Yellow leaves 4 weeks into veg each grow

[BB Boomer]

I have had yellowing leaves last grow and the current one. Always happens around week 4 of scrog veg. I have been growing the same way in vic high supersoil for 20+ years without ever a problem.

The only thing that has changed is I moved and went from city water to well water.
I checked the ppm of the well water and comes out to 340 ppm. I didn't do an analysis so I don't know what the makeup is. I use water only adjusted to 6.5 for growing in supersoil.
My lights on temp runs between 74F and 78F. Lights off temp is 72F.
Lights distance from canopy is 3ft. and par meter reads 500 umols. Last week I did a flush with straight RO and soil is still wet at the bottom half of 20 gal. totes
I also gave the plants a epsom salt folis

 

[pghdave420]

yellow leaves at top or bottom of plant? if at bottom maybe they just eating threw nitrogen fast or the bottom ones not getting any light and dying off. pics would help and im sure more will jump in to help ya

 

[ooof-da]

Most US cities will have their quarterly WQ analytical posted online….may be worth a quick search or a call down to your water district? Must be some micro-nutrients maybe? You have way more experience growing than me.

GL

 

[ooof-da]

Most US cities will have their quarterly WQ analytical posted online….may be worth a quick search or a call down to your water district? Must be some micro-nutrients maybe? You have way more experience growing than me.

GL

Oh sorry I misread your post - you went from city water to well water… my bad

 

[BB Boomer]

I have had yellowing leaves last grow and the current one. Always happens around week 4 of scrog veg. I have been growing the same way in vic high supersoil for 20+ years without ever a problem.

The only thing that has changed is I moved and went from city water to well water.
I checked the ppm of the well water and comes out to 340 ppm. I didn't do an analysis so I don't know what the makeup is. I use water only adjusted to 6.5 for growing in supersoil.
My lights on temp runs between 74F and 78F. Lights off temp is 72F.
SUNSYSTEM 630W lights. Distance from canopy is 3ft. and par meter reads 500 umols. Last week I did a flush with straight RO and soil is still wet at the bottom half of 20 gal. totes
I also gave the plants a epsom salt foliar feed. No signs of improvement so yesterday I gave a potassium sulfate foliar feed. Plant symptoms seem to be classic K deficiency including yellowing from leaf margins inward while veins stay green. Eventually the tips and margins of leaves turn brown. Lateral stems from main branches are really weak and bend easy. Growth has come to a virtual stand still.
I am guessing that the plants stay green and grow well until about 4 to 5 weeks into veg until a eventual calcium build up lockout occurs? That's why they grow good in the beginning?Is it overwatering although never had such a problem in the past? Could it be a possible calcium build up until lockout occurs? Or is it even a potassium lockout but something else instead?
Soil is still wet from the flush so haven't given any more water since then.
Really getting frustrated. No remedies seem to be working and beginning to feel like I don't know how to grow anymore. Any help is greatly appreciated.
Pictures show the open setup and the plant symptoms. The pic with two leaves is from Cereal Milk and the picture with seven leaves is from Romulan and shows the progression of the problem starting with the leaf at top of the arrangement and eventually turning into the bottom three leaves with the crispy brown spots.

 

[BB Boomer]

There really isn't any bottom leaves left. Just the canopy in.the scrog screen so I guess the bottom and top are the same leaves.

 

[BB Boomer]

There really isn't any bottom leaves left. Just the canopy in.the scrog screen so I guess the bottom and top are the same leaves.

I removed the bottom leaves when they got shaded out by the canopy.

 

[BB Boomer]

Definitely feel safe to rule out nitrogen deficiency. Leaves don't turn ALL yellowing including the veins and they aren't dropping off the plant.

 

[pghdave420]

was just a guess with no pics. maybe mag defi since the veins still green ,but you seem to be on top of that by giving epsom.

 

[nxsov180db]

My guess is most of your well water ppm is calcium, and it’s locking out magnesium.

 

[BB Boomer]

I am pretty much thinking the same thing although I thought a potassium lockout. I am treating for both mag and potassium. Sure hoping one of them works. Just got a 100 gal RO system setup so won't be using the well water for growing anymore.

 

[nxsov180db]

Pretty sure too much calcium locks out potassium too so you might be on the right track

 

[curious2garden]

Pretty sure too much calcium locks out potassium too so you might be on the right track

 

[Budzbuddha]

Definitely looks like potassium deficiency - yellow margins and mimicking nute burn ( tips ) .
Well water could have heavy mineralization ( calcium ) which would antagonize other elements and its uptake.

You could try to compensate with potash.

 

[curious2garden]

Definitely looks like potassium deficiency - yellow margins and mimicking nute burn ( tips ) .
Well water could have heavy mineralization ( calcium ) which would antagonize other elements and its uptake.

You could try to compensate with potash.

Potash for a K def lol next thing you'll be telling him to pee on his plants!

 

[Budzbuddha]

Potash for a K def lol next thing you'll be telling him to pee on his plants!

Well now you did it ….. Release The Peekracken !

 

[BB Boomer]

LOL

 

[Hollatchaboy]

Langbeinite.