Yellowing leaves on bud site + Purple

[MaskedPlants]

Hey AFN!

Problem: Leaves on the bud sites are turning lime green/yellow and stems are turning purple as well as some of the leaves.

Medium/grow method: Gaia green living soil, 5gal, top dressing when needed

Feed: and supplements used: Gaia green 4-4-4 all purpose and 2-8-4 power bloom

water source: Tap water dechlorinated and Ph'd to 6.4-6.5

Strain/age: Fastbuds CBD Crack day 51

light used: Kingbrite 240W QB, LM301H diodes

Climate: Temps between 73-75 and RH between 35-37

Additional info: I gave her a feeding 2 weeks ago of half the recommended dose of power bloom top dressing, but she started getting burnt tip so I just let her do her thing and water only.

 

[Mañ'O'Green]

Your RH is too low. It needs to be >40%<60%. The purple coloration is genetic and the limey color might be some of that also.

 

[MaskedPlants]

@Mañ'O'Green Got it, thanks for the feedback, I was worried something was off. As for the RH I raised it to 45, thanks again!

 

[low_and_slow]

55% is ideal for the temps you listed. Any idea what your runoff pH/EC are?

 

[MaskedPlants]

55% is ideal for the temps you listed. Any idea what your runoff pH/EC are?

No idea right now, EC pen is still on its way, everywhere I look it says to be between 40-50RH and between 65-80 Farenheit during flowering. Isn't the only downside from a lower RH more transpiration from the plant? I don't mind giving her water more frequently, I'd rather avoid mold with higher RH.

 

[low_and_slow]

Google "VPD curve" and you'll get your answer for ideal RH based on temp. Ideal leaf temps for LED grows are 75-82F, so for most plants that's 40-70% RH.55 is the midpoint.

Transpiration due to low RH means the plant is up taking minerals and salts as well, which can cause toxicity and lockout. If you see the plant looking like it's going the wrong direction, increasing humidity can be a remedial step. Mold is the counter balance to that strategy, but you're not in the "super mold friendly" realm until 70+.

If someone is at 55-65 and gets mold, they always had mold. Being at 40 wouldn't have meant no mold...