First Time Grow Using HP4S LED Light Temp & Humidity & Topping

I am using a HP4S LED Grow light and getting really good results. I started from seed germination on the 23rd of November. This plant is growing exceptionally fast but I did make the mistake of putting it into a 5 gal pot from seedling. I seem to have overwatered the plant and having a hard time controlling the temp and humidity. The average temp hum. prob. sits around 85 degreees and 30%. I am using a timer on my exhaust fan because it being on all the tiime sucks the moisture out of the air and the humidity will drop to 15% and will not rise. I run it for 1/2hr every half hour alaong with your basic tornado fan. I am using my closet to grow and have put up scrim paper on the walls and an exhaust coming straight from the light to exhaust fan and then outside. Can anyone help me out with stablizing the temp & Humidity? Am I on the right track or is there something else I can do?

  • Is it the 300w or the 1000w?

    Saint Skinny   Dec 10th 2017
  • Its an led light suppose to take the place of a 1000w hps heat is very low. My plants are drooping pretty bad from overwatering so I have turned the humidifier off with efforts to try and dry out the soil. Now I need help getting my plant to look normal again after over watering. PLEASE HELP

    Rondog   Dec 11th 2017
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2 answers

  • looking at the VPD chart, the high temp and low humidity should be helping your plant transpire water faster, which will help pull water out of your plant/soil. So you did the right thing by turning off the Humidifier. The best thing you can do for now is to leave it alone and let it get rid of that excess water. 


    EDIT: hey bro I was thinking about your question and did a little more research. turns out that in response to low RH (or very high transpiration) some plants will close their stomata (their breathing holes) to prevent excessive water loss. Also, when your plant is in an environment with high transpirtion, you should be lowering the strength of your nutrient solution (mainly when using synthetic fertilizers), since more transpiration leads to more water uptake, which would lead to more nutrients consumed. (you should be OK in with the foxfarm soil as far as that goes, organics aren't "force feeding" your plant like synthetics. As long as you're not showing signs of nute burn you should be ok.) But I'm thinking it may not be a bad idea to try getting your temp down and/or your humidity up if you can. 

    If your into getting all geeky about plants, like I am, Check out Everest Fernandez, he's got a couple fantastic videos on VPD. and TONS to help people starting out. The one video dealing with your situation is called 'VPD too high?', but if you have the time you should watch his video explaining VPD called 'Humidity 102: Vapor Pressure Deficit — VPD Chart' that gives the basics of VPD.


    • Thanks! Much appreciated!

      Rondog   Dec 11th 2017
    • posted by

    Here is a photo of the plant. Please verify this is overwatering. I have not fed it any nutirents yet at all. I am using happy frog soil by fox farm. Thanks

    • I don't see a pic broski

      Saint Skinny   Dec 12th 2017

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