Nitrogen problems? Week 2-3 of bloom and yellowing leaves.

[VgAce]

Plants are starting to yellow. Is this a simple N deficiency?
They are in Grodan Delta 4 cubes. Watering them every other day to make sure they are not over-watered. They do not appear over or under-watered. The leaves aren't dropping or cupping.

Week 2-3 of bloom. The other strain still looks green. Using Dyna-gro Bloom with Orca and Silica.

Temp is about 70F.

PPM is about 800. I could increase it to 900 or add plain N.

Last 2 pics are under the HID light but you can still see a the top parts yellowing.

 

[Hayron1088]

Looks like over watering to me

 

[VgAce]

Looks like over watering to me

I wait until the cubes are dry but not bone dry. My last grow I ruined because I way overwatered them. This time I have drastically cut back the watering. What makes you think it is overwatering?

 

[Buds Buddy]

Looks slightly overwatered. How close is your light ? I see some twisting & cupping of the leaves like the light is too intense. Are you using a PK Booster ? Looks like you may need one for the yellowing leaves.

 

[VgAce]

Looks slightly overwatered. How close is your light ? I see some twisting & cupping of the leaves like the light is too intense. Are you using a PK Booster ? Looks like you may need one for the yellowing leaves.

What exactly does a PK booster do?

 

[Emilya Green]

I will throw out another opinion... I think she is slightly underfed and that this is a simple potassium deficiency. Now that you are in bloom, nitrogen is not nearly as much needed, but the needs for potassium and phosphorus and many other micro nutrients have skyrocketed. I recommend that you increase your bloom feed rate by 25%.

 

[Hayron1088]

@Emilya Green Nice catch right there, I didn’t think about that. Growing organic has made me a bit “lazy” when it comes to feeding. When the leaves cup like that it could be under feeding also?

 

[VgAce]

I will throw out another opinion... I think she is slightly underfed and that this is a simple potassium deficiency. Now that you are in bloom, nitrogen is not nearly as much needed, but the needs for potassium and phosphorus and many other micro nutrients have skyrocketed. I recommend that you increase your bloom feed rate by 25%.

I took one of the plants out and really looked at it. I don't see any drooping, or any wilting. I don't think the plants are under or over-watered. I think they just need some of that PK. I had like 30ML so I added that and upped the bloom nutrients a bit. I also recalibrated my PH meter. I know that Grodan told me to keep the PH at 5.6 to 5.7 but I think that is a bit low.

Anybody know what they recommend for PH? I could not find any good data online.

I think this is a simple nutrient deficiency caused by incorrect PH, or too low of bloom nutes.

 

[Emilya Green]

I took one of the plants out and really looked at it. I don't see any drooping, or any wilting. I don't think the plants are under or over-watered. I think they just need some of that PK. I had like 30ML so I added that and upped the bloom nutrients a bit. I also recalibrated my PH meter. I know that Grodan told me to keep the PH at 5.6 to 5.7 but I think that is a bit low.

Anybody know what they recommend for PH? I could not find any good data online.

I think this is a simple nutrient deficiency caused by incorrect PH, or too low of bloom nutes.

as far as pH goes, stick with the recommendations that got you to this point. I don't see any reason to adjust something that isn't broken. I think upping the bloom and adding additional PK is the perfect move. Move slowly, and give this adjustment 2 or 3 watering cycles to see its full effect before changing something else.

 

[Emilya Green]

@Emilya Green Nice catch right there, I didn’t think about that. Growing organic has made me a bit “lazy” when it comes to feeding. When the leaves cup like that it could be under feeding also?

There isn't a lot of leaf cupping under the HPS light, but it does look like a reaction to a bit too much light or heat at the top of the canopy. I would back the light up another 6 inches or so if possible. I also noticed that the plant moved out onto the washing machine to take a natural light picture was not showing any of this cupping at all... that makes me think again of heat in the grow room.

 

[CaptainLucky]

Looks slightly overwatered. How close is your light ? I see some twisting & cupping of the leaves like the light is too intense. Are you using a PK Booster ? Looks like you may need one for the yellowing leaves.

Oops sorry hit quotes accidentally. CL

 

[VgAce]

There isn't a lot of leaf cupping under the HPS light, but it does look like a reaction to a bit too much light or heat at the top of the canopy. I would back the light up another 6 inches or so if possible. I also noticed that the plant moved out onto the washing machine to take a natural light picture was not showing any of this cupping at all... that makes me think again of heat in the grow room.

Not possible to move plants back. This is in a Volksgarden circular rotating drum.

 

[Buds Buddy]

What exactly does a PK booster do?

Emilya kind of answered that when she said that more Potassium & Phosphorous is is used in flower. N- Nitrogen, P- Phosphorous, K or K2O - Potassium. A PK Booster adds P & K = Bloom Booster, gives the plant the added P & K that's needed with some nutes to prevent the yellowing of leaves & supply the plant with more of what it needs during flower.

 

[SmokingWings]

Oops sorry hit quotes accidentally. CL

I get around those by backspacing the quoted material or block it all and deleting. Doing it right and the quotes disappear and everything is back to normal. Might have to block the quote and hit "cut" or something similar if on a cell phone.