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Correcting Runoff In Rock Wool

Discussion in 'Nutrients and Fertilizers' started by GrowForJoy, Oct 24, 2018.

  1. Hello again everyone, and thanks for coming to help me diagnose what I am assuming is an issue with Ph runoff.

    I am growing from seed in rock wool watering by hand till the plants get bigger. I just watered one plant with 315ppm 5.7ph water and the runoff was 150ppm and 6.6ph. As I am new to growing I understand I have a lot to learn, and as such I have done a lot of research but I seem to find a lot of conflicting responses or the answers are for coco.

    Night temps hit 19c - 20c (66 - 68 ) day temps are 23c - 24c (73 - 75 )
    night humidity is around 42% and daytime humidity is 53%

    Why is my runoff ph so high? I am assuming a lower ppm is good as it means the plants are taking up nutrients, but how much lower should it go?

    Just for some extra info, I am using advanced nutrients.
  2. Is this not an issue? I ran nutrients through all 4 plants and it was the same result for all of them.
  3. the run-off will rise a bit because of residue limestone in the blocks, they'll eventually get a bit lower over a short time when the RR stabilizes,I've had blocks trap nutes at times that can also make the run-off stray on the low side, if that happens, just flush it out the block with a light bloom( @ around 250ppm's) only [email protected] ph 5.8
  4. Measuring runoff in rockwool is pointless. Whats going on inside the block where the roots are and whats running out will be different. You will be chasing ghosts. PH and PPM go up and down inside the cube during the wet/dry lights on/off cycle. Just make sure the feed PH (don't go over 5.8) is always solid and watch the plants and what they are doing. If you are hand watering seedlings and young plants in bigger non quick drain rockwool cubes you might water 2-3 times in the first 1-2 weeks if that. Biggest mistake is overwatering in rockwool when they are young.
    GrowForJoy likes this.
  5. Thank you sir, this is exactly the information I was hoping to get. I water every 3 days roughly so it seems like I'm on track. Plants seem to be small for how far along they are but as its my first time I didn't have optimal environment for the first two weeks, but everything seems to be great now.
    cemchris likes this.
  6. Yeah usually you will have a semi stall the first 7-10 days after you transplant them from rooter cubes. They arent really stalling per say just all the action is going on in the root zone. Once the tap out of the bottom of the cubes they go nuts. Sounds like you are on track.