Seedlings are highly vulnerable, and the high humidity needed for germination creates a perfect environment for fungal growth, which can quickly destroy your sowing efforts. To minimize this risk, sterilizing the soil is essential. A fast and effective method is to place the moist soil in a microwave-safe plastic bag and heat it in the microwave on maximum power for 15–30 minutes. This method of sterilization is suitable only for mixtures containing peat or garden soil. Pure mineral mixtures, especially sand, can become extremely hot, which may melt the plastic bag.

Once sterilized, fill your pots or trays with the moist, well-draining soil mix, ensuring the surface remains slightly below the rim. This extra space allows for a protective layer of pebbles over the seeds and prevents soil from overflowing when watering.

2. Sow the Seeds

Start by placing an identification label in the pot. If you have only small amounts of seeds, you can sow multiple species or varieties in one pot. In such cases, divide the pot into sections using plastic labels. It’s best to group species in one pot that are easy to distinguish in case the seeds shift between sections. In a 6×6 cm pot, you can divide the space into four sections and sow one regular portion of seeds (10–30 seeds) in each section.

Before sowing, use a flat tool to gently press down the substrate. This step is essential to eliminate cracks where tiny seeds could fall and become buried, as buried seeds may germinate but will likely fail to survive.

Evenly scatter the seeds over the surface of the prepared substrate, ensuring they are not overcrowded. This spacing minimizes competition and reduces the risk of fungal infections. Using a flat tool, lightly press the seeds into the soil’s surface without covering them. This helps anchor the seeds in place and prevents them from being dislodged later.

Cover the seeds with a thin layer of small pebbles (2–3 mm). They should be protected but not buried too deeply. Excessive covering can prevent proper development and increase the risk of rotting. Some growers do not cover the seeds at all. You can also sprinkle the pebbles over the seedlings when they are bigger.

3. Create a Humid Environment

Mist the surface of the soil with 3 % hydrogen peroxide solution, wait a few minutes and mist the soil with water using a spray so it gets wet. Be careful not to wash the seeds out. Place the pots into transparent plastic bags or a mini greenhouse to maintain a humid environment, which is crucial for successful germination. The surface of the substrate with seeds must not dry out during germination. Optionally, you can place the pot in a tray with water and allow it to soak thoroughly. Then, remove it from the water. This method will result in a very wet substrate, so it’s crucial to remove it from the mini greenhouse or plastic bag immediately after germination.

4. Light and Temperature

Place the covered sowing in a bright area, but avoid direct sunlight, as the limited space can quickly overheat. If seeds overheat, they will not germinate. A good starting point is a north-facing windowsill, where the risk of overheating is minimal. As seedlings develop, they will likely need more light, then relocation to a brighter windowsill is advisable, especially if you see signs of etiolation. Still, do not expose them to direct sunlight.

The optimal germination temperature is around 20 °C (68 °F). Cooler temperatures may slow germination, while higher temperatures can reduce success rates and increase the risk of rotting. Some sources says Conophytums germinate best when there is big difference in day and night temperatures but I have them in room with 20 °C during day and just a little lower during night (18 °C) and there seems to be no problem. However, I have them in a room with 20 °C during the day and only slightly lower at night (18 °C), and there seems to be no problem.

5. Germination

Conophytum seeds typically germinate within 1–2 weeks, with most sprouting relatively quickly. Keep the soil consistently moist but not waterlogged and check regularly for fungus. If fungal hyphae appear, remove the affected material and lift the cover to improve airflow. When using mini greenhouses, you can easily isolate an infected pot for separate treatment.

If some seeds do not sprout right away, do not discard them—certain species are more challenging to germinate and may take longer (especially Conophytum youngii and some C. roodiae forms).

6. Watering and Maintenance

Once the seeds sprout, gradually remove the plastic cover to acclimate the seedlings to lower humidity. After a few days, you can remove the cover completely. I usually do this after 2-4 weeks after seed germinated if there are no signs of fungal issues (if there are some fungal issues this has to be done earlier to avoid risk). It is important to observe the appearance of the seedlings for any signs of stress:

• Seedlings that elongate and appear pale green require more light.
• If they stay small and turn reddish-brown, they may be exposed to too much light or direct sunlight.
• If they collapse and rot, overwatering and infection is likely the cause, and they may need improved airflow and reduced watering.

