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Originally Posted by northerntights Tell that to the pounds of rockwool I have gone through in the past two months. |
If you're getting slow rooting in rockwool cubes, they're being kept too wet. Think damp, not wet or saturated. No air in the cube = no roots.
Shake all excess water out of the cube with a sharp snap of the wrist before plugging the cutting in. You can get the watering right by using a small set of scales. Dry 40mm cubes weigh 5.0 grams. A
damp 40mm cube (before the cutting is plugged in) should weigh 25-30g. If it's any heavier, it's too wet.
Water rockwool cubes by dipping only the corner into pH adjusted water as shown for no more than 2-3 secs.
Heat mats go a long way to speeding things up. Proper horticultural mats are the way to go- don't try to use a heating pad for people.
Rockwool is a bit alkaline (pH higher than 7, more like 8.5). Soak cubes for 24 hours in fresh water, pH adjusted to about 5.0 before you put the cubes in.