The Mammillaria nejapensis (Mammillaria karwinskiana subs. nejapensis) is a cactus that is also called silver arrow cactus, owl eyes or royal cross. This cactus is native to several parts of Mexico, including places like Oaxaca, Teotitlan, Totalapan and Las Animas.
The silver arrow cactus features a singular stem that is spherical or globose in shape. It can grow up to six inches in height and is full of numerous tubercles and up to five radial spines on the tips of each tubercle. The flowers are cream and red and form a crown around the stem.
39 Mammillaria Cactus Types and Care [With Pictures]
How to Care for Mammillaria nejapensis
It is important that silver arrow cacti grow in a good medium of soil that includes a combination of sand, perlite and organic fertilizers or compost. You can either combine these materials on your own by looking up their required quantities or you can buy a mix of good quality from a store.
In essence, whether you make the medium or buy one, it is important that it should have sufficient drainage properties and enough room for the roots to breathe in. It should be moist enough (and not too moist or dry) and should have a good consistency.
Once you have your medium ready, you will need to transfer the Mammillaria nejapensis to a container for germination and further growth. This container should have enough holes in it for drainage and should be large enough for the seedlings.
The same factors apply to the pot that you will transfer the seedlings to after they reach a certain height. This pot should be big enough to allow the silver arrow cactus to grow over the next few years.
Water your Mammillaria nejapensis regularly. See if the water has dried out from the previous time you watered the silver arrow cactus. If it has, you can water it again. Make sure you do not water it excessively as this will hinder its growth. When it is winter, stop watering it completely as this is when they are dormant.
You should make sure that you do not provide excessive care to your cacti during their period of dormancy in winters. This will hinder their growth and health in other seasons. Further, they need this dormancy to bloom flowers during spring. This is why it is important to largely leave them alone in winters.
During the germination process, do not overwhelm the seedlings with moisture. Water from under the seedlings to prevent damping off.
Exposure to Light
Mammillaria nejapensis usually require intense light, so they love the outdoors. Some species, however, may not be able to thrive in such direct and strong light for longer than a few hours. Make sure you do enough research about the particular species that you are growing and how much light it requires.
If, however, you are growing these plants indoors, make sure you place them in an area that gets sufficient light. This can include a windowsill, a balcony or a plant room with grow lights. It would be a good idea to keep increasing their exposure to sunlight for their healthy growth and survival.
Do not suddenly expose them to too much light as this could make them wither. Instead, do this in increments.
Exposure to Heat
At most times, including germination and later growth, the Mammillaria nejapensis perform best when they are exposed to a temperature of 70-80 degrees Fahrenheit. Thus, you must make sure that they are exposed to this kind of heat on a regular basis.
In winter, their heat requirements are lower and can survive in slightly lower temperatures. However, if it gets too cold, it would be best to keep them indoors.
If the natural temperature is not warm enough, try to keep some source of heat nearby so that it makes it easier for them to thrive.
When it comes to fertilizing the Mammillaria nejapensis, you need to ensure that you use fertilizer on a regular basis. This is a particularly important step during the germination and growing process as it will lead to healthy growth while preventing the growth of fungi.
Usually, cacti require water-soluble fertilizers. Make sure the nitrogen content in these is not too high and that they are rich in phosphorus.
In winter, you can stop fertilizing these cacti. This is because they become dormant during winters and do not require to be fed and cared for as intensely as in other seasons. This dormancy is important for them to later bloom in spring.
Initially, after the Mammillaria nejapensis seedlings have grown enough, you will need to transplant them into separate pots where they will be able to grow healthily. For this, scoop the seedlings out carefully, fill in the new pot with enough soil medium and then plant the seedlings in the pot.
However, this is not the end of it. It would be a good idea to change the pot every three years. Shift to larger and larger pots each time to accommodate the growing size of the cactus.
You can do this at any point in the year. However, make sure that the soil is dry enough before you shift the silver arrow cactus to a new pot. Once you have managed to shift it, do not water the cactus for a few days as this could overwhelm the roots.
Preventing Pests and Fungi
It is possible for pests and fungi to grow on the Mammillaria nejapensis or medium.
When it comes to pests, they can spread quickly throughout the entire plant as well as from one plant to the other. They are difficult to spot as they may be between all the spines or even below the soil.
It is important to ensure good conditions of the cactus for this reason. You can also use rubbing alcohol for this purpose.
Fungi or bacteria can also grow easily due to inadequate growing conditions. These may include dirty pots, too much moisture due to excessive watering and incorrect ways of watering.
These fungi or bacteria may infect various parts of the Mammillaria nejapensis or cause it to die completely. In case of an infection, you will need to remove the infected parts completely. If it has died, there is nothing more that you can do to revive it.
Mammillaria nejapensis is a plant that you can grow and care for on your own. We provided a list of ways in which you can care for your cactus friends. All you need to do now is put them into practice.
If you are enthusiastic about plants or are a new plant guardian, it is highly possible that you have these cacti under your care. You might even be looking to grow or buy one but are worried about the process of keeping it alive. We hope that knowing more about its care requirements has made you more confident about this.
You simply need to ensure that your Mammillaria nejapensis is getting enough light and heat and that you are keeping it well-fed with water and fertilizers on a regular basis. Keep changing its pot every few years and that should be enough.
Mammillaria nejapensis does not require too much maintenance beyond the basics. If you stay on top of things, care for it enough throughout the year and let it rest in winter, you are good to go. So, do what it takes and help your cactus stay sharp!