Know that these plants can survive for weeks without any water. This is because they have water storage capacity that can conserve water for a long time. so it will conserve enough water to stay alive even if they are in the wild.
When they are fully grown, water them less since they can survive without water compared to when they were small. You need to give them time to get used to your climate and growing conditions before watering them. If they are indoors, keep them in indirect light and water them less frequently. Avoid using cold water during the winter and months, and you might be overwatering when the plants are located indoors. Give this a rest, especially during the winter and fall.
When they are outdoors, refrain from watering too much. They should be able to get enough humidity, moisture, and rainfall that will keep them alive. Only water when you see that their leaves are becoming droopy and yellowish. Always lean on the side of underwatering as the
Hedge cactus is very tolerant to dry conditions. They don't like wet feet and might wilt when you water them too much.