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Correcting Runoff In Rock Wool

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.
 
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
 
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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.
 
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.
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.
 
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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.
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.
 
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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.
It's funny how often I'll google search a question only to find you've answered it on here @cemchris lol.

Mine just shot roots out the bottom last night on day 6 and are noticeably growing now. The blocks are really dry today and when lights come on I plan to hit them with a feeding of 0.8ec - 5.8ph. Does that sound about right? Or is this a good time to ramp up to about 1ec? I'm still a bit unsure how slowly I need to ramp these up.. And should I fully saturate them to runoff now or feed smaller amounts of lower ec nutes for the first couple feeds to encourage more air access? That's how I would treat a peat mix during root grow in. But I'm not sure how different wool is.
 
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It's funny how often I'll google search a question only to find you've answered it on here @cemchris lol.

Mine just shot roots out the bottom last night on day 6 and are noticeably growing now. The blocks are really dry today and when lights come on I plan to hit them with a feeding of 0.8ec - 5.8ph. Does that sound about right? Or is this a good time to ramp up to about 1ec? I'm still a bit unsure how slowly I need to ramp these up.. And should I fully saturate them to runoff now or feed smaller amounts of lower ec nutes for the first couple feeds to encourage more air access? That's how I would treat a peat mix during root grow in. But I'm not sure how different wool is.
Yes hit them. You will get into the cycle with them. Veg wise I was always 600-800 ppm (500 scale) strait across the board. Yeah fully saturate to runoff if you are hand feeding when they get light. Veg wise it's pretty similar to peat as you will water when needed. Rockwool, unlike coco, will go pretty light and still be chill from the humidity action in the root zone. You can drown them young almost like soil but the roots will fill the cube pretty quick. You will notice after the first 2-3 waterings.

I saw you were a little worried with the stall. That's normal and will cut down once you kind of get the feel for the watering schedule. My buddy gave me the tip of not fully saturating the cube on transplant and just a little water in around the clone then wait a day or 2 and hit them. Said it cuts the stall quite a bit. Something I never tried but he is on his game.

😃 I try
 
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One thing I’m gonna note here regarding rockwool which is the medium I grow with. Is once you are in flowering it’s important you pay attention to the ppm and ph in and ppm and ph out. While the rockwool ppm and ph can vary inside the cube you must be aware of ppm spike signals. Ideally if your ppm in is higher than the ppm out your plants are taking up nutrients. If you start to see the opposite where ppm out is greater than ppm in then the plant is signaling to you that it’s starting become over fed. I usually don’t let the ppm out exceed 150-200 ppm and then I’ll flush usually with a mix of cal mag and Fulvic/humic acid at around 300 ppm . I’ll run twice the amount of water in the cube than I normally do off a feeding meaning if takes 10 seconds for you to see water come out the bottom of the cube hit them for 20 seconds. And when you feed hit them for an extra few seconds so you get at least 20% runoff flow.

make a new mix the next day and restart this process watching out for the ppm out not to exceed the ppm in by more than 150-200 ppm’s. As far as ph you want the run off ph to be coming out between 6.0-6.5 is usually a safe zone and that can be achieved with a ppm in of 5.5-5.8 ideally you want the ph out to go from 6.0 to 6.5 with your weeks mix so the plant is able to up take all the elements it needs and be balanced.

One thing to note is that for example of it normally takes 10 seconds of watering at the same flow rate you use daily and all of a sudden it’s taking longer like 12-15 seconds to see water come out the bottom of the cube. It’s a signal your plants is starting to use more water than nutrients and it will usually show by ppm out being higher than ppm in. If you can watch this you will never have a nutrient over feeding problem. During the last few weeks of flower the plants will naturally use more water and start to require less nutrients as it’s heading towards the finish line. Best practices is to water them a little more with a lower ppm. Most plants will peak around week 5 at around 1000-1200 ppm out max. And then after that it’s going down hill from there. If you aim for this balancing act you should be fine and never have an over feed problem which can quickly stunt your buds and make them finish early.. Just make sure you give them the proper npk ratios that your strain requires. Ppm(500 scale)

This is how I hit 3-3.5 pounds per light when the environment is dialed in and your canopy space is maximized using double ended bulbs over a 5x5 area per light. If you are using single ended bulbs your target weight over a 4x4 area per light should be 2-2.5 depending on strain. Does require Co2. Without Co2 expect numbers to not be as high. But as far as quality keep the plant balance and happy and you’ll get the most the genetics offer. Last 10 days drop temps make it really cold at dark cycle under 64 and she will frost up even more. Good luck
 
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