Mimosa Punch, 32 days, clawing leaf tips, stunted growth

[Mangos]

Problem:Clawing leaf tips, stunted growth, yellowing bottom fan leafs

Medium/grow method: Plagron Light Mix in a 20L Airpot

Feed and supplement used: Sensi Bloom A&B @1ml per litre. Plant has been getting 350ml every two days. I use pH down and add the feeds between 6-6.3pH.

Water Source: I leave tap water out 48hrs before making feeds. pH is7.5: EC is:0.66

Strain and Age: Dutch Passion Mimosa Punch 32 Days

Climate: 22-28oC RH 20%-50%

Light used: GN Telos-0008 @ 70cm from canopy

The plant has been effected for just over a week, I thought it may be nitrogen toxicity and that she would sort herself out in time as she grew bigger, but growth has all but stopped since then and lower fan leafs have started to yellow and I’m not sure what’s best for her.

 

[Mañ'O'Green]

You are correct about too much nitrogen but the saw tooth is from too much heat and or RH too low? Both factors can slow/stop growth. Your pot looks too dry? PH of your water/fertigation is too high bring down to 6.4.

 

[Mangos]

thanks for the reply Man O' Green.

During the seedling stage temps in the tent were on the high side, around 27-28oC and RH was between 20-30%. I placed a 15L bucket of water in the tent hoping to increase the humidity but it made minimal difference. My last grow I struggled with high humidity in flowering and was looking at purchasing a dehumidifier and this grow I've struggled with low humidity in veg and could have used a humidifier . Might have to look at a double purchase.

I've been lowering the pH of feeds to 6-6.3. I put a litre of tap water though her earlier (pH 6.2) and then gave her a 500ml feed on Sensi Bloom A&B @1ml per litre (pH 6.2) I've never grown in a pot this big before.

Have attached a clearer pictures of the yellowing fan leafs, are they related to the stress or the N toxicity?

Appreciate the help!