Cactus from Seed to Bloom

Everyone knows cacti. However, for many people, they are just "prickly balls" that bloom once every seven years and are best not touched. What a shame, because cacti are very undemanding plants to grow and their flowers attract considerable admiration. If a cactus grown from seed blooms, the grower's joy is even greater. It's the culmination of their growing efforts, something like a medal of merit. So what do you need to do to earn it? The first step is to purchase quality seeds, and then all that remains is to arm yourself with patience and enthusiastically start growing cacti.

Basics of Growing Cacti – Sowing Seeds

The foundation for successful cactus seed sowing is choosing the right sowing container and substrate. Choose the container according to the number of seeds being sown. A very simple sowing device is, for example, a mini greenhouse. It's more practical not to sow cactus seeds directly into the mini greenhouse, but rather into pots that you place in the sowing device. Firstly, you have the individual cactus species separated from each other, so you don't have to worry about dividing the tray to prevent the cacti from mixing. And secondly, if the sowing is affected by mold, you can conveniently remove and treat only the specific pot.

To minimize the possibility of mold infection, it's necessary to thoroughly wash and ideally disinfect the box and pots (for example, with a weak solution of hydrogen peroxide or potassium permanganate solution). The substrate is sterilized with heat – you can pour it onto a baking sheet and bake it in the oven for a while, or put it in a jar that you boil in a water bath (as if you were canning). It's a bit labor-intensive, but it's really worth it to reduce the risk of mold infection. The substrate for sowing should be fine-grained so that the seeds don't get too deep. You can create it, for example, by mixing gravel, river sand and soil, or by mixing cactus substrate and gravel. Fill the pots with the prepared substrate to the surface and press down gently, moisten the surface with boiled water. Spread the cactus seeds evenly on the substrate. Place a label with the cactus name in each pot. Then close the sowing so that contact with the external environment is minimal. Place the sowing device on a windowsill where there is enough light. However, be careful that the solar radiation isn't too strong and doesn't burn or cook the germinated plants – it's better to shade them. The second alternative is placing the cactus sowing under artificial light – a fluorescent lamp. This option can be done economically, for example, by placing the sowing in the gap between the top glass of an aquarium and the light source (if it's spatially possible).

Sprouted cactus seedlings have sufficient light and higher temperature, which contributes to successful growth. Observe the cacti regularly and in case the substrate dries out, water them with boiled water. If, despite all efforts to sterilize the environment, you notice white mold threads spreading in the pot, immediately remove it from the seed propagator, spray it with a weak solution of potassium permanganate, and let the substrate dry out. Remove any dead seedlings. After the cactus seeds germinate, start ventilating the sowing, but keep it constantly slightly moist.

When the seedlings start to crowd in the dish, prick them out into a larger pot (dish). Be careful during this work, because the young cactus body is very fragile and susceptible to damage. The larger the cactus you're working with, the lower the risk of damage. Transplant into dry substrate and never water cacti after transplanting - give them about a week for small wounds caused by transplanting to heal. Watering can cause rotting, even in adult plants!

Basics of Cactus Cultivation – The Grower's Year

When growing cacti, it's essential to follow the summer growing season regime and the winter dormancy period. It doesn't matter whether you grow cacti in a greenhouse or at home on a windowsill. Without following this principle, you'll hardly see any flowers. The summer growing season begins approximately at the end of April, at an outdoor location when there's no risk of frost. Place the cacti on a windowsill or in a greenhouse and start watering them – approximately once every 14 days, considering the current climate conditions – in warm weather and fast drying you can water more frequently, in cold weather less often. The substrate should dry out between waterings. A cactus "awakened" in this way will "drink" and start growing; in flowering-capable cacti, buds will appear. Keep the cacti in this growth regime until September, then gradually reduce watering. The cacti's tissues will mature and prepare for the dormancy period. At the end of October (bring them in from outside before frost arrives), move the cacti to a cooler location, optimally with a temperature around 7–15°C. It can even be completely dark there (cellar, shoebox), provided the temperature is lower.

