Cacti Care – All About Soil, Air, Water, Potting, and More
How do you care for that irresistible little cactus and those cute little succulents that just followed you home from the garden center?
Maybe you want to repot them into that pretty ceramic planter Mom gave you for Christmas last year?
- How do you do that?
- How do you avoid getting stuck by cactus spines when potting?
These and other questions will be answered here. I am a long-time cacti and succulent lover and have had hundreds of plants follow me home–I think I’m the Pied Piper of cacti and succulents.
Proper soil and water, potting, transplanting and more–I will share with you a bit of the wisdom that succulent and cactus plants have taught me over the years and how you can keep them happy and healthy.
Cacti are Succulents
Did you know that cacti are succulent plants? All cacti are succulents. Succulents are not cacti.
Many people don’t realize this and it becomes even more confusing when online plant sellers use inaccurate keywords to attract buyers. I’ve seen, for example, an Echeveria labeled “Echeveria – Cactus – Succulent.” An Echeveria is NOT a cactus!
The expression “cacti and succulents” is used everywhere in society–but in reality they are all just succulents, although I use “cacti and succulents” because it is customary. Even the CSSA uses it–they are the Cactus and Succulent Society of America.
Know the Species Name
Enabling You to Take Better Care of Your Plants
Generally when people start out with cacti or succulents, they do not care to know the species name.
I know this because, years ago, I was one of these people–I didn’t want to be bothered with any of the boring stuff, like species names.
Over the years, as my collection grew and I acquired some rare varieties, it became important to know the names. There are many advantages of knowing the species names.
You can learn about their natural habitat and place them in an optimum environment for their health.
It will be easier seeking guidance if you know the species name.
You will know when your plant might bloom, its growth cycles, pests to look out for, and more.
Knowing the species enables you to take better care of your plants. It means the difference between their thriving and merely surviving.
For some reason, I happen to love databases and created a one (using FileMaker) that contains notes on my over 200 plants.
I have a record of the dates I planted seeds, made a cutting, or divided a plant. When I find obscure information on my rare plants, I record it in this database. There’s even a record for the dead plants because losing one is usually an important lesson.
Beginners growing more common cacti and succulents can usually get by without getting into the species names. But if you’re getting more serious, and really love your plants, you’ll definitely benefit from knowing and researching them–and even maintaining records about the species.
Love and Your Plants
Think of it this way, you have a relationship with your plants because you are the caregiver. If you were in a relationship with a human, you’d learn their name, pay attention to their characteristics, their signals, their needs. Doing this is loving. So please love ’em.
Why the Species Name is Important
When I first acquired these fuzzy rare gems called Conophytum stephanii a few years ago, I didn’t know anything about them–just that I needed to have them–they had my name!
These are rare plants and finding particular information a particular rare species is not that easy. I hadn’t yet located a copy of the best rare book on these rare plants, which told me that they prefer a shady spot, unusual for a Conophytum.
So that explained why they did not grow bigger and were pale with a brownish tinge. After growing them in the shade for a year, they’re now a happy, pretty green. Without the species name, I could have lost the plant.
What is in a Species Name?
Genus and Species. The names of plants like Mammillaria longiana, Astrophytum asterias, Haworthia pumila, and Euphorbia obesa, are stating the genus followed by the species.
The genera (plural for genus) are Mammillaria, Astrophytum, Haworthia and Euphorbia and are properly capitalized. The second part is the species name and is properly written in lower case.
For example, Mammillaria longiana (shown in the photo on the right), “Mammillaria” is the genus and “longiana” is the species. Mammillaria is a member of the Cactaceae family–it is a cactus and one of the ones listed on my desert plant list.
Don’t Do These Things! Learning is process and sometimes when you accidentally kill a plant, you learn. Every cacti and succulent expert has killed some, at least in the beginning.
So I am going to tell you what will kill them so you know what not to do, and if you ever do any of these things I hope you learn from them. I wish someone would have given me this list when I was younger and just beginning to grow succulents.
1. Water them every day and keep the soil moist–over-watering causes rot and they will die. This is the most common mistake beginners make–don’t do it.
2. Water them when the temperature is cold (50 degrees or less). Even if they are a little wrinkled, and it’s very cold, you’d best wait until it’s warmer.
What if it’s not getting warmer for months? Well, in that case I’d water only the soil, only about 1/2 to 1 teaspoon for a 2.5″ pot (adjust for larger pots). If you get any water on the leaves or stem, use a tissue to dry it. I lost a Euphorbia in winter, that got some of the overspray on its leaves when I was misting the Lithops (Yes, it’s a plant that likes water in winter). I wasn’t paying attention–don’t do it.
