Watering Spud?

Cacti prefer to have lots of light and relatively little water. Because they store so much water in their bodies, the soil can be bone dry for a year or more, before they start to shrivel. This means they can stay in a dark spot for an extended period.
Since they grow slowly, they are accustomed to manufacturing food slowly. In a dark spot, they grow imperceptibly, and thus retain their original appearance. The large, barrel-types can easily last 2 years or more in the dark--providing they are not watered. Even in bright window light, a 2" tall Barrel Cactus will need no more than 2 waterings a year. Cacti are like the rest of the tropicals in showing overwintering---their surface color gets a paler mottled green.
Most Cacti need plenty of light to flower (over 1000 footcandles of light), but the Crown of Thorns ( Euphorbia splendens), will produce a few flowers in light as low as 200 fc. The tiny, blood-red blooms contrast refreshingly with the tiny, oval leaves. A Crown of Thorns needs more water than the more traditionally-shaped Cacti. In bright window light (500 fc+), you may have to water every 2 or 3 weeks.
Like Succulents, you water Cacti by feeling the flesh for moisture content. Wait until the skin is wrinkled and soft before pouring the water. A single dose of water, before the plant is ready to accept it, often spells doom indoors.
Yip

Here where it is very very hot with little rain, the cacti live under bushes for the shade and get what water they get. They live pretty much on the morning dew so they need very little water and lots of light.

I have had cactus plants for over forty years. They were a in flower pots and were watered once a week. If it got very hot outside I watered them a little about every three days.
I don't have those plants anymore because they got so big and one day I fell into them getting hurt real bad so I shoved them into the trash barrel and the trash truck picked them up and took them away. I won't keep a plant that bites no matter how long I have had it!

Cacti don't need much water. They're succulents, so they retain water. Water him about every two weeks or even less. Don't water much at a time, either.

Look it up on internet.

If it's a cactus with a round fleshy stem, you should wait until the compost has completely dried out, then give it a good soaking. If you underwater, the stem will start to shrivel, but it will recover if you soak it. If you overwater, it will die.

many thrive on dry conditions and the take in the moisture from the air