. If not, try just adding more calcium. More magnesium probably won't hurt. Probably. Unless you're giving it too much now, in which case... But an extra dose of your combo-bottle will probably work if you don't have an alternate source of Ca. Being in the middle of flower, you probably wouldn't want to use calcium nitrate. Er... Unless you reduce the amount of nitrogen you're giving them via other components a bit, I suppose.
well I usually add the cal mag in waterings only. I usually water and feed once a week. they showed early in veg they needed alot of it. So I stayed at where I wasn't seeing any signs after I started using it. Since I'm headed into the 6th week of flower could do it be the plant pulling what's left from the leaves ?Once a week? You figure the other six days, they don't want any, lol?
Seriously, though, and without a picture... my guess is calcium deficiency. Or possibly too much magnesium, which can equate to a Ca deficiency (in practical terms), but that's rare.
If you're also showing possible signs of a magnesium deficiency, give more of your calcium + magnesium product - probably on one of those other six days
Here's pics taken a few moments ago. Flowering time in white widow is about 8-10 weeks so I think I can make it to the finish line.
