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How to Care for Mexican Fence Post Cactus?

Are you looking for a plant that gives typical deserty vibes? If so, Mexican Fence Post cactus is definitely for you.

Let’s face it, we all adore plants and want that jungle effect at our your. However, we often kill several of our plants that constantly troubles us.

But, it definitely will not be the case with the Mexican Fence Post cactus. The plant is easy to care for and can easily thrive under certain neglect.

Mexican Fence Post cactus is a sun-loving plant that enjoys a plethora of direct sunlight, the humidity of about 40%, fast-draining soil, and a warm to a hot temperature ranging from 70°F to 80°F (21°C to 27°C).

Mexican Fencepost Cacti in a Pot
Mexican Fence Post cactus (Source: Etsy)

If you are looking to bring the variety home, here is a care guide that you need to follow.

Mexican Fence Post Cactus Overview

Mexican Fence Post is not your ordinary cactus that is small in appearance. It is a giant variety of cactus that can reach a height of about a stored building.

The cactus grows columnar with its dark green-gray thick ribs and white spikes.

It is generally planted in backyards or at the front of the house as it acts as a fence. The spiky thrones and the high body of the cactus can easily defend animals and thieves.

If you want to know more about the Mexican Fence Post cactus, here is a complete overview of the plant.

Scientific Name Pachycereus marginatus
Latin NameLophocereus marginatus
Common Name Mexican Fence Post Cactus,
Organ Pipe and
Organ Cactus
Family Cactaceae
Origin Central Mexico
Plant TypeCactus & Succulents
Growth Zone Minimum cold hardiness Zone 9b
-3.9 °C (25 °F) to -1.1 °C (30 °F)
Height Up to 20 feet (6.1 m) in height
Spread About 6 feet
Flowering HabitsBears small pinkish-red inconspicuous bloom
In spring and late summer
Toxicity/ Edibility Produces edible, dark-red, sweet fruits that are edible
Non toxic to human and pets
Pollinators Wind or birds or bees

Where to Buy Mexican Fence Post Cactus?

You can get this giant variety of cacti in online portals and nurseries. The species might be a bit high on a budgetary basis, but it is worth the investment.

Here are a few portals where you can buy Mexican Fence Post cactus.

Places to Buy Expected Delivery
AmazonYou will most likely get your product within 7 days
ebayIt will deliver your product anytime between 30 days.
EtsyYour product will likely arrive between 7-10 days
The succulent source You will receive your product within 7 working days

Mexican Fence Post Cactus Grow and Care

The plant grows in the Mexican and southern part of the U.S.A., where high temperatures and low moisture characterize the climate.

The plant is naturally adapted to grow in desert areas and harsh conditions; it is extremely easy to care for. Therefore, I say it is difficult to kill the plant than to care for it.

That being said, you cannot just leave the plant on its own. You need to provide it with the bare minimum care to thrive. Besides, growing it indoors is quite thornier.

Here is a quick table about the growing conditions of the Mexican Fence Post cactus.

Parameters Favorable condition
Sunlight 8-10 hours of bright direct light
Watering Once in 2-3 weeks during summer
Reduce the frequency to half during winter
Temperature 70°F to 80°F (21°C to 27°C)
Humidity Around 40-50% of the relative humidity
Soil Type Light, porous, and nutrient rich soil
Fast-draining soil that dries out completely in between watering
Fertilization 2-3 times a year
Pruning Rare pruning,
Only to manage size or if infested with diseases and pests
Repotting 2-3 times a year
Propagation Via Stem Cuttings and Seeds

1. Sunlight and Location

The Mexican Fence Post cactus grows in direct sunlight in its natural environment. Thus, you need to mimic the same environment to grow them successfully.

Mexican Fence Post cactus enjoys 8-10 hours of bright direct light. Although it can survive with about 5-6 hours of bright direct light, I suggest providing them with more direct sunlight.