Try growing a Christmas cactus too – it's not difficult at all. It can create a pleasant atmosphere.

Don't water cacti during the winter period! Except, of course, for small seedlings, which should be occasionally watered and kept in light. Check the cacti occasionally. If you notice that the top is light green and starting to stretch, the temperature is too high and the cactus has started growing – either lower the temperature or switch to the summer regime – but not before the end of March. Following these two regimes is the key to success in cactus cultivation, especially for flowering.

Most Popular Cactus Species

• Ariocarpus – cacti of this genus are among the more challenging to grow, but all the more valued. They occur from northern Mexico to southwestern Texas. Flowers are white, yellow, pink or purple, growing from the crown of the cactus. A distinctive feature of this genus is the strong taproot. Representatives of this genus include, for example, ariocarpus fissuratus, which grows up to 15 cm in size and produces pink-purple flowers up to 5 cm wide in autumn when mature. In its homeland, Americans call it "living rock" due to its unusual appearance.

• Astrophytum – the distinctive feature of this Mexican cactus genus is white flecks scattered all over the cactus body. Flowers grow from the top of the plant, usually yellow with red or orange throat. The best-known species is astrophytum asterias, which got its name due to its resemblance to a starfish. The species name astrophytum capricorne is derived from Capricorn, which is why it is sometimes called "goat's horn cactus". Astrophytum myriostigma has no spines and, as the name suggests, is covered with thousands of white dots (flecks). It is also known as "bishop's cap", which it resembles in shape. There is also a "nudum" variety without flecks. Astrophytum supercabuto belongs to Japanese hybrids and is valued especially for its appearance - the flecks are larger than in common species and form an interesting pattern on the body. Other representatives of this cactus genus include astrophytum niveum, astrophytum senile, and astrophytum crassispinoides.

• Epithelantha – these cacti belong to Mexican miniatures, growing to a maximum size of 5 cm. The spines are white and very short. Flowers grow from the crown of the plant. They are very small, white or light pink. Striking on these plants are the dark pink seed pods that form after flower pollination. A representative of the genus is epithelantha micromeris. The species name of this cactus means few-numbered or composed of few parts. In their homeland, epithelanthas are called "mulato" by some tribes and are used as hallucinogenic narcotics. In the Czech Republic, the concentration of juices is not sufficient (due to lack of sunlight), so it has no hallucinogenic effects!

• Thelocactus – this cactus species originates from northeastern Mexico and southern parts of Texas. It grows in warm subtropical deserts with gravelly to sandy soil, so even when cultivating in our conditions, it requires very permeable substrate (doesn't tolerate waterlogging) and a warm location. Large flowers grow from the apex and can have various colors. Representatives include Thelocactus bicolor, which has striking two-colored spines and a bright pink flower. Furthermore, Thelocactus hexaedrophorus, which has distinctly gray-blue epidermis (skin) that distinguishes it from other representatives of this species. It blooms with a creamy white flower up to 5 cm large. Thelocactus rinconensis is a beautiful representative of this species, easy to cultivate, the only disadvantage is that it blooms only around 10 years of age.

• Echinocereus – cacti of this species are columnar, widespread from Mexico to Texas, California, Colorado, Utah, and Nevada. Flowers grow from the side of the plant and, unlike other cactus species, can bloom for up to a week. Representatives include Echinocereus chloranthus var. cylindricus with smaller brown-yellow flowers, Echinocereus rigidissimus with large pink flowers, and Echinocereus viridiflorus with yellow flowers. This cactus is temporarily winter-hardy down to temperatures of -20 °C.

Tip for Conclusion

Purchased cactus seeds can also be sown using the so-called Fleischer method – i.e., in sealable preserving jars (with glass lids). The advantage of this method is airtight sealing, which achieves higher sterility of the environment and constant moisture. The disadvantage is that sowing is done directly into the jar, so if affected by mold, you cannot remove just one pot. We recommend growing using a Growset, which is also suitable as a gift.

See also Cacti - Prickly Beauty That Doesn't Fade