growdan rockwool blocks

[bearhair]

Recently found some big momma rockwool blocks for 6 bucks each so i bought em planning to just trim them down to 6 x 6 x 6. but now im wondering. ive read that they retain too much moisture at that size. what about 6 x 6 x 8 tall, or 8 x 8 x6 tall... hmm, custom sized rockwool blocks... any input would be appreciated

 

[NORBY]

@420autoflower uses them very well, maybe he could advise.

 

[bearhair]

yeah hopefully. .what do you think @420autoflower ?? will be my 1st try with rock wool..

 

[420autoflower]

yeah hopefully. .what do you think @420autoflower ?? will be my 1st try with rock wool..

Good deal! Would be nice to see more people growing autos with rockwool.
It all depends on how big of a plant you want to grow. I would use the whole 8x8” block to get as much veg and preflower time to be able to work the plant as much as possible before flower to increase yields. If you’re worried about the Big Mama (Grodan 8x8”) holding too much water you can always start your new seedlings in 1.5 Grodan starter plugs then stick the plugs in a 4x4x4” Grodan cube directly after sprouting like I do. The young seedlings grow great in the 4x4” cubes and they don’t take up much space, they buy you an extra 8-12 days before you have to do anything with them, never any risk of transplant shock, no chance of over watering, gives you an extra week of veg/preflower and you can basically place them on top of whatever substrate you wish to grow in.

 

[bearhair]

ok, thanks 420. setting up an auto fertigate and drain to waste system. have been reading up on rockwool and im going to give it a try. no gnats, lol. no cations, like coco. any advice on fertigation frequency for that sized block. is it going to be a lift the block and feel the weight type thing ? should i remove the plastic wrap or maybe a part of it ? sorry @420autoflower so many questions.. more to come. thanks 420

 

[420autoflower]

No worries bro…. always happy to help.
Definitely leave the plastic wrap on and no need to pick up the heavy block to gauge weight. I start with 350 ppm when my seedlings first sprout and feed them twice a day with a turkey baster for the first 10 days. Around day 8 roots are usually coming through the bottom of the 4x4” cube and that’s when I place the cube on whatever medium I choose to grow in and also bump up the nutrient strength to 600-650ppm. I’ll start feeding 3 times day around day 15 then 5 times by day 20. Feeding 5 times a day might be excessive and I know you only need to feed a couple times to get good results.
If you’re just getting your feet wet with rockwool you can simplify things by manually top feeding with the drain to waste method and not deal with having to install a drip system. I’ve grown really nice plants with just hand watering my rockwool/coco a couple times a day with no fancy equipment or large investment.

 

[bearhair]

Guess i might be worrying too much. But, ive read that these big blocks retain a lot of moisture and can cause root issues. Have you ever used them? Thats really all im worried about, block drainage and frequent fertigation to run off. i already have the whole drip system that i used on a coco grow so im just reconfguring it a bit with some flora flex products. Thanks 420

 

[420autoflower]

Guess i might be worrying too much. But, ive read that these big blocks retain a lot of moisture and can cause root issues. Have you ever used them? Thats really all im worried about, block drainage and frequent fertigation to run off. i already have the whole drip system that i used on a coco grow so im just reconfguring it a bit with some flora flex products. Thanks 420

I’m to cheap to buy the Big Mamas but use Grodans 6x6x6” (Hugos’s), Grodan rockwool chunks and slabs. If I want to get a little more veg and pre flower time I’ll add more layers of slab or cut Hugo’s underneath my main block or slab.
This guy uses the Big Mamas and grows really nice plants that are hand watered twice a day and his videos also has step by step instructions on his method from seed to harvest.

 

[bearhair]

Thanks bro, watched a couple of his vids and i definitely have a better understanding. im going to give it a go with these big momma blocks. was reaiiy surprised to see how the water just flowed right thru the blocks when he watered them. thanks again..

 

[bearhair]

found exactly what i was looking for on growdans website. its called precision irrigation.. check it out when you get a chance. lots of good info there..