Rockwool watering frequency

trademanny

trademanny

Active Member
Hello!

I'm setting up drippers for some 6" Hugos that I'm using for the first time. I've just put my rooted clones in them. What's the simplest way to determine the best watering frequency?

I've read the Grodan docs that discuss moisture gradients and drybacks and smaller, more frequent irrigations during the day and all the crop steering stuff, but this definitely would require a lot more monitoring and automation than I'm willing to invest in right now.

What's the "good enough" rule-of-thumb you guys are all using to set your schedule? :confused:
 
Growoolit

Growoolit

Well-Known Member
About 3 times a day to 10% runoff.
If you need to water in the night cycle, the plant's too big for the cube/ block.
Maybe add a slab. They can be reused until they collapse structurally.
I'm a long-term user and fan of rockwool.
 
trademanny

trademanny

Active Member
Thank you! I just watered for the first time yesterday since moving them into the big blocks last weekend.

I think I may have a ph problem (leaves getting crinkled and odd) on a couple plants. Apparently Grodan made some changes to their blocks where they don't need to be soaked for a long time to bring the pH down -- but I have the older silver-wrapped blocks that I think still required the longer soak. I drew some solution from the bottom of the block and the pH was 6.3 on these problem plants.

Any thoughts?
 
J. Rocket

J. Rocket

Well-Known Member
dont worry about the block itself. if you gave it a properly ph'd soak/rinse its not an issue. I've not needed more than an hour or so.
do stay away from the crop steering stuff.
drip irrigate to runoff. I run once to three times a day depending on age. usual peak is 7 minutes 2x a day during flower.
lets see some plant pictures!
 
trademanny

trademanny

Active Member
J. Rocket said:
do stay away from the crop steering stuff.
drip irrigate to runoff. I run once to three times a day depending on age. usual peak is 7 minutes 2x a day during flower.
Click to expand...
Should I be seeking to achieve runoff on every irrigation, or just by the end of the day after all irrigations?

Thx!
 
N

nxsov180db

Well-Known Member
trademanny said:
Should I be seeking to achieve runoff on every irrigation, or just by the end of the day after all irrigations?

Thx!
Click to expand...
In veg I like to see runoff during each irrigation, but I only irrigate 1-2x per day in veg. In bloom you want to start watering around 2 hours after light on and stop 2 hours before lights out, and you don't want runoff on the first watering, you don't want to see runoff until the last 1/3 to 1/2 of the watering schedule. The ph rises even in the new blocks, I transplant my clones into fresh blocks and when I water a few days later the runoff ph is 6.5-7, and that's with a 5.0-5.5ph soak and 5.5ph watering. But that's what happens when they sit.. The transplanted clones don't seem to mind. Having 6.3ph as runoff shouldn't be bad at all. Whats the feed ph?
 
N

nxsov180db

Well-Known Member
Oh and you want to water more times per day with shorter on times vs less times per day with longer on times. So in other words its better to water 6 times a day with irrigation running for 1 minute vs 3 times per day with irrigation running for 2 minutes. So ideally you would use lower GPH emitters vs larger. 6" blocks you'd want to use 2 per block, or 4 if you have the patience. What are you using for Rockwool caps and emitters?
 
trademanny

trademanny

Active Member
nxsov180db said:
Oh and you want to water more times per day with shorter on times vs less times per day with longer on times. So in other words its better to water 6 times a day with irrigation running for 1 minute vs 3 times per day with irrigation running for 2 minutes. So ideally you would use lower GPH emitters vs larger. 6" blocks you'd want to use 2 per block, or 4 if you have the patience. What are you using for Rockwool caps and emitters?
Click to expand...
I've got the floracaps on there. No emitters, just straight tubing from my drip manifold (tuned for equal flow rates across all). Feed pH is at 5.8. I do only have one hose to each cap, but it's got a T on the end at least for distribution.

Here's my issue -- this is my first Rockwool run. I've done DWC before with great results, but never RW. I'm terrified of overwatering (ala soil) so I'm struggling to figure what is best. I did one manual irrigation a few days ago once the blocks lost about 20-30% of their starting weight, but that's been it so far. Things look ok, with the exception of a couple plants with wrinkled crinkly new growth. I was attributing it to pH, but maybe not, maybe an irrigation/oxygen issue?
 
J. Rocket

J. Rocket

Well-Known Member
relax. lots of stuff is wrinkly.
first rule is no freaking out. :peace:
good on the watering based on 20-30 weight loss.
if you can track weight early on that helps you understand needs.
bone dry 6x block is approx. 250 gm, well soaked is 2000 gm.
once the plant has established itself I water to run-off every time.
water to run-off or your leaving spent nutrients the plant doesnt want in the block.
 
ProPheT 216

ProPheT 216

Well-Known Member
trademanny said:
I've got the floracaps on there. No emitters, just straight tubing from my drip manifold (tuned for equal flow rates across all). Feed pH is at 5.8. I do only have one hose to each cap, but it's got a T on the end at least for distribution.

Here's my issue -- this is my first Rockwool run. I've done DWC before with great results, but never RW. I'm terrified of overwatering (ala soil) so I'm struggling to figure what is best. I did one manual irrigation a few days ago once the blocks lost about 20-30% of their starting weight, but that's been it so far. Things look ok, with the exception of a couple plants with wrinkled crinkly new growth. I was attributing it to pH, but maybe not, maybe an irrigation/oxygen issue?
Click to expand...
Lots of good info here. Me personally I combine both methods. I hatch seeds and put clones into rw. Then Add more cubes as necessary. Then about 2 weeks before I want to flower that plant ill put it rw and all in a dwc 5 gal bucket and let the roots get going. Then into flower as a dwc grow.
 
lusidghost

lusidghost

Well-Known Member
ProPheT 216 said:
Didn't know you were a rw guy :clap:
Click to expand...
I've flipped back and forth between coco and rockwool a few times, but I think I'm staying with RW from here on out. After this run I'm going to start using RW fill chunks instead of slabs. I cut about 8" off of the slabs in my current grow because they were staying too moist. I want a cycle of water / air / water / air as frequently as possible. I'm also going to be using mist emitters in a little tray box that I created. I have one prototype going now and it's doing really well.
 
ProPheT 216

ProPheT 216

Well-Known Member
Coco I don't like the bugs. I like the elimination of all pests using rw and dwc. I though about using chunks, but even that is damn pricy vs dwc
 
lusidghost

lusidghost

Well-Known Member
ProPheT 216 said:
Do u like the white wrapped cubes or the silver cubes? White seems to dry out faster @lusidghost
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I don't think I've ever tried white wrapped cubes. I usually use Grodan's 4x2 cubes, whatever they are called. 4x4 cubes stayed too moist for seedlings, so I would have to be more careful until the roots caught up.
 
J. Rocket

J. Rocket

Well-Known Member
white cubes are called "pargro quick drain". still a grodan product.
from my use of the 6x I'd say a slightly better moisture gradient/draining but still holds about a half gallon soaked.
20220808_093742.jpg
 
trademanny

trademanny

Active Member
J. Rocket said:
relax. lots of stuff is wrinkly.
first rule is no freaking out. :peace:
good on the watering based on 20-30 weight loss.
if you can track weight early on that helps you understand needs.
bone dry 6x block is approx. 250 gm, well soaked is 2000 gm.
once the plant has established itself I water to run-off every time.
water to run-off or your leaving spent nutrients the plant doesnt want in the block.
Click to expand...
Should I be waiting until a similar dryback (20-30) between each irrigation, or is that only for when first establishing the block and fully saturating it?

Thank you for the help!
 
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