Seedling just sprouted in rock wool

Discussion in 'Growing Marijuana Indoors' started by Bcgfan101, Jan 20, 2023.

  1. Hi guys!

    I’ve been growing hydro for about a year now. The trickiest phase of the grow for me has been from the moment my seedling sprouts until it reaches veg stage, so seedling stage really. On my last grow, I ran into deficiency problems after they grew a few pairs of true leaves. I understand they don’t need any additional nutrients aside from what the cotyledons provide.

    I’m looking for advice on

    1) after the seedling first sprouts from the rock wool, is it good to leave them within the humidity dome with their tap roots just sitting in the water?

    2) when is the best time to move my seedlings from the humidity dome into my hydro bucket set up?

    3) how do you know the best time to begin providing some nutrients? For my last grow I waited until the leaves showed me slight deficiency and assumed it was time to add my own. They ended up getting worse- I’m wondering if I simply added too much or the plant was wanting more?
    When I begin to add nutrients I start with only 10% of the recommended amounts

    please help me to avoid my mistakes again!

    Attached Files:

  2. First of all consider losing the dome........domes are for clones.
    Rockwool has zero nutrient value, so you need to provide it from day one.
    I grow in coco, which is inert, and I feed the day it sprouts.
    Also, may I suggest using rapid rooters to start your seeds........less headaches.
    Good luck.
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  3. I sprout in 1.5 x 1.5 x1.5 Grodan Mini cubes with the paper on. A soaked cube will stay moist enough for a seed to germinate, But after that, it needs to be watered every 12 hours Full veg strength for me is 720 ppm with silica. I start at half that with no silica for about a week. Then gradually increase. The first thing I do when a seed sprouts is make 1/2 gallon of low strength 6.0- 6.2 feed. I transfer into hydroton with the wrapper removed and then give it it's first feed in the hydroton already. That's the safest place and the hydroton draws water oit of the cube at first and I like that becuse there are no roots to move the water.

    Most advice is from growers with many plants and much of what they do is to save room. It's the same cube whether it is in a big hydroton bucket or a little net pot, Sometimes the tap root will grow down 4 inches in the first 48 hours. I see no benefit to curling in a cube waiting for something to grow in.
  4. I use tap water with rockwool until the first true leaves are crowning then I do a half strength veg feed then on to full strength. I do stack at least 1 more cube once I see roots. Gives some height in the bucket basket.

    Put them in as soon as the stalk is strong enough to handle the rocks around it and she's tall enough.
  5. Great advice all around. Much thanks!
  6. Looks like I’ll be moving them into the buckets tomorrow! Thanks for the help
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  7. I soak in straight tap, and my tap is 8.7. Then I run a qt of distilled with h2o2 through it before I sow the seed, Then nothing until sprout. The main reason I fertilize the first week is because my fertilizer puts my 8.7 tap down to 6.2. Not sure the seedling really needs ir. I planted once in pure perlite and the seedling turned yellow after about 3 days. Then I gave it a shot of high N fertilizer and it greened right up in a matter of hours. So, IDK for scientific sure, Like I say, a lot of advice is from big growers and saving a few days of unneccessary nutes can help the bottom line. I do believe there is somewhere some proof that too strong on a new seedling can stunt it for life. I plant deep in the hydroton and then add more as the stem gets bigger.
  8. Hydro you need to feed as soon as you have a sprout.
    • Agree Agree x 1
  9. Not a fan of rock wool. I've had better luck just putting a sprouted seed directly in a "not too hot" soil where the nutrients are already there. Too much nuts too soon could be worse than none. Once established in soil a bit (1-2 weeks???) you could do whatever with them. IMHO. :confused_2:

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