Ice will not harm your orchid. It will absorb the water better, leaving less sitting water in the bottom of the pot that could cause root rot. Multiple studies show that there is no damage to the plant from the ice temperature, and the precise measurement reduces the risk of overwatering, one of the most common ways to harm an orchid.

Place the ice cubes on top of the potting media under the leaves. (Don’t worry, the ice won’t harm the leaves.) If you can’t fit all the ice into the pot at once, wait until some of it has melted before adding more. Don’t put any ice on the crown of the plant.  

You can certainly use water if you’d like. If you choose water instead of ice, use ¼ cup for a full-sized orchid and 1½ tablespoons for a mini orchid. Make sure to empty any extra water out of the bottom of your decorative pot.

When it comes to ice cubes, size doesn’t matter. So long as the amount you use measures to about ¼ cup of water when melted, your orchid will receive enough hydration.

Misting your orchid with water from a spray bottle doesn’t take the place of watering, but it can be helpful if you notice your orchid needs more humid conditions. If your orchid’s roots are grayish or white, this is a good indicator it needs more humidity. If you decide to mist, make sure your orchid’s leaves have dried by nighttime.

The amount of water your orchid needs can change depending on the season and conditions. Check your roots periodically to make sure the orchid is getting the right amount of water. Roots that are getting enough water are green. Roots that are getting too much water are mushy and brown. Roots that need more water are grayish-white.