3. In summer, many of these plants do not absorb water during the day, but at night when it’s a bit cooler. Watering in the evening during the hotter months is a good strategy. Also, when watering in the heat of the day, it can be something like the equivalent of boiling water on their roots–don’t do it.
4. Leave them outside in freezing weather, don’t do it.
Secret Recipe for Growing Cactus Indoors
Good air circulation, just enough water, good light, the right temperature, well-draining soil and love is what’s needed.
Place them in an airy location. Pests tend to attack plants that are stressed by less than optimal conditions.
For example, in my mother’s courtyard where the air is stagnant, her beautiful old Jade plants (Crassula ovata) are pestered by scale insects over and over again.
Proper watering, covered in the next section, is quite long because of its importance and there is no simple rule.
Light – Most cacti and succulents enjoy bright light, with or without a few hours of direct sunlight each day. Notice where it was growing in the plant nursery and try to replicate those conditions.
Healthy cacti and succulent plants not only look good, but are much less likely to attract pests and have other problems.
If you want to move your plant from a shady location into sun, do it gradually over several days. Just like you, they will get sun-burned if they haven’t been in the sun lately.
If you have a cactus that doesn’t bloom, consider giving it more light. The spectacular flowers really make enduring those stickers worthwhile.
Cacti and succulents can also be grown under fluorescent lights, as I do with many of my plants.
Move plants gradually from shade to sun to prevent sunburn and so they can acclimate.
Temperature – Many cacti and succulents cannot endure freezing temperatures. In my climate in New Mexico, I bring my cactus in for the winter.
If a freeze comes on suddenly when you’re out of town, the devastating result is what you see in the cactus photo in the previous section.
As a rule, I do not allow my plants to experience temperatures below 45 degrees. While they may survive a night of freezing temperatures, if they freeze on consecutive nights, they will die. It is best to avoid freezing all around.
Acidity / Alkalinity (pH) – The acidity or alkalinity of the soil is represented by pH. Most succulents and desert cacti grow well in slightly acidic soil, 6 on the pH scale. Limestone soil, like the soil in my yard, is very alkaline. Water that is high in mineral content, e.g., “hard water” will increase the alkalinity of the soil over time, while acid rain increases acidity. Epiphyllum, a tropical cactus, grows well in acid soil with high peat content.
If you’re just starting out, you need not worry too much about pH as long as you are growing more common plants and using the soil recipe here. For good details about soil pH, check out this website.
If you fertilize your cacti and succulents, apply at 1/3 the strength of the recommended amount, or use a fertilizer specifically for cacti and succulents (usually hard to find).
Fertilizer – I fertilize my plants very rarely, only during their active growing period, and usually only if I have not repotted them in the last year or so.
When the soil is refreshed during repotting, more nutrients are available to the roots. If you must fertilize, do so sparingly and at 1/3 the strength of what is recommended for regular house plants. Consider their natural habitat where they don’t get a lot of extra nutrients. There are many growers who like to fertilize them more than I do.
The secret recipe is not really a secret. Good air circulation, just enough water, good light, the right temperature, well-draining soil and love is what is needed.
How Often to Water Cactus
What the Plants Have Taught Me. Cacti and succulents need just enough water. Proper watering of cacti and succulents is most important.
The factors that determine how much water they need are: how succulent they are, if they have a well-developed root system, size of their pot, soil composition, if a top dressing of gravel is used, and temperature and humidity.
Generally, cacti and succulents with thicker stems and leaves can be watered with less frequency than those with thin stems and leaves.
Plants in smaller pots need less water than those in larger pots.
A plant with a well-developed root system can absorb more water than one with a small root system. You may need to water the latter more frequently until the roots grow.
It is always best to err on the side of under-watering. If you think it’s time to water, wait three days and then water.
Using an extremely well-draining soil mix, like the one on this page, will dry out more quickly because it is airy.
With the addition of a top dressing, like gravel, the soil dries out more slowly.
It is always best to err on the side of under-watering. Some of the signs that the plant is thirsty are: cactus ribs becoming more defined, skin wrinkling, or leaves drooping. Some plants become pale when thirsty, like my Aloe vera plant.
I tell my friends and family, if you think it’s time to water, wait 3 days and then water. This is what brought me success for a long time until I got better at sensing when it was time to water.
Cacti and some succulents are dormant in winter, when I water them extremely lightly about once in 4-8 weeks.
