippers, rercirc' or drain-to-waste,... N-P-K #'s too if you can!
-Water source: RO/DI; tap- dechlorinated-?..... EC or TDS reading; pH (don't bother with this on RO/DI, do bother with TDS/EC though to confirm it's working well enough)
-Strain and age
-Climate: night and day ambient T and RH%; res' temperatures; any extremes in T/RH% exposure
- Light used: HID, LED, COB, combo of,... wattage; light cycle hours (20/4, 18/6 , etc.); distance to tops....
-Additional info: PH in the root zone. How long have the plants been affected?...How fast did symptoms appear?... Anything else you think might be relevant..

--Pictures including WHOLE PLANT PICS, and troubled leaves.. use normal light or flash as other light sources ruin color rendering, critical for diagnostics! turn off the grow lights.

✂ - - - - - - - - - - -
(copy and paste)-->

Problem:

Medium/grow method:

Feed: and supplements used:

water source:

PH in the root zone:

Strain/age:

light used:

Climate:

Additional info:

 

[EroGrow]

Problem: As above, Yellow & curling inward lower leaves. PH/PPM Rising. I have lowered to .8EC (400PPM) however still saw rapid rises. Increased to 1.2EC and still seeing rises. Do i need to go up as much as 1.6EC to compensate for the tap water .5ec thus making the true nutrient EC value 1.1
( i can supply photos later when i get home)

Medium/grow method: DWC 20ltr buckets

Feed: and supplements used: Maxibloom (lucas method - previous success using coco) 1/4 str for 2 weeks | 1/2 str 2-4 | full str rest of the grow until flush. Lucas reccomends 7g per gal at max str however ive tuned it down to 5g per gal

water source: Tap water @ 250ppm or 0.5EC

PH in the root zone: Set at 5.6 and will rise to 6.0 overnight.

Strain/age: Northern lights/ Charlottes sister autoflowers (seperate buckets) both just over 2 weeks veg

light used: 300 (130real watt non china LED) Full spectrum at 18/6 22" from canopy

Climate: 55RH constant sitting at 20-25c with water temps at 20c

Additional info: Current readings are 6.2PH @ 1.2EC (600PPM) with both PH and PPM rising.

Am i seeing nitrogen deficiency as the bottom leaves are curling inward and turning yellow? This means i am underfeeding hence the reason why PH and PPM are both increasing since it is causing leeching of nutrition. is the tap water considered in the final PPM reading or is it to be subtracted? If the latter applies then my current EC .7 which would be considered too low for second week veg?

 

[Mañ'O'Green]

Ok so as I mentioned before the starting water in DWC needs to be below 200 PPM. otherwise you are starting out with too much calcium carbonate. As the water aerates the calcium carbonate is precipitating out and this is what is part of what is causing your PH swings. Mix in some distilled or from a vending machine or RO. I would use nutrients at 70% of this chart. and use all of the products in the "Simple Program at the appropriate time.

The water level in the reservoir needs to be maintained at a constant level. This will help prevent EC spikes when the plant is drinking more water.

Not counting your starting water PPM I begin at 500PPM of nutrients and increase strength by 10% each week until a bit of tip burn then back of 10%.

I use the Hanna Scale:

 

[Mañ'O'Green]

Are you using MaxiBloom in veg? Not enough N in that you should be using MaxiGro until flowering is under way!

 

[EroGrow]

Are you using MaxiBloom in veg? Not enough N in that you should be using MaxiGro until flowering is under way!

Correct, i am using maxibloom throughout the whole grow. Previously i have successfully grown 2 auto plants in coco using just the maxibloom. Are you saying the same conditions wont apply in DWC? You mentioned that the starting PPM should be @200. I am now into day 15 so where would you recommend the PPM be at this stage? 350ppm is causing an increase in both PH and PPM. Am i underfeeding?

 

[Mañ'O'Green]

Correct, i am using maxibloom throughout the whole grow. Previously i have successfully grown 2 auto plants in coco using just the maxibloom. Are you saying the same conditions wont apply in DWC? You mentioned that the starting PPM should be @200. I am now into day 15 so where would you recommend the PPM be at this stage? 350ppm is causing an increase in both PH and PPM. Am i underfeeding?

