Haworthia seeds germination:
The successful germination of haworthia seeds depends on several factors. It can be difficult at first, and become very easy once you gain some experience. I hope the tips and advice below will help, however there is not one perfect recipe as it depends on so many factors. What I share here, has been learnt from other growers combined with my own experience and findings. I am still experimenting and improving my own methods every year.
Quality and viability of haworthia seeds:
Viability of Haworthia seed deteriorates quickly after around a year after harvest. Always make sure you purchase fresh seed and you are already of to a good start. Trustworthy sellers should indicate the harvesting season. Seeds approaching the age of one year will be marked down in my store and if they don’t sell will be removed and I will sell them. I still achieve decent results with seeds up to 2 years old. Good storage methods plays a part here.
When to sow haworthia seeds:
Ideal temperatures for me are a night/day range of 15-25 degrees Celsius. In my climate, this occurs during spring and autumn. Planting during other times increases risk of bad or no germination or a struggle to keep your seedlings alive. My advice for best results, check when your temperatures starts to go into this range, in South Africa probably around Sep, and again in Feb/Mar, these are your best times to sow Haworthia seed. However I have sowed quites successfully mid winter (indoor start with heat and light source) as well as mid summer (with daily temperatures consistently over 30 degrees Celsius, and minimums above 20 degrees), but you have to make the required adjustments (e.g. providing extra shade, cool area or alternative heat source (eg heatpads or heated room). If you a beginner grower, sow the seeds in different batches as this will decrease your chances of total failure. Keep a few seeds for when conditions are perfect.
Haworthia seedling germination and growing soil mix:
Each grower swears by his own soil mix and success really depends on a lot more than your growing medium. Any good draining seedling mix should suffice. If you want to keep it rreally simple use a mix of river sand (or pool filter sand) with some succulent mix/compost with most of the bigger particles sifted out or removed manually. You don’t want the little seedling to struggle rooting through a big bark particle.
I microwave the mix thoroughly before use. I add some water and put a bowl full in the microwave for around 5 minutes. It comes out steamy hot and needs to cool down before being used. I also spray with Funginex (active ingredient Triforine) directly after sowing. Fungal attacks are one of the biggest reasons for loss of seedlings. I feel that these two steps have really improved my results.
I personally use a mix adapted from the recipe provided on Gerhard Marx’s website but have had success with many different mixes. I still experiment with different mixes at this point.
A good haworthia seedling mix should have sufficient drainage and air between particles, but retain sufficient moisture.
Marc Batchelor in New Zealand (one of the best growers of haworthia seedlings in the world) currently uses a scoria and coir mix very successfully, and advises against the use of peat.
Jakub Jilemicky sows in pure perlite while Renny Wong in the USA sows in pure akadama. This shows that many soil components or mixes can work, it is how you combine this with all the other factors.
Haworthia seedling light requirements:
For me the right amount of light for haworthia seedlings is one of the most important factors for growing haworthia seedlings successfully. It is crucial to get this right as too little or too much light can lead to complete failure. Bright shade is recommended. Direct sunlight should be avoided as this can kill the seedlings or severely stunt them. Cooking some of my special haworthia seedlings during a small time of direct sunlight every day was one of my own initial mistakes. Not given enough light haworthia seedlings will grow too leggy and this can also cause longer term problems.
For me, 80% (or 2 layers of 40%) shade net over the seedlings works well, and this is inside my plant house, with already around 40-50% shade factor. Remember Haworthia prefers less light than most other succulents. Be very careful when moving your seedlings as a sudden increase in light levels can stress and stunt them or even kill them.
You will need to judge if your light level is correct by watching your seedlings develop. If they turn red, they are getting too much light. If they grow too leggy, they need more light. Be careful when you adjust to more light in the last instance, just suddenly increasing the light level is not a good idea too, you will have to change it gradually.
Providing humidity for haworthia seed germination:
Haworthia seed germination should be aided by providing a humid environment in the first few weeks. This can be achieved by using plastic or glass cover or putting the whole pot in a Ziplock bag. I have also sowed quite successfully in plastic food trays with lids. Once most seeds have germinated (normally within 3-6 weeks), remove the cover, as your seedlings now need good air circulation to prevent fungal problems.
Covering haworthia seeds when sowing:
I water the seedling mix in the pot thoroughly. Then sow the seeds on top, and cover thinly with some course particles, e.g. river sand with the fines sifted out, or aquarium sand. I personally use a fine white crush I source at a landscaping wholesale supplier, you will notice it on the images on this page. After covering, give another spray for the haworthia seeds to settle. These course particles on top provide good support the small seedlings and they really don’t struggle to work through it during germination.
Watering haworthia seedlings:
I put my pots in a plastic tray and will keep a thin level of water at the bottom of the tray for the first few weeks during germination. If you covered your pots with glass or plastic properly, you won’t even have to water again until germination, but an occasional spray won’t do harm. The soil should never dry out during this time.
When your seedlings are established after about 2-3 months I start watering from the top not less than once a week. They should just dry out and then get water again. This will depend on your own climate, seedling mix and air circulation.
If your seedlings turn red at any point they are stressed and this inhibits growth rate. Stress will mainly be from either too much light or moisture stress (dry for too long).
Some useful links:
http://www.gerhardmarx.com/p/succulent-cultivation.html Go read this article by the Haworthia master, you won’t regret it.
http://haworthia-gasteria.blogspot.com/2008/01/propagation.html I’ve personally had problems (especially moisture control and physical support to seedlings to keep them upright) by sowing in pure perlite. Jakub uses this method for producing thousands of seedlings successfully.
https://www.facebook.com/groups/236504129836114/ A group by Marc Batchelor in New Zealand, a master of growing haworthia from seed.
Putting it all together:
You will have to experiment, learn and adapt to find a method that works for you on a consistent basis.
Good luck with the germination of your Haworthia seeds and the care of your Haworthia seedlings. I find very few things as rewarding than staring at my little haworthia seedlings and seeing how the develop over time.