What type of deficiency/toxicity is this?

[diesel23]

Does anyone know what's going on here? there seems to be a few plants out of the batch that have these yellow,purple leaves. I'm growing in 6inch rockwool cubes. Flooding the table once a day using PBP, LK and CalMag. Ph is between 5.5-5.9. Temps range from 65-83 with RH 50. I'm 4 weeks into 12/12. Any advice would be appreciated.

 

[norcalgreens]

my guess maganess def

 

[KrazyDan]

Did this happen right after a rez change??...looks like ph fluctuated badly locking out P...and some others..FLUSH and redo the rez at a lower EC until they snap back ..i think
KD

 

[norcal215]

flush and hit with cal mag..... look at your roots if they are brown and not cocaine white its a pythium attack hit it with a microhizae

 

[nog]

looks a bit like phospate deff,

 

[Lowman]

One or more elements seem to be locked out. I don't like the fact it's effecting the upper leaves so much. Tells me it's not a mag issue.

If I was you...even though I don't like to do it in flower...I would do a good flush, flush, flush...then feed normal strength nutes. Maybe even give them a dose of veg nutes to bring everything back into balance.

I'm not a rockwool grower...but from what I have read...it can really screw with your ph if you're not on top of it.

 

[danko]

it looks like a molybdenum issue. that is super rare but it happens in cold weather and with color changing strains. it will start in the middle leaves and work its way up. often confused with iron or cooper dif. just a thought. thats what it looks like when i compare it to this book i have that shows all types of disorders and deficiency.

 

[diesel23]

Any idea on how to fix the molybdenum, Danko?

I will do a good flush and pray for the best. It's weird because only about 2 plants out of 100 are like this.