4 weeks flower - Leaves turning yellow. N def?

Cann

Well-Known Member
Alright here is a little background: These ladies have been in flower for 4 weeks, they are in Roots Organic soil and have been fed a few bloom AACTs over the last few weeks. They have been fed RO water their entire lives, and therefore have a bit of Cal/Mg issues. To combat this I have been foliar feeding with epsom salts once every few weeks, and about a week ago I applied some Roots Elemental (Cal/Mg supplement) as a top dressing and watered it in. Some of the ladies are showing signs of Cal/Mg issues (yellow leaves with green veins indicating Mg def, and little necrotic patches indicating Cal def) but I am not necessarily worried about the Cal/Mg because it is only on a few leaves and the ladies seem to be pretty happy overall.

My main concern currently is that over the last week a lot of my ladies have started to fade pretty intensely - with a lot of the lower leaves turning yellow and the upper leaves turning pale greenish. I am only at week 4 flower so this is definitely way too early for a regular fade, do you think I should feed them a veg/bloom tea with pretty high levels of N? I have read that feeding too much N in flower will promote leaf growth and not flower growth, but if my plants are showing a deficiency do I really have a choice?

Would it be better to starve them of N and have them potentially be stunted, or feed them N and have them potentially grow a bunch of leaves but not swell up in the buds at all?

Is there anyway that a Cal/Mg deficiency could prevent N uptake? I know that some nutrients affect each other in this way so this is a possibility....


Any input would be greatly appreciated, I want to get as much out of these ladies as I can :bigjoint:

Here are some pictures, the first three are of the necrotic spots (Cal def?) the fourth is of one of the leaves I think has Mg def. The last few pictures are just an overall shot of my flower room - you can see that some plants are deep green and healthy, and others are yellowing like crazy.

They are a bunch of different strains (on a pheno hunt currently) so it makes sense that some would want more food than others etc. leading to yellowing of a few but not others.

If anyone has experience feeding N late in flower it would be greatly appreciated. Let me know what y'all think. Thanks in advance :bigjoint:











 

Silicity

Well-Known Member
get some calmag +, or a good calcium/mag supplement as a calcium def is a bad one and leaves dont recover unlike a mild nitrogen deficiency, calmag + by botanicare has a good source of calcium, magnesium, iron, and a low amount of nitrogen but itll get your plant on the right track. like always make sure you got your ph around 6.2 soil, 5.8-6 for soilless.
 

zack66

Well-Known Member
I've used N up until the 6th week of flower. I use it regular dose for the first 2 weeks of flower then, gradually cut it back until week 6. I prefer to keep them as green as possible right up until harvest. Good luck!
 

Bublonichronic

Well-Known Member
for minor N defs, i like to put 1cup organic worm castings in 5 gallons water and let sit for a day, then feed, usually if its a N def it greens up within a couple days
 

Cann

Well-Known Member
Perfect, I already have an AACT of worm castings and alaska forest humus going, its been bubbling for about 48 hours ppm around 600, I think I'll feed that tonight and see how they react. Also I'll pick up some cal-mg and throw it in the mix.

So the N isnt gonna mess em up at all?
 

Bublonichronic

Well-Known Member
Perfect, I already have an AACT of worm castings and alaska forest humus going, its been bubbling for about 48 hours ppm around 600, I think I'll feed that tonight and see how they react. Also I'll pick up some cal-mg and throw it in the mix.

So the N isnt gonna mess em up at all?
i dunno about PPM....i just use the color of then water for a PPM reading, ahha, but if its a N def, brewed up worm castings are the best thing iv found
 

Silicity

Well-Known Member
not as much during the flowering stage compared to veg, during flowering you give N to mostly keep the plant healthy, yes there is "side effects" but arent majorily detrimental unless you allow it to start dropping alot of leaves.
 

Cann

Well-Known Member
fed them a high N tea with a large dose of Cal/Mg...hoping that this stops the yellowing. If it is a pH issue then it will probably keep getting worse I imagine...potentially my soil is too acidic and I'm getting lockout
 

skunky33

Active Member
Yellowing leaves is normal at this point. I can tell you right now that a leaf that uniformly yellow is just the plant using it's energy in bud production. Your plant thinks it's Autumn. If you pull the leaf it will come right off the plant like on a tree in the fall. If you want to fix it use a little N just a little. You don't even have to though unless the yellow starts creeping into the bud leaves.
 
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