What pH should my feed be for a straight rockwool grow?

[88WW]

my White Widows are still in the paper towel. but I leave them in the 1.5" cubes for a week or so, what PH should I aim for on my nutrient feed?

I am using emerald harvest 3 part and thinking of going 200-300ppm.

once the roots are filled in the 1.5" cubes I will be putting them into the 4" blocks.

 

[zeroday]

What's your long term plan? Are you going hydroponics? Or some other medium.

To answer your question, I've always pretreated the cubes. Soaking them for a day in 5.5ph water, then put 520ppm veg solution at 6.0ph in them, drain away excess water, and then drop in seeds. Not sure how you are planning to do it.

 

[zeroday]

Also,

 

[88WW]

it will be a hand pour full rockwool grow.

paper towel gerimnation
1.5" cube -> 4" block -> stack the 4" on top of a 8"big momma block for the final home.

4 plant set up in a 4x4x8 gorilla tent.

my research on the internet shows the new grodan rockwool dont need to be soaked in 5.5 because they changed some of the ingredients in the rockwool.

so I am not sure who to beleive.

for runoff is 15% ok or should it be 30%

 

[zeroday]

Sorry man, I've never gone all the way self pour. Lets see if anyone else can chime in.

 

[DaddyKush]

Well, rockwool is naturally very alkaline. I always soak mine in water pH'ed to 5.0 - 5.5 for a minimum of 2 hours to make it less alcaline, and then also pH adjust all further waterings to about 5.5. I do this until they root and then they go into soil and I don't need to adjust the pH of the water beyond that point. Never gone all the way to harvest in rockwool so I can't tell you more than that.

 

[DaddyKush]

my research on the internet shows the new grodan rockwool dont need to be soaked in 5.5 because they changed some of the ingredients in the rockwool.

I just checked Grodan's website and they do indeed recommend you pH adjust their cubes.