More cacti and succulents are killed by over watering than they ever are from under-watering.
A saying that comes to my mind If I am uncertain whether I should or shouldn’t water any of my cacti and succulent is, ‘If in doubt do nowt as these plants can adapt to drought’.
I think of cacti and succulent plants as the Camels of the plant world. haha! as they are quite capable of going for very long periods without any water, sometimes months and even years in their natural habitats of the harsh, dry arid desert regions that most of them are from.
With all the desert cacti and succulents, I water them from Spring until early Autumn. In Ireland for me watering begins from early March until early October, I discuss later about watering through Winter.
In Spring and Summer I water them only when the pots have completely dried out before watering them again.
Rather than pouring the water directly in around the base of the plant I usually always pour the water over the top of the plants letting the water cascade down the body of the plants using overhead watering as much as possible, as this helps to keep them clean and dust free and helps prevents Red Spider mite attack.
However I avoid overhead watering with any of the ‘hairy’ ones like the Espostoa cacti, Cleistocactus strausii etc, and succulents such as Echeverias as water can sometimes collect in the hairs and rosettes and may encourage rot, so water these at the base of the plant..
Plants that are overhanging the edges of their pots I water from below the actual pot and place the water in the saucer/tray that they are sitting on, sometimes 3 or 4 watering’s are given in the saucer over a series of hours until the plant has fully soaked up the water.
I never allow water to sit in the saucer permanently as this will encourage root rot, and if there is any water still sitting in the saucers after a few hours this gets emptied away.
With all of the Epiphytic (Rainforest) cacti such as Schlumbergera, Rhipsalis, Epiphyllum etc I will keep these well watered at all times during the Spring and Summer, and I do not let them dry out completely before watering them again, like I do with the desert types of cacti as mentioned earlier.
The Epiphytic cacti come from a natural habitat of tropical and humid rainforests and grow naturally hanging from trees for support, alongside other moisture loving plants like Orchids and Ferns and they do not appreciate being kept dry for too long.
For all of my plants I avoid watering during the daytime on very hot and sunny days, as the water droplets on the plants can act as a magnifying lens behind glass and can leave scorch marks on the stems, so It is better to water either first thing in the morning or last thing of an evening.
When it comes to the type of water that I use, I always recommend using clean rainwater as much as possible to water your plants, as tap water is often high in chemicals as well as having a high pH.
Most tap water is hard alkaline water with a high pH that over time can make the pH of your soil too high, and this may encourage root loss and or rot. The ideal soil pH should be between 5.5 to 6.5 pH.
The range of water pH you will be looking for is also in this range, so check with your local water company to find out the pH of your local tap water, but you can purchase a pH tester kit from a local garden centre or aquatic store and test this yourself.
I don’t use a soil pH tester, but I do use a paper pH tester to test on my rainwater as these testers are so cheap to purchase and all you need to do is simply dip the tip in the water you are testing and align it with the numbered coloured scale.
When I lived in England the tap water in the region I was living was not hard water, but when I came over to Ireland 9 yrs ago, for the first year I used the tap water not thinking about the pH and I lost some plants due to root loss which surprised me as I was always very careful with watering..
I realized that it could be the water and I tested the tap water and the pH was 9, WOW my eyes came out on stalks 🙂 🙂 and my screams were heard for miles 🙂 haha
Luckily I switched to rainwater, and since switching to using rainwater my plants have thrived, and thankfully being in Ireland I have an abundance of rain water always on hand haha!
On the rare occasions my rainwater ran out, I successfully have used tap water with white vinegar to bring down the pH of the tap water, but this can be time consuming if you have a very large collection, but definitely worth it if you are unable to get access to rainwater.
Depending on the amount of water you need to use, you will need to gradually add the white vinegar and test it with your pH tester to get the desired pH level.
As a rough guesstimate 🙂 add roughly 3 to 4 teaspoons of white vinegar per 5 gallons of water (25 ltrs) but really add a little at a time stir it well, test and use accordingly.
I noticed such a huge difference in how healthy the root systems of my plants are when I come to re-pot them after using rainwater, compared to years ago when I got caught out by using tap water with a high pH.
When it comes to the temperature of the water, never water your plants with icy cold water as this will shock them and their root system, so I always recommend using tepid rainwater that has naturally became tepid as a result of sitting in a container in your greenhouse or a warm location..
Check out this video I made on why I use rainwater to water my plants and watch out for the funny clip at the end where my partner Sean does an Irish jig in between a lightening storm haha!
Watering during the Winter
The Desert cacti and most of the succulents do not need to be watered during the Winter months as long as they are kept cool and dry.
However there are a few exceptions to this and these are the Autumn and Winter growing Succulents such as some of the Mesembs, e.g Lithops and Conophytums, as well as some of the Crassulas, Tylecodons, and Aloes etc. I still keep these very lightly watered every 3-4 weeks.
The Epiphytic cacti such as Rhipsalis and Schlumbergera are in their flowering periods during the Autumn and Winter, and should never be allowed to totally dry out during the Winter.
While no serious harm will come to the Epiphytic cacti if they are kept dry for short periods over the Winter, they do have a tendency for their stems to shrivel, and many of the Schlumbergera cacti will drop their buds and blooms if kept too dry.