Cacti are resilient succulent plants that are adapted to thrive in arid environments. While they don’t need frequent watering like other houseplants, knowing when to water a cactus is still important for keeping it healthy. Here are some tips on how to tell when your cactus needs a drink.
Look for signs of shriveling
The most obvious sign that a cactus needs water is visible shriveling or deflating of its body. As the cactus goes longer without water, it will start to look deflated and its flesh will lose firmness and appear wrinkled or puckered. The shriveling happens as the cactus loses moisture and starts to dry out. If you notice these signs, it’s time to give your cactus a good, thorough watering.
Pay attention to soil dryness
In addition to the look of the cactus itself, also pay attention to the moisture level in the soil. Use your finger to touch the top inch or two of soil. If it is completely dry and crumbly, that’s a sign the cactus is ready for more water. The soil should be allowed to dry out in between waterings, but it shouldn’t get to the point where it is totally dried out.
Watch for drooping
Some cactus varieties will start to droop or lose their firm, upright structure when they need water. Columnar cacti in particular can start to bend and lose their shapely form when overly dehydrated. Other types of cacti may start to take on a more limp, flexible texture rather than staying rigid. Subtle drooping is a sign to water soon.
Consider time between waterings
Pay attention to how long it has been since your cactus was last watered. During the growing season in spring and summer, most cacti need water every 2-3 weeks. In the fall and winter when growth has slowed, scale back to watering every 3-4 weeks. If it has been longer than the normal recommended time between waterings, err on the side of giving your cactus a drink.
Watch for changes in appearance
Learn what is normal for your cactus in terms of its shape, firmness, and coloring. Subtle changes like loss of sheen, dulling of spines and flattening of ridges can hint that it’s thirsty. The most obvious change is if sections start to dimple or take on a deflated, shriveled look. Get to know your cactus when it’s plump and happy so you recognize slight variations.
Consider sunlight and temperature
Environmental factors like increased sunlight and warmth will cause a cactus to use up soil moisture more quickly. Keep an eye on the weather and where your cactus is situated. Hot, dry spells or moving it into more direct sunlight could mean it needs more frequent watering. Extreme heat can make the soil dry out very rapidly.
Know the species
Some cactus species are naturally more prone to wrinkling or shriveling between waterings. Become familiar with what is normal for your specific variety. Types like the fishhook barrel cactus and fruit-producing prickly pear are more likely to show visible changes in appearance when they get thirsty.
Check new plants frequently
If you’ve just brought home a new cactus, keep a very close eye on it for the first few weeks and months. Newly transplanted cacti have an increased risk of drying out before their roots become well established. Check soil moisture frequently and watch for any early signs of wrinkling.
Consider repotting
Faster than normal moisture loss can be a sign your cactus is becoming rootbound in its pot. If it seems to need water way ahead of schedule, inspect the roots. Very densely packed and circling roots prevent proper hydration. Consider repotting into a larger container.
Use well-draining soil
Always use a specialized cactus and succulent soil mix for your potted cacti. These mixes contain ingredients like gravel, sand and perlite to provide fast drainage. Regular potting soil will hold too much moisture and lead to root rot. Proper soil supports the need for infrequent deep watering.
Follow a deep watering method
When you do water, give your cactus a thorough soaking until water runs out the bottom drainage holes. Avoid frequent shallow sprinklings, which will lead to shallow root growth. Deep weekly or biweekly soakings are better than light daily waterings.
Consider a gravel tray
Use a drainage tray filled with gravel and a little water to increase humidity and give your cactus more evaporation moisture. As the water evaporates from the tray, it creates a humid microclimate around the cactus that can extend the time between deep waterings.
Know when to water seasonal cacti
Some cacti like Christmas and Easter cacti are more seasonal in their growth and water needs. They require more moisture during spring and summer when actively growing. Back off on water during their fall and winter rest periods. Their water needs shift based on seasonal conditions and growth.
Inspect the roots
If you suspect your cactus is being under or overwatered, carefully remove it from its pot and inspect the roots. Healthy cactus roots are plump and firm. Mushy, rotten roots mean overwatering. Dry, shriveled roots indicate underwatering. Adjust your watering practices accordingly.
Take cues from natural growth
Most cacti have adapted to go extended periods without rainfall in their native desert environments. Time your waterings around the cactus’s natural growing period, which is during spring and summer. This mimics its seasonal water needs and winter dormancy in the desert.
Talk to more experienced growers
Chat with staff at your local nursery or other more seasoned cactus aficionados. Ask questions about your specific variety and when they recommend watering based on pot size, soil, time of year, sunlight exposure and other factors.
Conclusion
Determining when a cactus needs that next drink takes some attentiveness and getting to know your plant. But by watching for visual cues like wrinkling and drooping, checking soil moisture, being aware of environment, and understanding the species’ needs, you can keep your cactus hydrated and happy.