How often to water seedling in rockwool and when to transplant

C

Crescendo

Member
Hello everyone! I’m a first timer grower so really wish to get some insights from you.
I just planted seeds in Rockwool cubes and I’m wondering how often I should be watering them as I started already getting some seeds sprouted after 3 days under the humidity dome which I now removed. I soaked the cubes before for 24 hours and all went smoothly so far a couple of seeds still taking some time to germinate but on their way. I also placed all of them under a 36W 6500K lights a few inches away so won’t stretch too much. For the ones I germinated, there are some leaves coming out but I’m not sure how often and how to water them and when to transplant.

1) For watering: Should I spray ph-ed water on the cubes or pour water on the tray and what criteria to decide how much? My rockwool cubes are still fairly humid so I wouldn’t be tempted to soak them again but cannot find any specific criteria to take that decision. I also wish to avoid them to dry too much.

2) For transplanting: I also want to transplant the cubes into a Wilma system that will have four pots of 11 litres. After how many days on average or what I need to observe before doing that? This step will make my life easier for feeding but before then I just don’t want to mess up till my cubes are on the tray

Thanks for your tip :)
 
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Airwalker16

Airwalker16

Well-Known Member
Rockwool is always hard to start seeds in. They stay too wet. You don't need to water them at all. At least until you can feel the outside of the cube actually BONE DRY. Then you can spray a few mistings to dampen it again. But other than that, this is why people fail so often with rockwool. OverWatering. Just LEAVE EM ALONE!
 
C

Crescendo

Member
Airwalker16 said:
Rockwool is always hard to start seeds in. They stay too wet. You don't need to water them at all. At least until you can feel the outside of the cube actually BONE DRY. Then you can spray a few mistings to dampen it again. But other than that, this is why people fail so often with rockwool. OverWatering. Just LEAVE EM ALONE!
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That’s great to know... and when would it be a good time to transplant them into a 11 litres vase filled with clay pebbles that I’ll use in my hydro system (drip system)? What would be the key signs that indicate they are ready to be transplanted? Thanks!
 
C

Crescendo

Member
Airwalker16 said:
When you're cube is completely packed with roots and plants decent sized.
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Thanks for that, what do you mean for decent size? How many nodes? I also noticed by putting the fan on (low strength) close to the seedlings, the rockwool is drying real fast and the growth has picked up a little bit faster.
 
Airwalker16

Airwalker16

Well-Known Member
Crescendo said:
Thanks for that, what do you mean for decent size? How many nodes? I also noticed by putting the fan on (low strength) close to the seedlings, the rockwool is drying real fast and the growth has picked up a little bit faster.
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When your stems a good 3/16" thick or so. When you're cubes full of roots,you'll know. Make sure it's in a tray so they can actually root bound the cube and not just die by air pruning.
 
C

Crescendo

Member
Airwalker16 said:
When your stems a good 3/16" thick or so. When you're cubes full of roots,you'll know. Make sure it's in a tray so they can actually root bound the cube and not just die by air pruning.
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This is such a good tip! I am getting a seedling tray on my way, for now they are just standing on the tray I used to germinate it. This is an open container and does not have separator between rockwools. I have also kept the plastic wrap around the rockwool, is that necessary or should I take it off to allow roots around as well. Thanks
 
Airwalker16

Airwalker16

Well-Known Member
Crescendo said:
This is such a good tip! I am getting a seedling tray on my way, for now they are just standing on the tray I used to germinate it. This is an open container and does not have separator between rockwools. I have also kept the plastic wrap around the rockwool, is that necessary or should I take it off to allow roots around as well. Thanks
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Taking off the plastic is exactly opposite of what I told ya. Keep it ON. That's a barrier and will keep your roots tight.
Are there visible roots along the bottom and sides yet? How big is it? Pics?
 
2Hearts

2Hearts

Well-Known Member
To be frank you want to water plugs every 24 hours wether rock peat flexishit coco paper scissors.

If they aint drying out by the end of the day or next cycle they arent in the right enviroment.

Overwatering is being wet too long, dont put rockwool in that type of enviroment where a tiny cube take three days to dry, commercially thats bad.
 
C

Crescendo

Member
2Hearts said:
To be frank you want to water plugs every 24 hours wether rock peat flexishit coco paper scissors.

If they aint drying out by the end of the day or next cycle they arent in the right enviroment.

Overwatering is being wet too long, dont put rockwool in that type of enviroment where a tiny cube take three days to dry, commercially thats bad.
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For the first days it took quite a long time for the cube to dry but now, especially with the use of the fan, the cubes are drying much more quickly and I am watering them (very carefully) at least once a day. I found the use of the nebuliser very useful at this stage.
 
C

Crescendo

Member
Airwalker16 said:
Taking off the plastic is exactly opposite of what I told ya. Keep it ON. That's a barrier and will keep your roots tight.
Are there visible roots along the bottom and sides yet? How big is it? Pics?
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Point taken. I will keep it the wrap. Roots are visible from the bottom, 5-7 cm stem and first couple of leaves seem growing well. Posted the pic below
 

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Airwalker16

Airwalker16

Well-Known Member
Crescendo said:
Point taken. I will keep it the wrap. Roots are visible from the bottom, 5-7 cm stem and first couple of leaves seem growing well. Posted the pic below
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As fuck you put them in bigger cubes. Now you're gonna be waiting even longer. Lok
 
Airwalker16

Airwalker16

Well-Known Member
Crescendo said:
No sure I got that. Do you mean these cubes are too big? They are the smallest ones I could find: 4 cm square...
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The original small 1.5" square was enough to get your roots blown out. Now you gotta wait for then to go all the way through the bigger cube, reach the bottom and the sides and fill it out.
 
C

Crescendo

Member
Airwalker16 said:
The original small 1.5" square was enough to get your roots blown out. Now you gotta wait for then to go all the way through the bigger cube, reach the bottom and the sides and fill it out.
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Do I need to get a bigger cube? I was thinking to just plant this one after it gets a bit more developed into the medium I chose (clay pellet) in a bigger vase (11 liter). Did not want to keep going with the rock wool. What's your take on this?
 
Airwalker16

Airwalker16

Well-Known Member
Crescendo said:
Do I need to get a bigger cube? I was thinking to just plant this one after it gets a bit more developed into the medium I chose (clay pellet) in a bigger vase (11 liter). Did not want to keep going with the rock wool. What's your take on this?
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How could you possibly get the idea that I suggested getting an even BIGGER cube from what I said? Is English not your first language?
 
C

Crescendo

Member
Airwalker16 said:
Oh damn your seedlings are just that small. I thought they were in 4" cubes my bad
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They are growing quite slowly, I planted them 8 days ago and did not go past 2 leaves. They are 2 feet away from a 300W led light (in veg mode so blue spectrum) and I am watering them with ph 5.8-6 EC below 0.5 only when I feel the cube dried (once every 1-2 days), with just a little root booster addition. I wonder if I am overthinking it and just need to wait up.
 
MrGreenFingers99

MrGreenFingers99

Well-Known Member
Get it in your system, I dont understand the point of rooting a cube, it's going to root in your system anyway, the quicker roots are in the water the quicker they grow and the less chance of messing up trying to water a tiny rockwool cube
 
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