VPD or DLI

So, with my current grow situation, I can only seem to get one thing dialed in. It’s either my VPD is great, or my DLI is great. Can’t get em both dialed in. Which would be the most important?

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5 responses to “VPD or DLI”

J Mystro

01/27/2024

VPD and DLI are not dialed in together with one device. Humidity levels and lighting are controlled separately. Do you not have a dehumidifier and lighting controller? They are both equally important.

Richard Horton

01/27/2024

My circumstances require a humidifier, but yes I have both
Currently playing with light height to control temp which is making humidity easier.

J Mystro

01/30/2024

What lighting are you using? I remember temps being an issue with HID but now with LED, intensity is more of a concern than heat in relation to light height. Sounds like you’re using HPS if light height (radiant heat) affects canopy temps. I kept 600 watt HPS at about 18″ while 1000 watt HPS I kept about 24″ above canopy.

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1. Richard Horton
  
  02/01/2024
  
  Great news sir, I finally got it. It’s not an ideal situation, but it’s working. I’m using an LED from HLG. My issue was all my fault. My planters completely fill the floor space in my tent. Leaving no room for a humidifier, other than splitting the difference and setting it on the rim of my planters. My current humidifier is tall and narrow,.so I really wanted to keep my lights high, above the humidifier, which meant I had to turn the intensity up to maintain DLI. Doing so raised my temperature higher than I wanted. Ended up lowering light, and turning dimmer down. I don’t think it’s ideal to have the humidifier above light as it keeps the humidity higher in the top of my tent than it does in my canopy area, but that’s where I’m at.
  Once again,.thank you sir, as I always look forward to your advice.
  
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Soup

02/02/2024

Use your hvac equipment to control the temps and humidity in the room outside the tent, then use ventilation with a smart controlled fan to fine tune the environment inside the tent.

This should help you get more control of your environment. That way the lights aren’t having such a huge effect on VPD.

https://growerslove.com/ventilationguide/