Cactus in full sunlight (Source: Pixabay)

Signs of Insufficient Light

  • Stunted growth
  • Plant unusually tilting towards the light source
  • Reduced Photosynthesis rate disrupting all physiological function
  • Extremely Slender stems
  • Discoloration, pale or unhealthy appearance

Tips to Provide Sufficient Light with Proper Location

  • The best spot for Mexican Fence Post cactus is a southern or western-facing window reflecting the afternoon sun.
  • You can place them in an eastern-facing window. I barely recommend it as mere morning reflection is not sufficient.
  • Place the plant in an open space where no object blocks the sun’s rays in an outdoor environment.
  • Avoid shifting the plant from a brighter location to a low-light location.
  • Always rotate your cactus once in 1-2 weeks to avoid one-way growth.
  • Use a light meter to measure if your plant is receiving enough light.
  • Consider providing between 4,000-5,000 foot-candles of light intensity to your cactus.
  • In case of the aforementioned symptoms, introduce the plant to the full sun until it revives.

Can I Use a Grow Light for the Mexican Fence Post Cactus?

Mexican Fence Post cactus demands a high intensity of light. But, if you are growing it indoors, you might not meet its lighting requirement.

For such, you can use artificial grow lights. Most importantly, ensure that the light source provides both red and blue spectrum.

Full Spectrum for Indoor Plants
Full Spectrum for Indoor Plants (Source: Amazon)

A blue spectrum is associated with vegetative growths, while red is with flowers and fruits. It is ideal for providing them with 14-16 hours of full-spectrum grow lights.

Keep your cactus about 6-12 inches below the artificial light.

Furthermore, you can introduce the plant to grow light during winter as the light intensity is low.

2. Minimum watering

One of the main problems with cactus is overwatering. Always remember cactus equal minimum watering.

These plants grow in deserts where they are adapted to grow with almost no water. Besides, they store water in their foliage and trunks. Thus, always ensure that your cactus soil is dry.

Water them once in 2-3 weeks during summer and reduce the frequency to half during winter. You can water them once a month, even less in winter.

Watering a cactus
Watering a cactus. (Source: Pixabay)

Signs of Improper Watering

  • Severe drought causes discoloration pale, and browning of stems.
  • Prolonged drought causes shivering of the plant.
  • Stunted growth
  • Root rot and fungal infection due to overwatering issues.
  • Dropping and withering of trunk
  • Brown or yellow patches on the trunk

Tips to Proper Watering

  • Water the plant only when the soil is completely dry.
  • Avoid watering the plant at night as it fluctuates soil temperature.
  • Use salt-free water as excessive salt accumulation in soil injures roots.
  • Avoid excessive cold or hot water; Water your cactus with tepid water.
  • Water the plant thoroughly. Afterward, immediately empty the saucer to avoid roots sitting in water.
  • Always use well-draining potting mix and pots with good drainage holes.
  • For outdoor cacti, rainwater is sufficient. However, consider planting them in a pot if you live in a tropical climate that rains excessively.

How to Revive Overwatered Mexican Fence Post Cactus?

The plant stores water in its trunk; thus, it requires bare minimum watering. Overwatering in them leads to fungal and bacterial growth causing root rot.

Inspect the plant’s root. If you feel it mushy and soft,  there is the possibility of root rot. You need to cut off all of the damaged parts.

Then, dip the plant in a fungicide and let the roots dry before repotting it in a new potting mix. Avoid watering for a couple of weeks until the soil becomes excessively dry. Afterward, water the cactus lightly.

Unfortunately, if your cactus has gone through severe root rot, you might not be able to save it.

In case of underwatering, water the plant immediately with tepid water. The plant might fade due to unexpected water saturation. However, it will revive within 24-48 hours.

3. High Temperature

Mexican Fence Post is quite a hardy plant that thrives in low and high temperatures. But, it is best to provide them with high temperature as it is adapted to grow in a hot climate.

The ideal temperature for Mexican Fence Post cactus is between 70°F to 80°F (21°C to 27°C) or even higher.

Light Temperature Scale
Light Temperature Scale (Source: Wikimedia)

Interestingly, it can survive in temperatures as low as 50°F (10°C). However, ensure that the temperature does not drop below that range.

Extremely low temperature (below 25°F) is harmful to the plant. This might saturate water in the cell, which might even lead to its rupture.

If the plant is exposed to low temperatures for a long time, it might even die. So, better not mess with the temperature range.

