Cacti require timely and effective watering to thrive. Knowing when exactly to give your cacti their water is essential in keeping them healthy.
Generally speaking, most cacti should get watered once a week during the spring, summer, and fall seasons; while they need semi-regularly watering during winter. The frequency of watering should increase with the temperatures
When you do water your cactus, be sure to use lukewarm water at room temperature; tap or distilled water work well, but don’t use cold/chilled water straight from the fridge—it could shock it!
Always check if the soil is completely dry before starting to irrigate and stop when you see that the water starts coming out from below the pot or just after that happens (this is a sign that your plant has sufficient moisture).
You can also feel how heavy your pot is; if it’s particularly light, then this means that it needs hydration. Then depending on how much light/heat your cactus is receiving, adjust its portion size accordingly. Generally less in cooler weather; otherwise, its roots may rot due to too much moisture accumulation. Keep an eye out for any signs of overwatering, too, such as dried leaves, as this could cause root rot.
Finally, remember to never overfill – no more than ¼ inch of standing water – runoff will reduce the oxygen concentration in soil, which can stunt the growth and development of roots which are needed for better hydration absorption.