Planting for the first time, growing slowly, please help

[CN-man]

I have asked this question before when these plants are 20 days old.

I added perlite ventilation and better lighting. Feeding about 200PPM of nutrition.
The situation has improved a bit, but now she has not grown up. This makes me very confused, I don't know where I am doing wrong.
The light is CREE CBX3590 70W. I only water the coconut soil when it is half dry. PH value 6-7 (I am not sure, my test instrument seems to have problems).
Their leaves don't seem to grow much. Like they have dwarfism

 

[CN-man]

My English is not very good, I hope you guys can understand what I am talking about.

 

[macsnax]

Bump it up to 300ppm at a pH of 6.3. And feed more often, coco is different than soil. You don't want the top layer of coco completly drying out.

 

[Obepawn]

PH is too high bro. For coco you should be around 5.5-5.8

 

[CN-man]

Bump it up to 300ppm at a pH of 6.3. And feed more often, coco is different than soil. You don't want the top layer of coco completly drying out.

So now I have to feed more nutrients and lower my PH value?

 

[CN-man]

PH is too high bro. For coco you should be around 5.5-5.8

Thank you, so you think this may be a PH problem?

 

[hellmutt bones]

Check ph

 

[macsnax]

So now I have to feed more nutrients and lower my PH value?

Ya for the most part I run at 6.3 in coco, plants are very happy.

 

[principlesarelife]

What are leaf temps? How's the air flow in your grow space? What's your relative humidity?

 

[CN-man]

What are leaf temps? How's the air flow in your grow space? What's your relative humidity?

I removed the tent. Opened the window.
Then the temperature is 30-32 degrees Celsius. A little hot
Humidity is 50-60%

 

[CN-man]

Ya for the most part I run at 6.3 in coco, plants are very happy.

I corrected my PH test pen. After watering PH5.8, the water came out at pH 6.3. PPM230. Now I don't think it is a problem with PH...

 

[CN-man]

What are leaf temps? How's the air flow in your grow space? What's your relative humidity?

China is now summer with an average temperature of 30 °C. I live in the subtropics. I can't think of a way to lower my temperature. I can only add two more fans.

 

[principlesarelife]

86-89.6F is really hot. You'll need to up the humidity & if possible keep it from going past 30c

 

[principlesarelife]

https://www.questclimate.com/vapor-pressure-deficit-indoor-growing-part-3-different-stages-vpd/

Paste the formula (towards the end of the article) into excel & plug in your grow environment variables to calculate your plant's transpiration. I think it's supposed to be between .4-1.2 with .8 being optimal.

If you up your RH you'll need effective ventilation or mold will become problematic.

 

[macsnax]

The thing is that I can see your coco is dried out. Your temps aren't favorable either, but letting coco dry out is a big no no. You'll see twisted leaves and a variety of other issues.

 

[CN-man]

The thing is that I can see your coco is dried out. Your temps aren't favorable either, but letting coco dry out is a big no no. You'll see twisted leaves and a variety of other issues.

Thank you, yes, the leaves have become light green and look even white. So now I need to increase the humidity or lower the temperature. is this correct?

 

[CN-man]

https://www.questclimate.com/vapor-pressure-deficit-indoor-growing-part-3-different-stages-vpd/

Paste the formula (towards the end of the article) into excel & plug in your grow environment variables to calculate your plant's transpiration. I think it's supposed to be between .4-1.2 with .8 being optimal.

If you up your RH you'll need effective ventilation or mold will become problematic.

Thank you for your help, but, sorry, my English is very bad, I looked at the formula, I can't understand.
So How much humidity do I need to increase when the temperature is 89F?

 

[principlesarelife]

the formula is copied & pasted into microsoft's program, excel

ideally, you'd want a heat gun to read your leaf temps to determine how hot or cool your plant is

i'll make a conclusion by basing it off:
the VPD formula
my room's conditions of +4 degrees Fahrenheit of leaf temp from grow room temp

89f air temp
93f leaf temp
you'll want 96-97% RH with good air flow for the optimal .78-.83 VPD range

at that high of RH you're at a higher risk of mold & powdery mildew. that can be negated with effective grow room ventilation


that's just so dang hot for your babies, man. if you can get a humidifier & some fans to gently blow the humidifier's cool mist straight onto your girl, that will help with your hot temps

 

[macsnax]

Thank you, yes, the leaves have become light green and look even white. So now I need to increase the humidity or lower the temperature. is this correct?

Ya let @principlesarelife get you squared away on your vpd, and don't let the surface of the coco dry out. You'll be on the right track then.

 

[BadAssBill]

The thing is that I can see your coco is dried out. Your temps aren't favorable either, but letting coco dry out is a big no no. You'll see twisted leaves and a variety of other issues.

I'm new to this as well, can you explain why it is so bad for coco to be drier?