A tip from Steven Hammer, reknown author and South African succulent expert, is to smell the soil when its damp. Then when you think its time to water, smell it. Damp soil and dry soil are very different. If you practice, it will become a skill. This has helped me tremendously with some of my rare succulents and cacti.
Chlorine-free water is healthier for all your plants.
Chlorine kills bacteria and microbes in water. It is not good for plants either. I use filtered water to remove the chlorine. If you are not able to filter your water, I recommend letting it sit for a few days so the chlorine can evaporate. Many people use chlorinated water to water their plants–my recommendations are for optimum plant health.
Over-watering one time, generally does not kill them, especially with well-draining soil, but do it a few more times and you may lose the plant.
As an example, during warm weather I water most of my plants once a week, sometimes twice. There is 90-110 degree heat and dry air.
Most of the cactus are watered only once per week.
The fleshy, soft succulents, like Sedum and Echeveria usually are watered twice a week.
If your climate is cooler or more humid, you will need to adjust your schedule accordingly.
How to Pot a Cactus Plant
Plants from your local nursery can live in the plastic or clay pots that they are growing in, but you might want to plant them in a pretty pot or make a dish garden.
If your plant arrived from mail order, they will likely be “bare root,” meaning without soil–they should be potted immediately upon arrival. The following step-by-step instructions will get the job done.
If you are repotting, or potting a cactus and don’t want to get stuck with those thorns, please keep reading–additional instructions follow.
- Bowl and a spoon for mixing
- Pots, your choice
- Commercial potting soil mix (see note below)
- Pumice (Perlite may be substituted)
- Diatomaceous earth (optional Sciara Fly / Root Mealy Bug preventative)
- Gravel as a top dressing
The addition of pumice to the soil mix is possibly the best tip on this page–It improved my growing success 200%.
You may use a commercial cactus and succulent mix or regular potting soil. The mixes are usually high in peat, and in my experience, do not provide adequate drainage which is the reason for adding pumice. Before I was adding pumice, my success rate was much lower–this is one of my best tips for success.
The recipe that I provide here is for beginners to get started quickly with growing some of the more common cacti and succulents. If you would like to adjust your mix, Daiv Freeman at Cactiguide has written about various soil components.
Cactus Soil Recipe
- 1 cup Soil Mix (no added fertilizer)
- 1 cup Pumice (Perlite may be substituted)
- 1 tsp. Diatomaceous Earth (optional)
- Measure the ingredients.
- Place ingredients into a bowl.
- Mix the soil components thoroughly.
Soil Ingredients – at Your Local Garden Center – or Online
Some of you may not be familiar with diatomaceous earth and perhaps the other ingredients. Here’s what I’d buy. Products and gardening tools are from Amazon.
The first three items are your soil components. Diatomaceous earth is a preventative for root mealy bugs and Sciara fly larvae and is optional. The gravel is for a top dressing, helps retain moisture and looks nice.
When To Repot
Normally, if you have a plant that is too big for its pot, it’s growing over the edges, doesn’t drain, roots are protruding from the drainage holes, then it is time for repotting. Often repotting stimulates plant growth and makes not only the plant quite happy, and it thrives.
Usually you can plan on repotting every two years or so, or when the root growth dictates. Many slow-growing rare plants may be in a pot for 5 years or more.
The photo shows an extreme case of the need for repotting. This plant is Euphorbia milli, which possesses many thorns similar to some cacti–it is the plant in the repotting demo, where I will show you how to handle any thorny plant or cactus. Knocked over several times by my cats, it lost its gravel and top soil.
Don’t get stuck when potting cacti and thorny succulents. Wrap a newspaper handle around the plant to lift it into its new pot.
One of the few plants that I consider hard to kill, it survived 3 months without water. Part of it died at one point, and I was debating throwing it away and forgot about it in the corner of my patio. The plant was determined to survive and has come back, looking pretty good. Now that it has been repotted, it will soon show increased new growth.
Cactus Growing Kits
A friend brought me back one of these on a trip to Arizona–it was Saguaro cacti seeds kit. At that time, I had never grown cacti or succulents from seed before and it was extremely exciting to see them germinate and grow into a real cactus plant on my windowsill. See photo under “How to Pot a Succulent Plant” above.
I recommend this for everyone, kids and kids at heart. If someone gave me one of these again, I’d still be excited.
Now, Go Out and Grow Some Beautiful Cacti and Succulents!
I hope you’ve found this guide helpful. Feel free to leave your cacti and succulent questions in the Comments section below. I’ll answer them to the best of my knowledge.
Don’t forget to read my other Succulent pages, especially the one on Haworthia, which are perfect plants for beginners.