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Cacti and succulents
- Succulents have thick fleshy leaves or stems.
- They require only modest amounts of water and fertilizer, but do need abundant light.
- Most cacti and succulents grow in well-drained sandy soil.
- They are well adapted to living in houses where the relative humidity is low.
- Pests are a rare concern for cacti and succulents.
- Stem cuttings are an easy way to propagate cacti and succulents.
Houseplant enthusiasts look for different and more exotic specimens to add to their collections. Beginners and experts can find many good choices among the cacti and succulents.
The term succulent refers to a broad, loose category of plants, including cacti, which have developed thick fleshy leaves or stems. These serve as water storage organs to insure survival under arid conditions.
Succulents are found worldwide. Besides cacti, they include many familiar plants:
- jade plant (Crassula arborescens)
- snake plant (Sansevieria trifasciata)
- medicine plant (Aloe barbadensis)
- century plant (Agave americana)
- flowering Kalanchoes (Kalanchoe blossfeldiana) and the sedums (Sedum sp.), both sold as gift plants
- hens and chicks (Sempervivum sp.), common in the perennial garden
- The cactus family has nearly 2,000 species, and with one exception all are native to the Americas.
- They range from the Arctic Circle to the mountains of Chile, but are most common in the southwestern United States and Mexico.
- Cacti can be tall and lanky or squat and spherical, frequently without any branches and almost always without leaves.
- These shapes result in a large proportion of internal tissue to external surface area. This reduces the amount of moisture that is lost through the plant itself.
- They often have scales or spines ranging from microscopically small to wickedly large and barbed.
- These protect against predators and are thought to aid the plant in withstanding the sun’s heat.
Growing cacti and succulents
Succulents require only modest amounts of water and fertilizer, but do need lots of light.
- Place succulents in a bright, sunny window.
- Artificial lighting can make up for insufficient natural light.
- A cool white fluorescent tube, or a combination of daylight and natural white fluorescent tubes will give good results.
- Position them 6-12 inches above the plants, and keep them on for 14-16 hours each day.
In nature, most cacti and succulents grow in well-drained sandy soil. Duplicate these conditions indoors.
- A mix of one part potting soil and one part coarse sand is usually porous enough.
- A good test is to moisten the mixture and squeeze it in your hand. On release, the soil should fall apart.
- Both pot and growing medium should be sterile.
- Grow these plants in pots with drainage holes because excess water trapped in the soil will result in rotting and decay in a very short time.
- During the low-light winter months, water cacti and succulents only enough to prevent shrinking and withering.
- When watering, do it thoroughly.
- Water should flow through the drain holes. Discard excess water after a few minutes.
- A series of repeated shallow sprinklings often results in distorted growth.
- As the amount of light increases in the spring, so does the plant's need for water.
- Always allow the soil to dry out completely between waterings.
Cacti and succulents have relatively low nutrient requirements.
- Cacti need fertilizer only once or twice a year during the late spring or summer when they are actively growing.
- Use a houseplant food that is higher in phosphorus than nitrogen, diluted to half the recommended rate.
- Fertilize other succulents in the same manner three or four times during the brighter months.
- You may be able to bring your cacti and succulents into bloom indoors if you can create their native winter conditions. This involves a combination of good light, dry soil and cool nights.
- A windowsill location will give the necessary light and cool night temperatures.
- Some cacti that are easy to flower indoors are species of Mammillaria, Gymnocalycium, Lobivia, and Rebutia. Do not be fooled by the presence of tiny, brightly colored straw flowers commonly stuck into the tissue of small cacti sold commercially.
- Many cacti and succulents are well adapted to living in houses where the relative humidity is low (10-30 percent).
- Many cacti and succulents benefit from spending the summer months outdoors.
- Once the weather warms up, place them in a semi-shaded, protected area of the yard. Gradually move them to a sunnier location.
- Avoid locations where they will receive hot, intense sunlight from 11 a.m. to 3 p.m.
- Once outdoors, these plants will require more water. Check them regularly.
Cacti and succulents are often grouped together in shallow dish gardens. While this may be an attractive way to display your plants, take several precautions.
- Choose plants that are compatible in growth rate so that one or two plants do not outgrow the rest.
- Even more important, the plants must have similar water requirements.
- Most cacti need less water than other succulents.
- Since shallow dishes seldom have drain holes, do not overwater the plants.
- Broken clay pot shards or coarse gravel at the bottom of the container may provide some drainage.
- Excess moisture will eventually be drawn back into the soil, which may keep the roots wet too long.
Pests are a rare concern for cacti and succulents.
- If they have mealybugs or scale, wipe them off with alcohol-dipped cotton swabs.
- Maintain good cultural conditions, such as bright light and proper watering, to prevent fungal or bacterial rots.
You can propagate cacti and succulents easily by stem cuttings. Many succulents will form new plants from leaves which have been broken off.
- Allow the cutting wound to air dry.
- Stick the cutting into slightly moistened, sterile sand.
- Water sparingly since moisture retention is not a problem.
- When the roots have formed, transplant into the regular sand and potting soil mixture.
- Since cacti and succulents are diverse, consult a textbook regarding the specific requirements of individual species. Libraries and bookstores have many well-illustrated books to aid in plant identification.
Reviewed in 2018