Need help with this deficiency please

I've been searching and the pictures and descriptions just look to common maybe someone has some insight....

Strain is white widow / gold leaf, only a week into flower.

Running a current culture hydro setup 9 plants.

Just using sensi bloom this round , as before I was using all the boosters and burning.. the leaves on the top are really yellow and actually even getting brittle, bottom fan leaves dying as well.

Hope someone checks this out... don't want to lose this harvest

Looks like a sulfur deficiency to me along with some mag def too. Epsom salts will supply both and it wouldn't hurt to foliar feed some to them for quicker results.

Shouldn't be happening that bad with Sensi if at all. pH should be OK with the Sensi unless there is something in the water you are using that is blocking some of the micro nutrients like Mg and S. Too much Ca can block them out.

More info would help. PPM, water source and the ppm of your water. pH of the nutes and the water but shouldn't be an issue with the Sensi if it's the pH Perfect stuff.

the yellowing starts at the leaf tips and works its way back. we need you to tell us more of the grow, the temps and amounts of ppm you're using. are you using both a and b, or just one of them? websites say that bloom is a foundation fert so I'm wondering if you're suppose to be adding something else.
maybe this will help.
https://thegrowshow.org/current-culture-feeding-schedule

I agree with above I'd start with some cal mag or epsom salt .....light leaf with dark veins usually mean a mag def ...GL

I don't see any signs of Ca def so if it's Ca causing the lockout adding CalMag will make it worse. And as long as both parts of the Sensi are being used then that's all they really need. I was using the Sensi Grow for veg and the Connie for Bloom the last couple years and the only problem I ran into was N burn later in flowering so switched to the 3 - part so I can cut back on N to prevent the burn.

Mg deficiency alone doesn't cause new growth to yellow at the same time like low S can. If CalMag isn't currently getting used then it's unlikely Ca toxicity is causing the problem but something is.

That link to the nute schedule you posted PolishP isn't near the same as what Advanced recommends in it's useless feed schedule but they use the various things in the same way it took me years to figure out and how I'm feeding now. Start a half dose of bloom a week before switching to bloom and taper off everything the last three weeks or so near the end.

Wish I'd had that one years ago.

it wasn't long ago that people were burning the heck out of their plants with Advanced. It was a 20-20-20 fert and people didn't know any better but to feed full strength. Making this worse is the crystalline fert structure, as opposed to liquids or powders, tend to be very strong.

polishpollack said:

it wasn't long ago that people were burning the heck out of their plants with Advanced. It was a 20-20-20 fert and people didn't know any better but to feed full strength. Making this worse is the crystalline fert structure, as opposed to liquids or powders, tend to be very strong.

Click to expand...

As far as I know Advanced Nutrients has never been a 20-20-20 crystalline nutrient. All their base nutes have been in liquid form since I started using them in '01.

Even when a nute is strong it's only because the person using them doesn't know how to use them properly that they are burning their plants. It's like thinking if you can drink a liter of beer and not be drunk you can drink a liter of vodka and not get drunk.