Sprouting in Rockwool: how wet should I get?

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

InuYasha

Well-Known Member
Joined
Jun 9, 2008
Messages
46
Reaction score
11
I'm just getting ready to germinate my first set of seeds. I am going to use the much loved paper-towel method, and then after a root apears place the cracked seeds (with their small root) into some rockwool that I've been soaking and Ph adjusting.

When I place the germinated seeds into the rockwook cubes, should the rockwool be sitting in a tray of water or should I just water it a few times a day and let the water drain away? Also, should I be using plain (Ph adjusted) water or a dilute nutrient solution? This is my first foray into hydroponics, so any advice / corrections would be great.
 
No nutes...Just pd'd water, I put the cubes in a tray with about 1/4" of h20, and covered with a dome(optional) untill leaves show.. goodluck.
 
:yeahthat:

What size setup are you working with?

Let us know how it goes, good luck and GREEN MJOJ!
 
Rockwool needs to be soaked in water that is acidic before using--around 5.5, I think.
 
Thanks. I've placed the beans in the paper-towel method untill they show a root tip, then I'll be moving them to the rockwool.

I'm trying to grow 10-12 CH9 Jack Fems in 2 Gen. Hydro Rainforest 66's in a 2x4x7 tent. Airflow in the tent is provided by 2 6" inline duct fans that run 15min on / 45 off around the clock. Vegging under a 600W MH Growbright Conversion. Flowering under a 600W Growbright HPS both in an air-cooled Euro reflector with two 250 CFM inline duct fans fans that sync when the lamps are on. I plan on using GH Flora Series nutes (that came with the Rainforests) and perhaps moving to the 2 or 3 part Advanced Nutrients at some point in time.

I'm sort of learning as a I go, but I have some bio / chem background, lived in Holland and I've been reading boards anxiously learning as much as I can.

Any advise / suggestions about my set-up, please let me know.
 
Keep us posted on your results. I am having problem with the paper towel method or bad seeds.
 
9/10 of my CH9 Jack Fem seeds have sprouted 1/2 - 1" roots now and I've transplanted them into the soaked / ph adjusted rockwool (in a humidi-dome). Now I'm just waiting for the cotyledon leaves to emerge before I turn on the lighting. At what point should I start them on nutes? When should I should I plant them in the rainforest?

Thanks
 
Once the "seedleaves" begin to yellow the plant "needs" supplimental nutes.
 
the babies will use up all the energy in the seed pretty quickly, you will need to give 1/4 strength nutes by the time you get proper leaves growing, then start your veg routine when you have 3 or4 sets of leaves
remember to go easy on nutes at first
good luck
 
And they don't need to be soaking wet either, you are just inviting root rot. Just dunk the cubes, squeeze out the excess and put your seed in it. Check them daily and make sure they are moist. Not wet, but moist. Big difference. This holds true when cloning as well.
 
Thanks. I did have them standing in a bit (1/4") of H20, but with my high temps (almost 90F) I think that puts me at risk for root rot or some sort of fungus. I'm now watering them a few times a day, squeezing them a bit and placing them back in a dry, slotted tray. I also got some Hydrogaurd today as a preventative measure.

I always heard that it was "impossible" to over-water rockwool. Then again, I'm a firm believer in the old adage that nothing is impossible.

I'm a bit fearful of drying them out. The temp is high and I'm running a 600W MH-conversion lamps in the 2x4x7 tent.
 
Sounds like you need to work on your ventilation. Try to get those temps down it will really help. Other than that you sound like you know what you're doing. Keep us up to date, good luck.
 
You say the best way to grem seeds in rockwool is to soak the rockwool fist then squeeze out excess water. then place seeds in and leave moist and not wet. How low will this take for a seed to pop and sprout.I've been having real problems germinatting and now i'm nervous to try with the expensive ones. need a sure fire way. please help.
 
Don't know if this is the 'best' way, but I got 9 pretty healthy plants from 10 seeds.

I started my first hydro beans about a month ago. Everyone on this forum helped alot.

I soaked my rockwool in ph corrected distilled water overnight to minimize the high ph effect of rockwool. I had the seeds soaking using the paper-towel method and (very carefully) transplanted the seeds once I saw a bit of root tip. Despite putting them in upside down, the seedlings are now healthy plants very well now. I used ph corrected distilled to water the seedlings until water just began seeping out the bottom (maybe a few tsp) and then squeezed them a bit until I could hold them with no dripping. I did this a few times / day (whenever they looked like some of the rockwool was getting dry). I kept them until about 3 sets of leaves and then transplanted them to my planters.
 
Does rockwool normally have drastic pH levels. I've never had a problem...?
 
Yes, rockwool has a high pH and should be soaked in water that is about 5.5

If seeds are not germinating, make sure that your environment is warm enough and that your ph and ppm are within tolerances. Also, old seed stock, IMO, is harder to germ than fresh seed stock.
 
personally i do not like rockwool..i gave 2 of the big trays of it away.nothing but rapid rooters for me.i know its a preference thing.i have had such good results with the RR cubes,for seeds and clones.
 
andy52 said:
personally i do not like rockwool..i gave 2 of the big trays of it away.nothing but rapid rooters for me.i know its a preference thing.i have had such good results with the RR cubes,for seeds and clones.

Rapid Rooter seem like the best method, but I didn't get them because I was concerned about contamination of the reservoir due to the organic material falling apart or being broken down when the pot would be flooded in a ebb and flow system for example. I guess with DWC they aren't getting wet from being flooded so it doesn't matter? Do you think it would work with an ebb and flow system?
 

Latest posts

Back
Top