Although these plants can survive the harshest weathers in their natural habitat, when cultivated, some extra attention needs to be given. These plants need ample sunlight (or grow lights if you’re growing them indoors) so that they can retain a flat form. Without light and good ventilation, they will etiolate and rot quickly within weeks.
If growing them outdoors under direct sunlight, it would be wise to place them under a shade cloth or a shaded greenhouse for the first few months after getting them. Astrophytums can grow well under full sun after acclimatizing and regular watering.
We do not have any experience growing indoors but from what we see from other hobbyists, grow lights are essential if you do not have a sunny window. Air circulation is also important to prevent build-up of moisture and humidity around the plant.
In tropical weather, especially during the rainy season, long periods of wetness can result in fungal infections and root rot. We use a rather gritty mix that contains mostly akadama and pumice with a pinch of peat moss. That allows us to water weekly without worry.
Astrophytums are great beginner plants that are not too costly for you to learn about your growing environment.
Where can I get Astrophytums?
In the wild, Astrophytums are critically endangered due to habitat loss and poaching. They are only found in a small area in Texas. However, in cultivation, the plants are commonly found everywhere.
The first place you should try searching for one is your closest garden store or supermarkets. In Singapore, we see it in almost every market we visit. However, most of the time, you will only find nudums without variegation. For more exotic-looking plants, Facebook groups are your best bet.
Try to find your local community plant groups. Sometimes growers will let go some of their collection to make space for new hobbies and interests. You can also get growing tips and people to help identify issues with your plant. Else, you can check out this Thailand marketplace that has hundreds of posts daily selling different kinds of cacti and succulents. Make sure the sellers can ship to your country before placing and confirming orders.
Grow them from seeds
Some of the rarer cultivars can be costly and out of reach to most hobbyists that are just starting out. It would be a good idea to try growing them from seeds. This serves as a great learning experience and a method to obtain unique plants. (Jiamin: and a really good way to test your patience 🙈)
Be prepared to wait for at least a year to see the fruits of your labour but trust me, it is a rewarding process. You can read a little more about our experience in sowing seeds.
Once your seedlings are relatively stable (approx ~1cm in diameter), you can also consider grafting astrophytum seedlings onto a strong rootstock to accelerate their growth. We graft a lot of our seedlings as a way to “preview” how they might turn out in the future. A good source of seeds are your local community groups or online marketplaces like Ebay and Etsy. A good online shop that we recommend is Koehres-Kakteen. They have a huge collection of cacti and succulent seeds at good prices. Also check out Star Astrophytum for some astro-inspiration. They sell some rare cultivars and seeds too but this comes with a rather hefty minimum order.
Why are people so into astrophytums?
The rabbit hole of astrophytums can go really deep. Due to the fact that they are easy to breed and are able to exhibit many different forms, they have caught the attention of Japanese cultivators since the early 1900. After selecting over hundreds of generations, there are so many variations of astrophytums in the market today. Here is a good introduction to astrophytum hybrids if you are interested to find out more.