how to tell if rockwool has enough water ..

ok it's hard to tell when rockwool needs water or has too much water for seedlings.

i figured it would seems simpler to weigh the cubes to tell if they need water and less chance of error for me.

i used 2" inch cubes. dry they are 8 grams and after watered, 48 grams.

the surface of the cubes seems dry but there is enough water inside.

my question to some long-time rockwool users: when should i re-water them, when they're about 20 grams?
also does 45-50 grams seems like a lot or too little water for a 2 inch cube?

I've never weighed my cubes before but your best bet is to just water when they feel light. As long as you have decent drainage you can water them a few times a day. Then it's just a matter of wasted nutrients and time unless you have a recycling system with pumps on timers. Trust me it's way more of an art then a science.

smokeitd said:

ok it's hard to tell when rockwool needs water or has too much water for seedlings.

i figured it would seems simpler to weigh the cubes to tell if they need water and less chance of error for me.

i used 2" inch cubes. dry they are 8 grams and after watered, 48 grams.

the surface of the cubes seems dry but there is enough water inside.

my question to some long-time rockwool users: when should i re-water them, when they're about 20 grams?
also does 45-50 grams seems like a lot or too little water for a 2 inch cube?

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bump. I'd like to see this question answered by the experts.

I think I must have been high when I posted my first response on here. Ignore my advice it would actually lead to over watering. What you need to do is take the cube and water it. Then shake it till all the excess is out. Weigh it after shaking and that is the target you want to go for. I personally just do it by feel but for the weight you want to keep it at water then shake. Also the cubes can seem pretty dry but still be moist enough to keep the plants healthy. Also if you really want to figure out the weight for watering let the plant dry out and check it often until you see it beginning to wilt. Then you can know what the minimum weight is. Eventually though you should get a feel for it because the weight of the plant will mess you up and if you have more than one or two plants it would suck having to weigh them all the time.

greenstar said:

bump. I'd like to see this question answered by the experts.

Click to expand...

Hey iv been growing with rockwool for years and you just have too experiment, start watering a little then if they start looking a bit tired just up the water you are giving them iv never had trouble with it. i water each plant once a day about a litre for a 300ml pot full of rockwool a little less when there small and a little more when they flowering just make sure to flush with water a least once a week ti works for me! cheers.