Similarly, a temperature above 100°F is not very favorable for your cactus. It might show signs of browning and yellowing, along with damage in spikes.

Tips to Maintain Ideal Temperature

  • Avoid drafty areas, heating and cooling vents like air conditioners, heaters, radiators, etc.
  • You can provide insulation to prevent soil temperature loss. Mulch such as fried grass acts as a good insulator.
  • Using a frost blanket and burlap material is another way to protect plants from cold.
  • Avoid keeping the cacti outdoors during frosty nights.

4. Low Humidity

Humid environment and moisture are the culprits of Mexican Fence Post cactus. The climate of the desert is dry; thus, you need to avoid a humid environment for them.

The ideal humidity is around 40-50% of the relative humidity. You stand on the safe side of its humidity requirement as the average indoor humidity is around 40%.

An environment with humidity higher than 60% is too damp for your cactus. High humidity causes shriveling of plants and invites bacterial and fungal growth.

Tips to Maintain Low Humidity

  • Avoid areas like bathrooms and kitchen for your cactus as they are humid.
  • Use a hygrometer to inspect humidity and keep the plant in a low humid zone.
  • Avoid grouping of plants.
  • Using a dehumidifier might solve problems of high humidity.
  • Cactus does not require misting. Mist it only when the humidity drops below 30%.

5. Sandy Soil Mix

Mexican Fence Post cactus requires light, porous, nutrient, and fast-draining soil that dries out completely in between watering.

The soil must resemble the sandy texture and low moisture-holding capacity like a typical desert soil.

Soggy soil invites bacterial and fungal rot in plants. Besides, in soggy soil, air pockets are substituted by water resulting in an anaerobic environment due to lack of oxygen.

Similarly, as its roots are susceptible and tiny, avoid using highly compacted soil. Such soil exerts excessive pressure that injures roots.

Check the moisture level in the soil for confirmation. An investment in a soil meter or a hygrometer wouldn’t be something you will regret later.

Soil Meter with the reading scale information
Soil Meter (Source: Amazon)

The idea of soil mix is cacti and succulents mix. Here are a few commercial soil mixes that you can use for Mexican Fence Post.

Alternatively, you can make your potting mix. I prefer making potting mix as we can mix and match items to attain the perfect mixture.

Here is a recipe I use for my Mexican Fence Post cactus soil.

  • 1 part of cacti and succulent mix
  • 1 part of perlite or pumice
  • 1/2 part of coarse sand
  • 1/3 part of organic compost (manure, chicken litter, vermicompost, etc.)

In addition, the variety does well in soil ranging from slightly acidic to alkaline. It is best to maintain the soil pH between 6.1- 7.8.

6. Minimal Fertilization

The plant is native to a desertic environment; it does not require excessive fertilization.

Interestingly, the plant can survive with almost no feeding. However, I recommend light fertilization for proper growth.

Consider fertilizing them occasionally during spring and summer. Feeding them 2-3 times a year with a light organic fertilizer is sufficient.

Miracle Gro Fertilizer for Succulents
Miracle-Gro Fertilizer for Succulents (Source: Amazon)

However, if you are looking for synthetic fertilizer, use N.P.K. in the ratio 5-5-5. Here are some commercial fertilizers you can use for your Mexican Fence ost cactus.

Additionally, overfertilization in them leads to root injuries and stunted growth. Thus, avoid fertilizing them during winter.

7. Growth Habits

Although Mexican Fence Post is a tall cactus, it is not a fast grower.

Fence cactus can reach a height of about 20 feet in its natural habitat, whereas, in enclosed space, it grows up to 2 feet tall.

Scaling the growth of Mexican Fence Cactus
Mexican Fence Post cactus growth (Source: Etsy)

The cactus has a columnar trunk with the main stem that reaches about 3-4 inches in diameter. Similarly, its ribs are about 5-7 inches, and its central spine has a slightly yellowish color that reaches about 3-8 inches in diameter.

Along with the rib’s edges are the fuzzy spikes that give the cactus a stunning look.

Mexican Fence Post cactus produces tall columnar trunks that appear similar to a pipe organ. Since it possesses spikes and is tall, it creates fences.

