Watering your outdoor cacti. Yes, they need it!
Watering. This is the most asked question that we get at the nursery. Let me first say that every situation is different. If you are having success don’t listen to me.
The rules that I have always had success with are:
Water slow and deep with in ground cacti, this seems to really keep them from stressing so much and grow more evenly. This is also referred to as ‘deep soaking’. Deep soak is a slow, but steady, drip from a garden hose over a two to six hour period. The size of plant determines the duration.
Watering in Pots, I water twice. First, I water several pots at a time (about a 4 foot section) enough to fill the pots. Then I go back and water again so this time the water is drawn deep and evenly into the pot and soil.
Daily temps are a factor. In warmer temperatures, more watering is required. In cooler temperatures, less watering is required. See ‘Seasonal Watering Tips‘ below for more information.
Size of plant counts. The larger and more established the plant is the less often you will have to water. It has a larger “storage tank” and can go longer between watering. For example a large Saguaro may never need watering where a tiny 1 gallon gold barrel could take as much as once a week watering.
Don’t water newly planted cactus. If you are repotting or adding to your landscape the same rules apply, plant dry and wait to water. Watering all depends on the weather, the cooler it is the longer you wait for that first drink. You should usually wait at least a week, this gives the succulent roots time to heal before being exposed to water. Only water again when the soil is dry at the roots, each situation is different, no two are alike.
Summer is when the daytime temperature is 90° or more for three consecutive days.
Deep soak is a slow, but steady, drip from a garden hose over a two to six hour period. The size of plant determines the duration.
Newly planted cacti: (except Saguaros)
If the daytime temperature is OVER 90°, wait one week before first watering. If the daytime temperature is UNDER 90°, wait two weeks before first watering.
Agaves should be watered immediately following planting when the temperature is over 90°. If the temperature is cooler than 90°, wait longer to water.
Saguaros should NEVER be watered. There are exceptions to this rule also which require common sense. If we are in a period of drought, then you might have to water if your saguaro is obviously shrinking in size and the area is very dry. This is not Carte Blanc to hose the plant off whenever it occurs to you, do it for a reason. I have never understood the term ‘Common Sense’ as it seems to be very uncommon. And no, your next door neighbor is not the best source of knowledge about your landscape plants. If the nurserymen advised a specific pattern to follow, the guy next door from New Jersy may not be a better source of advice! An expert is a guy with a loud voice a long way from home.
First Summer:(except Saguaros)
Native and non-native cacti should get a deep soak every two weeks when the temperature is OVER 90°. In extreme heat, Agaves may be watered once a week, but this is usually too often. Plants in pots in full sun are a special case and they have to be checked for moisture very frequently as their roots are exposed to exptremely hot temperatures every day. Push an unfinished wooden dowel or wooden paint stir stick into the pot to the bottom and check for moisture after waiting 15 or 20 minutes. The key is to have an unfinished piece of wood so it can absorb moisture. You will soon learn what pattern you should follow to keep your plants alive.
First Winter: (except Saguaros)
If the daytime temperature is BELOW 90°, native and non-native cacti should get a deep soak once a month, ONLY if rainfall is less than 1 inch in a 30-day period. If the rainfall is more than 1 inch in a 30-day period, do not water.
Second Summer: (except Saguaros)
If the daytime temperature is OVER 90°, native cacti should get a deep soak once a month. Non-native cacti should get a deep soak two times per month.
Second Winter: (except Saguaros)
Native cacti should not be watered, even in the absence of winter rains. Non-native cacti should get a deep soak one time per month.
Third Summer and There After: (except Saguaros)
Native cacti should be naturalized and need no further watering. Non-native cacti should also be naturalized and not need watering. But, in extreme heat and absence of rainfall, a deep soak is recommended one time per month.