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Mexican Fence Post Cactus: Best Grow & Care Guide

Do you fancy the landscape with a tall and elegant cactus or the cactus serving the garden’s bars?

You can easily fulfill your wish with Mexican Fence Post Cactus and easy care.

Generally, the Mexican Fence Post Cactus needs 8-10 hours of bright direct light, a temperature of 70-80°F, and a humidity of about 40%. Also, it prefers fast-draining soil with fertilizer and repotting every 2-3 times a year.

If you want to bring variety home, here is a care guide you must follow!

Overview of Mexican Fence Post Cactus

The cactus grows columnar with its dark green-gray thick ribs and white spikes, which can reach a height of about a stored building.

The spiky thrones and the high body of the cactus can easily defend animals and thieves.  

Scientific Name Pachycereus 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
Temperature 25-30 °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

Mexican Fence Post Cactus for Sale

You can get this giant variety of cacti in online portals and nurseries. The species might be a bit high budgetary, 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: Complete Grow and Care Guide

This cactus can thrive indoors and outdoors if it receives a great environment, i.e., warm temperature and sunny spot.

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 & Temperature

Mexican Fence Post is quite a hardy plant that thrives in full sun and hot environments. 

To mimic the optimum requirement, offer the cactus 8-10 hours of bright direct light with a minimum surviving light for 5-6 hours under temperatures ranging from 70-80°F or higher.

If there is insufficient light, the cactus can show a reduced photosynthesis rate, extremely slender stems, discoloration, a pale or unhealthy appearance, and stunted growth.

Interestingly, it can survive in temperatures as low as 50°F (10°C but can be harmful below 25°F.

Mexican Fence Post Cactus outdoor
Mexican Fence Post cactus grows in direct sunlight in its natural environment.

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

Tips to Provide Sufficient Light & Temperature

  • The best spot for Mexican Fence Post Cactus is a southern or western-facing window reflecting the afternoon sun.
  • 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.
  • You can use artificial grow lights for 14-16 hours if you grow the plant in low-light areas. Most importantly, ensure that the light source provides both red and blue spectrums.
  • Consider providing your cactus with between 4,000-5,000 foot candles of light intensity.
  • Avoid drafty areas and 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.
  • A frost blanket and burlap material are other ways to protect plants from the cold.
  • Avoid keeping the cacti outdoors during frosty nights.

2. Watering & Humidity 

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, keeping 40-50% of the relative humidity with indoor humidity of around 40%.

You can water them once a month, even less in winter. However, severe drought causes discoloration, pale, and browning of stems, ultimately shivering of the plant to stunted growth.

On the contrary, root rot and fungal infection are due to overwatering issues, causing dropping and withering of the trunk and brown or yellow patches on the trunk. 

Remember, humidity above 60% is too damp for your cactus, which can cause plants to shrivel and invites bacterial and fungal growth. 

Tips for Proper Watering & Humidity

  • 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.
  • Always use well-draining potting mix and pots with good drainage holes.
  • Avoid grouping plants and placing them in bathrooms and kitchens for your cactus.
  • Use a hygrometer to inspect humidity and keep the plant in a low-humid zone.
  • Using a dehumidifier might solve problems of high humidity.
  • Cactus does not require misting. Mist it only when the humidity drops below 30%.
For outdoor cacti, rainwater is sufficient. However, consider planting them in a pot if you live in a tropical climate that rains excessively.

5. Soil & Fertilizer 

Mexican Fence Post Cactus requires light, porous, nutrient, and fast-draining soil with a pH of 6.1-7.8 that dries completely between watering.

Like desert soil, the soil must resemble a sandy texture and low moisture-holding capacity.

Prepare DIY Potting 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.)

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, avoid using highly compacted soil because its roots are susceptible and tiny. 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.

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

Potting MixesFertilizers
Hand Blended Succulent Soil MixMiracle-Gro Succulent Plant Food
Hoffman Organic Cactus and Succulent Soil MixSucculent Fertilizer
Sprout N Green Organic Potting Mix Miracle-Gro Indoor Plant Food Spikes
Espoma Organic Cactus MixSucculents & Cactus Plant Food

4. Potting and Repotting

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

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.

Tips for Selecting the 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 contain 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.

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

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

If you can see roots from 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.
  • 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 to 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 a slightly yellow and brown color immediately after repotting. It is the stress yielded by repotting. No need not worry, as your cactus will revive naturally.

5. Rare Pruning

You need not prune your Mexican Fence Post Cactus, but you need to prune it if it is affected by Mexican Fence Post Cactus problems through pests or diseases.

Aphids, Mealy Bugs, Red Spider Mites, and Soft Scales are culprits that hamper the cactus. 

Dip a brush in 75% diluted isopropyl alcohol and apply it around the affected part. You can spray neem oil or other horticultural oil on the entire plant.

In case of severe infestation, you can spray synthetic insecticides and pesticides.

Besides, the overwatering and highly humid environments might cause fungal and bacterial diseases.

If you feel it mushy and limp, cut off all infected parts using sterilized pruning shears.

Apply fungicide containing copper to its roots and leave them in the air for 3-4 days before repotting them in a new potting mix.

Ultimately, Mexican Fence Post Cactus may need careful pruning if the impacted parts are incurable.

Tips to Prune Mexican Fence Post 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 prune its roots while repotting if they are excessively long.

Mexican Fence Post Cactus: Growth Rate

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

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

The cactus has a columnar trunk with a 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 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 cacti. However, you need to be cautious so 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 their ribs’ edges horizontally.

Mexican Fence Post Cactus flower
Mexican Fence Post Cactus rarely flowers.

Once the flowers bloom, you can see them develop into fruits. It produces yellowish-red spiny fruits encapsulating 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.

Toxicity of Mexican Fence Post

Like Bunny Ear, Pincushion Cactus, and Bluetorch cactus, Mexican Fence Post Cactus are non-toxic to humans and pets.

Instead, birds have been found feasting on their fruits without any problem.

Despite it, you must 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.

Call Poison Control U.S. at (800) 222-1222 or the ASPCA at (888) 426-4435 for pets if you need emergency help.

Propagation Methods for Mexican Fence Post Cactus

You can propagate Mexican Fence Post Cactus either by asexual or sexual methods.

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

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

Spring and summer are The best times to propagate your Mexican Fence Post Cactus.

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.

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

Step 1

Put on safety measures like gloves, goggles, and 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 antifungal powder or rooting hormones. 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

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.

Here are the steps 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, but optional.

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

Step 3

You can open its lid for a few 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 minimum temperature of about 20-22°C (68-72°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 likely germinate within 4-6 weeks. You can transfer these tiny cacti into a new and separate potting mix after about 8-10 weeks.

However, propagation methods are similar for other cacti like Saguaro and Organ Pipe Cactus.

FAQs 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 must wear gloves while repotting, fertilizing, or pruning them.

It is not the safest plant if you have children and pets at your home.

Is Mexican Fence Post Cactus Easy to Care for?

Mexican Fence Post Cactus does 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.

From Editorial Team


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 a Mexican Fence Post?

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

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