rockwool cubes

[tiny]

have been given a lovely Miltoniopsis with 4 flower stems. Unfortunately it is potted in 1cm rockwool cubes with a small layer of fine bark on top. I have never grown an orchid in this type of compost before- how on earth do I know when to water it. I know Miltoniopsis can be difficult but I don't want to kill it off . Any ideas on watering frequency?

[Leisurely]

Use the skewer method.