Moreover, its spines are not among the large and dangerous, unlike other varieties of cactus. However, you need to be cautious that they do not poke you.

Flowering and Fruiting Habits

It produces pinkish-red tubular to bell-shaped flowers during spring and late summer. These flowers pop out of its ribs’ edges horizontally.

Once the flowers bloom, you can see them develop into fruits. It produces yellowish-red spiny fruits incapsulating black seeds within.

Besides, these fruits are edible, and birds often feast upon them. However, I do not recommend feasting upon them, although the fruits are non-toxic.

8. Potting and Repotting

Growing wild cactus-like Mexican Fence Post in an enclosed space is a trickier task. Next, if you do not use the correct pot type and size, you might risk killing them.

The best pot material for cactus is terracotta or clay pots.

Ceramic Terracotta Pots for Ming Thing Cactus
Ceramic Terracotta Pots for Cactus (Source: Amazon)

These pots possess the following benefits:

  • Sufficient drainage holes
  • Oozes out water from the surface
  • Evaporates water making the soil dry
  • Provides good soil aeration
  • Controls temperature fluctuation.

Alternatively, you can also use plastic pots and cement pots. These materials are comparatively durable but do not possess as many benefits as clay or terracotta ones.

Most importantly, I strictly warn you not you use metal or glass pots for cacti. These pots have poor drainage and aeration system, which leads to root rot issues.

Besides, metal pot constantly fluctuates temperature along with the external environment. Thus, you might stress your cacti growing in them.

Problems due to Wrong Pot Size and Type

  • Poor drainage system makes soil soggy, which causes root rot.
  • Large pots take long lime to dry water. The persistence of prolonged moisture invites bacterial and fungal growth in the soil.
  • A small size pot does not provide enough space for root development. As a result, your plant exhibit root-bound and stunted growth issues.

Tips for Selecting Correct Pot

  • It is ideal for maintaining a gap of about 14 inches between the Pot’s rim and the main cactus trunk.
  • Use a pot that is slightly larger or similar to the size of the cactus. Generally, a 5 inches pot size is ideal for the Mexican Fence Post cactus.
  • Cactus contains shallow and susceptible roots. Thus, use a shallow pot as deep pots stores water at the bottom, leading roots to sit in the damp substrate.

Repotting Mexican Fence Post Cactus

Has your cactus outgrown the size of your container? Then, it is time to repot your Mexican Fence Post cactus.

The ideal frequency to repot Mexican Fence Post cactus is 2-3 times a year.

Repotting Bunny Ear Cactus
Repotting Cactus (Source: Unsplash)

When its roots are bound, it exhibits symptoms like stunted growth, yellowing and browning of trunk or rib’s edges, and drooping.

Thus, if you can see roots coming out of your drainage holes, buckle up to repot your cactus.

Tips to Repot Mexican Fence Post Cactus

  • Put on protective gloves to protect your hands from their spiky thrones.
  • I advise you to water your cactus a day earlier to repotting. It strengthens the roots system, thus exerting less stress by repotting.
  • Now, take a fork and loosen the top layer of the soil. Remove the top 25% of the soil and gently take the plant out of the Pot.
  • Fetch a clean pot that is 10% larger than the size of your plant. Layer the base with a few pebbles to block potting mix from draining out while watering.
  • Then, half fill the Pot with the potting mix and water it. Place the cactus at the center of the Pot and fill the remaining portion with the potting mix.
  • Gently, press the potting mix and fill it till the brim. However, ensure to leave some space for future fertilization.
  • Now, water the plant thoroughly and level it in the same environment as earlier.

Note- The cactus might shrivel or turn to slighty yellow and brown color immediately after repotting. It is the stress yield by repotting. No need not worry as your cactus will revive naturally.

Also watch,

9. Rare Pruning

Generally, pruning does not fall under the cactus maintenance requirement.

Hence, you need not prune your Mexican Fence Post cactus. However, you might need to prune if it is affected by diseases.

Alternatively, you can consider pruning them to maintain desired shape and size.

