The myth of Rockwool

Every time I setup for a batch I buy four 6-inch cubes of Rockwool and assure myself I am going to do it this time. HA! Rockwool, the place where plants go to die. Clones just sit for weeks until you decide to end their misery. Seeds pop up and look forward to 12 hour days and a little action but flop and rot at "ground" level. Washed clones started in soil beg to be terminated at the point where just one leaf is left like it was a bad guy escaping "upstairs" in a TV cop show. I have tried every over-lauded method on You Tube and advice from friends, who do not use it for some reason, and I figure, none of them want you to succeed. Drip, flood, steady stream, ends up being tear, toss, and swear A waste of 0.75 per unit and good fertilizer. Aeroponics in expanded clay gonads is effortless. Right amount of water, right PH, right oxygen, moonshine mash for CO2...Win Win. Outside in 45 gal barrels is not all that bad either.

I quit rock-wool because it holds too much water, killed too many plants.
I now start in peat pellets and fill with hydroton.

Good luck

Rock wool is a decent medium. But ONLY for adolescent plants with very vigorous and developed root systems. If you can get your roots to completely CONSUME the cube, you're doing it right. But algae is always a problem. Unless you're covering the tops with like flora flex or something.

Airwalker16 said:

Rock wool is a decent medium. But ONLY for adolescent plants with very vigorous and developed root systems. If you can get your roots to completely CONSUME the cube, you're doing it right. But algae is always a problem. Unless you're covering the tops with like flora flex or something.

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Dats new...I will try to air-layer some giant clones and give it one more try...Thanks.

tannaberton said:

Dats new...I will try to air-layer some giant clones and give it one more try...Thanks.

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I suggest using Aero cloning to get some nice sprouts of roots on your stem and before they get too long, slice a rockwool cube open to fit it down inside, doesn't matter if all the roots go in to one slot. They'll find their way. That cube needs to stay DAMN NEAR DRY too. Like I'd literally put my nutes in a spray bottle and just dampen the whole outside edge and down where you slit it. Seems like once they've been dunked under water, they open up too much and just always stay way too wet.

I don't like rockwool either. crappy medium. I root in rapid rooters.

also rockwool is a place where powdery mildew goes to live. lol

Airwalker16 said:

I suggest using Aero cloning to get some nice sprouts of roots on your stem and before they get too long, slice a rockwool cube open to fit it down inside, doesn't matter if all the roots go in to one slot. They'll find their way. That cube needs to stay DAMN NEAR DRY too. Like I'd literally put my nutes in a spray bottle and just dampen the whole outside edge and down where you slit it. Seems like once they've been dunked under water, they open up too much and just always stay way too wet.

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Thanks

Renfro said:

I don't like rockwool either. crappy medium. I root in rapid rooters.

also rockwool is a place where powdery mildew goes to live. lol

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HA! Thanks...I think soaking them is a bad bad thing but every video says it is necessary. When you squeeze it the oxygen goes somewhere else and you are left with a lump.

tannaberton said:

HA! Thanks...I think soaking them is a bad bad thing but every video says it is necessary. When you squeeze it the oxygen goes somewhere else and you are left with a lump.

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You don't soak rockwool. You also don't squeeze rock wool. It takes some time to get used to, and is not as forgiving as other mediums.

Also water by dipping them, or with a syringe, as they're easy to over-water.

I used Rockwool to start my seeds when I ran NFT rails. Then I'd move them to net pots under Hydroton. It worked fine for what I used it for. I disliked the inflexibility of NFT rails in a small area. I moved to coco and now I use peat pellets to start seeds and that works fine too.

I have a love hate relationship with larger cubes but the little grow cubes have become my favorite medium, with a bit of those expanded clay gonads mixed in (75/25 rw/gonads)

I have always used the Grodan Delta grow cubes in my 6" net lids surrounded with hydroton.-been running RDWC for the past 3 years with that combo. The only thing I can add is that it's important to keep the solution level below the bottom of the cube so it isn't being soaked. I only top feed the cubes until roots drop down and then the cube dries out. No rot, no mildew. Plants thrive.

GBAUTO said:

I have always used the Grodan Delta grow cubes in my 6" net lids surrounded with hydroton.-been running RDWC for the past 3 years with that combo. The only thing I can add is that it's important to keep the solution level below the bottom of the cube so it isn't being soaked. I only top feed the cubes until roots drop down and then the cube dries out. No rot, no mildew. Plants thrive.

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Used to do that. Now the clones bare roots get twisted gently into a singularish piece, then goes straight through a hole in the netpot, fill it with hydroton, and in it goes.

There's just no need for the cube. Once the roots are long enough to be able to pull through the netpot to where the stems at the bottom, they'll pull water through them.

Agreed. The reason I continue to use the blocks is it helps to stabilize the trunk into the netlid. My neighbor runs the same lid with hydroton and her plants need more support compared to what I run into.

Airwalker16 said:

Used to do that. Now the clones bare roots get twisted gently into a singularish piece, then goes straight through a hole in the netpot, fill it with hydroton, and in it goes.

There's just no need for the cube. Once the roots are long enough to be able to pull through the netpot to where the stems at the bottom, they'll pull water through them.

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When I ran clones they went straight into the net pots and Hydroton. Unfortunately I know of no way to start seeds in Hydroton directly.

curious2garden said:

When I ran clones they went straight into the net pots and Hydroton. Unfortunately I know of no way to start seeds in Hydroton directly.

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You sprout in paper towels, then gently transfer it to a clone collar once it's 2" long or so. That way it can grow aeroponically. Never tried it but I'm sure it would work.

I used to use rockwool when I did hydro grows but I only use those clay rocks in net pots now but you do have to stake the plants or use a net...well depending on strain.

Airwalker16 said:

You sprout in paper towels, then gently transfer it to a clone collar once it's 2" long or so. That way it can grow aeroponically. Never tried it but I'm sure it would work.

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Handling immature seedlings can cause damping off from bacteria and fungi from your finger's contaminating them or mechanical damage from breaking the tap root.

curious2garden said:

Handling immature seedlings can cause damping off from bacteria and fungi from your finger's contaminating them or mechanical damage from breaking the tap root.

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While this is a valid concern in practice I don't see it happen. I start in vermiculite and then move them once beyond cotyledon stage. Sometimes I rip them from vermiculite, sometimes I excavate more gently, sometimes I'll dunk into a bucket and snow globe the vermiculite away. I see more damping off from leaving seedlings in too wet or too cold.

Maybe moving sprouts from towels to other mediums this has more concern like as described paper towel to somewhere else prior to coty emerging. Here again haven't experienced this much, they seem to be resilient assuming best practices with hygiene.

CannaBruh said:

While this is a valid concern in practice I don't see it happen. I start in vermiculite and then move them once beyond cotyledon stage. Sometimes I rip them from vermiculite, sometimes I excavate more gently, sometimes I'll dunk into a bucket and snow globe the vermiculite away. I see more damping off from leaving seedlings in too wet or too cold.

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I'm happy you've had good ancedotal experiences. Since I'm no longer in rails I just drop them in peat pellets and get close to 100% germination with low hassle. So whatever works for you.