yellowing fan leaves

Good day folks,

Looking for some insight on an issue with one of my plants.

I currently have two plants under 400 watt HPS, which were switched over to 12/12 July 6th.

One of them (blue dream) is all green, showing pistils on many bud sites and overall looks very happy.

The other ( blueberry ) I've noticed that many of the lower/middle fan leaves have started yellowing and showing some brown spots. I can take a picture, if it'll help out.

Now, while the plants were in veg under CFL lighting i was giving 0/5/10 micro/bloom which the plants seem to enjoy. When I started into flowering I started using the more powerful light and read that lucas formula should be used at 0/8/16. My last couple of feedings were used at this strength. Do you guys think the yellowing of the leaves is just the plant using the energy from these leaves towards flowering or a nutrient problem? I haven't PH'd my nutrients/water as I don't have a pH, or TDS meter. I have a shitty 3 in one moisture/light/pH meter but I trust that very little.

I have read that yellowing leaves in flower is normal, but 2 weeks in? I would think maybe a flush would be beneficial, however the blue dream looks like it's thriving with the exact same environment.

Temps are generally 26/27 deg C, with RH @ 40-50 depending on outside weather.

Thanks for any advise you guys can throw my way.

Cheers!

yeah would need some pics to get a better look, but brown spots are usually manganese deficiency and nut burn is the tips getting browned and nothing else but if its the lowers they could just be shedding their leaves as they get new ones

Sure thing. Here are a few pics.

First few are from leaves from the middle of the plant down, and the last two are towards the top.

Calcium https://www.sensigarden.com/calcium-deficiency-marijuana/

hey jypsydog!

thanks for your reply, it's appreciated.

would you suggest picking up a bottle of calmag, to sort this issue? judging by the article you posted, it looks like it's the deficiency side of the coin eh ..

It's almost always a cal/mag issue. I have gotten into the habit of always supplementing with cal/mag to be on the safe side. Just pick up a bottle it's usually around $20. just always use it.

that's one of things i decided not to buy when I was ordering all my nutes. will know better next time lol.

this is my first grow, so anything that pops up I'm clueless as to what to do. i'm going to order up some calmag tonight, and give her some treatment.

thanks guys.

Don't pay for WATER!!! Order dry Cal/Mag. Free Shipping Too! https://www.greenwaybiotech.com/products/cal-mag
This is where to get your Silica. 7.8%!!! https://buildasoil.com/products/agsil16h-potassium-silicate

Here's a must for Newbie's. And remember... Once you dump it in or on, Tuff going back. DON'T LOVE THEM TOO DEATH! Good Luck!