Use a fine mist spray bottle to keep the sowing medium evenly moist but avoid making it waterlogged. Watering with a can can be tricky, as it may disturb the small seedlings. An alternative is bottom watering, by placing the pots in a shallow tray of water or using a base of mini greenhouse. However, this method can make the medium excessively wet for several days, raising the risk of rot. Make sure the pots absorb the water completely and do not leave them standing in excess water for too long. If you have sowings in a cold greenhouse during winter, bottom watering is not recommended because it makes the substrate too wet. In cold conditions, it takes a long time to dry out, which could lead to seedling rot.

Occasionally some seedlings rot. These should be removed immediately including their roots otherwise it can affect other seedlings around and spread rapidly in humid environment.

After about three months, an important transformation occurs. Conophytum seedlings undergo a process known as “body change.” During this time, the initial leaves gradually dry up and are replaced by the mature pair of leaves, which form the plant’s main body. In principle, to ensure the transformation is successful, watering should be limited during this time (water with small doses to ensure the plants don’t completely dry out), allowing the old leaves to dry out completely. Nevertheless, during the first year, this is not necessary, and it is better to keep the soil moist throughout the entire first year.

7. Transplanting

        Once the seedlings are big enough to be handled (or they are getting too crowded), transplant them either into individual pots (obviously they are still quite small so more plants fit into 6×6 cm pot) or group them in larger trays. I typically leave them in the original sowing container for one to two years, but the exact timing depends on factors such as the plant species, seeding density, watering habits, overall plant health, and fertilization. Use a well-draining soil mix, which can now have a coarser texture, or opt for the same mix you use for mature plants. After transplanting, strong sunlight should be avoided. They need time to root, and excessive stress can inhibit rooting.

Conclusion

Successful seed germination and plant growth require a comprehensive approach. Beyond choosing the right substrate, maintaining proper watering and temperature, other factors such as humidity, balanced lighting, and sufficient nutrients play a vital role.

It is essential to understand that these conditions interact and influence each other, creating a dynamic environment. The key for a successful cultivation lies in finding the optimal balance between all these elements, observing plants and change these conditions according plant appearance. For example, soil mixture which works well for one grower does not have to be suitable for another as other conditions are different.

With patience and attentive care, you can successfully grow Conophytum from seeds and appreciate their unique beauty in your home or greenhouse. Happy sowing!

Frequently Asked Questions (FAQs)

• When is the best time to sow Conophytum seeds? There are two different approaches: some growers sow seeds early in spring (February), while others sow in autumn (from mid-September to early October, depending on weather – when the summer temperatures are gone). But in general, if you can maintain stable growing conditions, sowing can be done at any time of the year.
• How dense shall I sow the seeds? I prefer not to sow seeds too densely, as this requires earlier transplanting or results in natural selection, where many seedlings don’t survive. To give a practical example, a 6×6 cm pot can be divided into four sections, with each section holding one portion of cono seeds (10–30 grains).
• How deep should I sow the seeds? Sow the seeds on the soil surface, covering them lightly with small pebbles. Alternatively, you can add pebbles later as the plants grow. More details are provided in the text above.
• Why are my seedlings damping off? A fungal disease can cause emerging seedlings to collapse. To prevent this, increase ventilation by opening the sowings, which helps reduce humidity. Air circulation is important, use a small fan if necessary.
• Why are the seeds not germinating? Possible reasons include poor seed quality, improper seed storage, incorrect soil moisture, unsuitable temperature, or fungal infection.
• How can I improve germination success with Conophytum seeds? Use high-quality seeds, maintain stable growing conditions, practice proper hygiene to prevent contamination, and be patient while closely monitoring your seedlings.
• Can I use this sowing method for other mesembs? Absolutely! Since these plants are closely related, they can be sown under the same conditions. However, most mesembs are more robust and grow faster, so avoid sowing them too densely. They also require more light, making spring the ideal time for sowing.
• How often shall I water Conophytum seedlings? Conophytum seedlings should never dry out completely. However, the substrate should not remain constantly waterlogged. While more water and higher humidity promote faster growth, they also increase the risk of rot and algae formation. On the other hand, less water slows down growth but minimizes issues with algae and rot. The optimal watering frequency depends on factors such as pot size, substrate, temperature, ventilation, and the growth stage. As the seedlings gets older, they can tolerate occasional slight drying. The grower’s task is to find the right balance.