Pruning equipments
Arrangements for Pruning (Source: Unsplash)

Tips to Prune a Bunny Ear Cactus

  • Put on thick protective gloves to protect your hand from prickling.
  • Always use disinfected pruning instruments.
  • Immediately prune your cactus if you see signs of infection or rot.
  • You may choose to prune its roots while repotting if they are excessively long.

10. Toxicity of Mexican Fence Post

Mexican Fence Post cactus are non-toxic to humans and pets. Just like Bunny Ear, Pincushion Cactus, and Bluetorch cactus. Instead, birds have been found feasting on their fruits without any problem.

Despite it, you need to keep the cactus away from your children and pets. It is not safe, and the tiny spikes might injure your children.

The spikes are dangerous to eyes and skin penetration.

Thus, I advise you to keep it away from the reach of children and pets.

Propagation Methods for Mexican Fence Post Cactus

Propagating Mexican Fence Post cactus is simple and easy. You can propagate them either by asexual methods or by sexual methods.

The asexual method involves propagation via vegetative parts. You can obtain identical colones or offsets by this method.

Next is the sexual method of propagation which involves pollination and propagation via seeds.

The best time to propagate your Mexican Fence Post Cactus is spring and summer.

Here are the two methods you can use to propagate Mexican Fence Post Cactus.

  1. Propagation via Offsets cuttings
  2. Propagation via Seeds

Additional Insights- Sexual method of propagation is generally used by pro-growers. Besides, the sexual method is involved form the hybridization of plants as all of the seeds are not identical.

1. Propagation via Offset Cuttings

It is the easiest method of propagating the cactus. You can use the same method to propagate almost every type of cactus.

Rooting after Stem Cuttings
Rooting of Mexican Fence Post

Here are the steps to propagate Mexican Fence Post via Offset cuttings or Stem cuttings.

Step 1

Put on safety measures like gloves, goggles, masks to protect yourself from its spiky thrones.

Next, take a sharp pruning shear and sterilize it with rubbing alcohol.


A mature Mexican Fence Post cactus branches from the main trunk. Inspect for such offset in the stem.

Make a clear incision at the base of such offsets. Leave the offset for about a couple of days for callous formation.

Step 3

Inspect if the callus has healed and dried out completely.

If so, you can dust some of the antifungal powder or rooting hormones at this point. Afterward, the stem cutting is ready to be propagated.

Step 4

Take a clean pot and layer it with a few pebbles.

Half fill the Pot with cacti and succulent mix, then place the cuttings at the center. Now, fill the remaining portion with the potting soil.

Dust off the soil with a brush if it has fallen upon the cactus. Now, water the cactus lightly and leave it in bright direct sunlight.

Avoid watering for a couple of weeks. Afterward, water it thoroughly and leave it until the soil dries completely.

Generally, the cutting will start to root within 2- 6 weeks.

2. Propagation via Seeds

It is slightly thicker compared to propagation via the stem. First, you need to harvest seeds from completely ripe fruits. Otherwise, you can also buy Mexican Fence Post Cactus seeds from local nurseries.

Once you have got its seeds, wait for a good season. The best time to germinate seeds is during spring.

Propagation through Seeds in the tray
Propagation through Seeds in the tray (Source: Unsplash)

Here are the steps to follow to propagate Mexican Fence Post Cactus via seeds.

Step 1

Take a transparent plastic jar with a lead. Poke a few holes at the bottom of the Pot and the lid.

Now, fill the jar with cacti and succulent mix—mist water to maintain slight moisture in the soil.

Step 2

Afterward, spray seeds on the potting mix. Maintain a gap of about 1 inch between seeds.

You can spray just a few potting mixes if you like, but optional.

Then, close the lid and place the pit in bright indirect light.

Step 3

You can open its lid for a couple of minutes to let air circulate and inspect soil moisture. If you feel the substrate is dry, mist water on it.

Most importantly, seeds require a warm temperature to germinate. It requires a bare minimum temperature of about 20 to 22°C (68 to 72°F). 

Thus, I advise you not to frequently open its lead and let seeds enjoy a warm temperature inside the Pot.

Step 4

Your Mexican Fence Post cactus will most likely germinate within 4-6 weeks. You can transfer these tiny cacti into a new and separate potting mix after about 8-10 weeks.