Well you are not going to get the nitrogen you need in veg by using bloom nutrients period! So there is no way to get enough nitrogen without causing lock-outs of K, Mg, Fe,Mn, Zn, and/or Cu.

You need to learn about Liebig's Law of the Minimums to understand that when the balance of fertilizer is P-K heavy the plant will not take in enough nitrogen for optimum growth. This is why so many nutrient lines have two phases. The fact that it worked for you before does not mean it will work here and your previous coco grows may have been more successful had you used the veg nutrients?

What I said is your tap water (starting water) should never be over 200 PPM. You need to mix RO, or Distilled water with it to get it below 200 PPM. 100 PPM would be a good target.

Now not counting the starting water PPM to your nutrient PPM should be about 550 PPM in week 2 (plus your water of 250 = 800 PPM total). The nutrient's strength does not cause the PH to change. It is the aeration causing calcium carbonate to drop out of solution. Your Tap water is full of calcium carbonate. This makes it difficult to keep PH in range.

I PH my reservoir at least twice a day and my starting water is 80 PPMs. The roots of the plant exude carbohydrates and other substances that cause the PH to fluctuate. When you have a sudden drop in PH like into the 4.5 range in a matter of hours this is the signal to switch to the bloom nutrients.

 

[Simplicio]

Your tap water ppm is probably too high.
I switched to RO water because my EC=0.38 tap water was producing unhealthy plants.
We have no idea what the ppms are, or whether there are things in tap that don't produce ppm, but can harm plants.

I ran across this strategy a few years ago, and it works well:
If ppm rises from day to day, plants are drinking more than eating, so reduce ppm.
If ppm falls from day to day, plants are eating more than drinking, so increase ppm.

When I do this, my plants usually ask for a maximum of about EC=1.0 or less.

 

[EroGrow]

Well you are not going to get the nitrogen you need in veg by using bloom nutrients period! So there is no way to get enough nitrogen without causing lock-outs of K, Mg, Fe,Mn, Zn, and/or Cu.

View attachment 1223125

You need to learn about Liebig's Law of the Minimums to understand that when the balance of fertilizer is P-K heavy the plant will not take in enough nitrogen for optimum growth. This is why so many nutrient lines have two phases. The fact that it worked for you before does not mean it will work here and your previous coco grows may have been more successful had you used the veg nutrients?

What I said is your tap water (starting water) should never be over 200 PPM. You need to mix RO, or Distilled water with it to get it below 200 PPM. 100 PPM would be a good target.

Now not counting the starting water PPM to your nutrient PPM should be about 550 PPM in week 2 (plus your water of 250 = 800 PPM total). The nutrient's strength does not cause the PH to change. It is the aeration causing calcium carbonate to drop out of solution. Your Tap water is full of calcium carbonate. This makes it difficult to keep PH in range.

I PH my reservoir at least twice a day and my starting water is 80 PPMs. The roots of the plant exude carbohydrates and other substances that cause the PH to fluctuate. When you have a sudden drop in PH like into the 4.5 range in a matter of hours this is the signal to switch to the bloom nutrients.

Thankyou - i appreciate your expertise

 

[EroGrow]

Your tap water ppm is probably too high.
I switched to RO water because my EC=0.38 tap water was producing unhealthy plants.
We have no idea what the ppms are, or whether there are things in tap that don't produce ppm, but can harm plants.

I ran across this strategy a few years ago, and it works well:
If ppm rises from day to day, plants are drinking more than eating, so reduce ppm.
If ppm falls from day to day, plants are eating more than drinking, so increase ppm.

When I do this, my plants usually ask for a maximum of about EC=1.0 or less.

This is true however PPM can also rise due to leeching, which i think is my problem. Noticeable N deficiency as per yellow leaves and curling upward.

Since the original post PPM has been static at 600PPM so i think im heading in the right direction however still waiting for the lower leaves to come back to life