Soak Seeds in 3% Hydrogen Peroxide Solution (optional)
Soaking seeds in a 3% hydrogen peroxide solution before scarification can offer several advantages for germination and seed cleanliness:
- Disinfection: Hydrogen peroxide acts as a disinfectant, helping to eliminate seed-borne pathogens, fungi, and bacteria. By using this solution, you can lower the chances of infections that may interfere with germination or produce diseased seedlings.
- Oxygenation: As hydrogen peroxide breaks down, it releases oxygen. This added oxygen can benefit seeds, especially in conditions with limited oxygen availability. Oxygen plays a pivotal role in cellular respiration, an essential process during germination.
- Softening Seed Coats: The solution can assist in softening the hard seed coats of soursop, potentially accelerating the germination process.
- Stimulating Germination: Some research indicates that hydrogen peroxide can activate dormant seeds to germinate by simulating natural signals seeds would receive from environmental triggers.
Precautions to Consider
While there are benefits, it’s crucial to exercise caution:
- Duration: Avoid soaking seeds in the solution for extended periods. A typical soaking time is about 12 hours, though we are looking for more research on a suitable length of time for soursop seeds specifically.
- Concentration: It’s vital to use a 3% solution. More concentrated solutions might be too intense and could harm the seeds.
- Rinse After Soaking: After soaking, it’s recommended to rinse the seeds with clean water to wash away any remaining solution. You can then soak the seeds in warm water as above.
Scarify seeds
Annona muricata has a hard seed coat that benefits from scarification. Use fine sandpaper or a foot scrubber to etch away the hard seed coat along its side seam. Stop when you see a lighter colour underneath.
Warm water soak
Our seeds are commercially supplied and well dried to avoid mould/fungal activity. Soak the soursop seeds in warm water for at least 24 hours. Having scarified the seeds, the water can now penetrate into it and start the germination process.
Planting Medium
Use a well-draining soil mix, such as a mix of peat moss, perlite, and vermiculite in equal parts. You could also use the larger jiffy peat pellets available from garden centres.
Planting Depth
Plant the seeds about 1 cm deep into the soil.
Position & Lighting
Place the pots in a warm, shaded area. While the seeds are germinating, they don’t require direct sunlight, but they do need warmth. Ideal temperatures for germination are between 25°C to 28°C. In NZ, especially outside of summer, this might be best achieved with a heat mat depending on what warm spaces you have available.
Watering
Keep the soil consistently moist, but not waterlogged. Using a spray bottle can be effective to ensure the soil stays damp without overwatering.
Germination Time
Soursop seeds typically take between 15 to 30 days to germinate. Be patient and avoid disturbing the soil during this period.
Transplanting
Once the seedlings have grown 2-3 true leaves (not counting the initial sprout leaves), they can be carefully transplanted to a bigger pot.
Note: Soursop trees prefer a warm humid climate and well-draining soil. They are sensitive to prolonged cold temperatures, so ensure they are protected during cooler weather. Please see Grow Soursop in NZ: Tips & Tricks for Planting and Caring for Annona Muricata for more information.