Common Problems in Mexican Fence Post Cactus

1. Common Pests

Mexican Fence Post is not highly susceptible to pests. However, it can get some common pests if neglected for a long period.

Here is a table about the common pests and their symptoms in Mexican Fence Post Cactus.

Common Pests Signs and Symptoms
Aphids 1. They are a tiny greenish-white insects.
2. Suck on plant thus causing stunted growth and discoloration.
3. Severe infestation might lead to dead shoots
Mealy Bugs1. White cotton like round sap sucking bugs appear on the trunk.
Red Spider Mites1. Fine pale mottling appears on cactus body.
2. Tiny red insects with white casts and egg shells.
3. Stunted Growth
Soft Scales 1. Sap-sucking pests which causes stunted growth
2. Brown or black bumpy structure develops on leaves

How to Treat Pests Infestation in Mexican Fence Post Cactus?

  • Deadhead infected parts using sterilized pruning shears.
  • Spray soap water or insecticidal soap to the affected parts.
  • You can pluck pests and eggs of scales using a tweezer or scrape them off using a blunt knife.
  • Dip a brush in 75% diluted isopropyl alcohol and apply it around the affected part.
  • You can spray neem oil or other horticultural oil to the entire plant.
  • In case of severe infestation, you can spray synthetic insecticides and pesticides.

Preventive Measures

  • Inspect the plant before buying it.
  • Avoid overhead watering and overwatering.
  • A blast of water might sometimes help in knocking off pests.
  • Spray soap water once a month to the entire plant. However, spray them only in the morning.
  • Avoid growing your plant with other infected plants.

2. Diseases Infestation

Mexican Fence Post is a hardy and resilient plant that generally does not attack diseases.

However, overwatering and high humid environments might cause fungal and bacterial diseases in Fence Post.

These diseases have the potential to cause root and stem rots.

Disease infested cactus. (Source: Wikipedia Commons)

The most common fungal disease in them is Anthracnose caused by Colletotrichum spp. It causes brown and black spots on the stem and mushy roots and stems.

Similarly, they are prone to bacterial rot caused by Erwinia amylovora. It causes oozing out of brown or black sap for the affected part.

How to Treat Disease in Mexican Fence Post Cactus?

  • Inspect its roots. If you feel it mushy and limp, cut off all infected parts using sterilized pruning shears.
  • Apply fungicides to its roots and leave them in the air for 3-4 days before repotting them in a new potting mix.
  • Avoid watering the plant for weeks until the soil dries out completely.
  • Apply fungicide containing copper, Benomyl, etc., in case of severe infestation.

Preventive Measures

  • Use pots with 2-4 drainage holes.
  • Avoid moisture-retaining potting mix and opt for fast-draining soil.
  • Loosen the top layer of the soil to let air circulation in roots.
  • Avoid the high humid areas for cacti.
  • Strictly avoid overwatering and overhead watering.

3. Phototoxicity Issues

Phototoxicity is a condition where the plant becomes sensitive to harsh sunlight. Although the Mexican Fence Post cactus adores full sunlight, it might not cope with extremely high light intensity.

It exhibits signs like brown or black patches on the stem, yellowing, and pale appearances in such a case.

It is a plausible problem if you live near the equator as the light intensity is severely high. As such, I recommend providing your cactus with only partial sunshine (about 4-8 hours of direct sunlight)

F.A.Qs about Mexican Fence Post Cactus

Is Mexican Fence Post Cactus Prickly?

Like other varieties of cactus, the Mexican Fence Post cactus has sharp spikes. You need to put on gloves while repotting, fertilizing, or pruning them.

If you have children and pets at your home, it is not the safest plant for sure.

Is Mexican Fence Post Cactus Easy to Care for?

Mexican Fence Post cactus do not have special care requirements. It is a forgiving plant and is suitable for newbies.

However, you need to be careful about the humidity around your plant and not overwater them.


Mexican Fence Post cactus adorns your space with its long tubular body crafted with beautiful white fuzzy spikes.

Besides, it is extremely easy to care for and multiply. What are you waiting for if you have not got yourself a Mexican Fence Post?

Bring home the beautiful cacti variety and enjoy the deserty vibe in your space.

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