In our previous article, we discussed how to go about pollinating Haworthia in order to encourage them to produce seed. The next step would be sowing and germinating these seeds. In this blog, we will describe our sowing process step-by-step. We will also delve into finer details about a variety of other factors. Keep in mind that this process can be a bit of a challenge with a learning curve. In this article, which is part 2 of our ‘Breeding Haworthia‘ series, we will discuss in depth techniques we use to germinate our Haworthia seeds.
When to sow your Haworthia seeds
The first thing to think about when sowing seeds is the timing. At Living Desert Plants, we generally sow our Haworthia seeds from September until November, and March until May. This is during the spring and autumn months, which Haworthia seedlings prefer to germinate in. This will allow the seedlings to grow a bit stronger before the heat of summer and cold of winter set in. If they are sown in June – August, it is already a bit too cold to grow Haworthia from seed. During December – February, it is too hot for the seedlings to thrive after germination. Keep in mind that the months mentioned above are for South Africa, and your ideal times may differ if you are in the northern hemisphere.
The process of sowing your Haworthia seed
The first physical step when you grow Haworthia from seed is to prepare your soil mix. We use a standard germination mix from Culterra, mixed with some extra perlite. The pot should be filled to about 0.5cm from the lip. Do not fill it any less than this, otherwise the seedlings tend to struggle. Make sure the soil is thoroughly soaked. We use freshly boiled water to soak the soil once it is in the pot, as this removes any unwanted bacteria.
You will also need some ‘topsoil’ in the form of fine stones or fine Hyuga Pumice. This is to keep the seeds in place, and to provide some extra stem reinforcement once they have germinated. Place the stones in a separate pot, and soak with more boiling water. Leave the soaked soil and stones to cool for at least 1 hour before continuing.
After everything has cooled, gently spread the seeds out over the soil surface. Make sure to sow them relatively close together. The seedlings do not have strong root systems initially, and will benefit from having other seedlings near them to help keep them upright. We find that they prefer being clumped together. Now, take the stones or Hyuga Pumice, and carefully cover the soil with a thin layer of it.
The final step is to spray the top of the soil with diluted 30 volume hydrogen peroxide. You can use half water and half hydrogen peroxide for this. Using this ensures that any remaining harmful fungi are removed from the seeds and soil. Hydrogen peroxide is not harmful to seeds or plants at all.
Germinating Haworthia seed
In order to actually germinate Haworthia seed, there needs to be plenty of humidity. To increase the humidity, place the pot in either a humidity dome or a ziploc bag. You can keep this completely closed until about half of the seeds have germinated. You should then open it for a few hours every day to give the seedlings fresh air. Make sure to keep an eye out for fungus growth after you open it for the first time.
Other things to keep in mind when growing Haworthia from seed
Sterilize everything
It is extremely important to sterilize everything you are using, including the pot, soil, and humidity dome or ziploc bag. If you do not do this, the chance that fungus will form in the hot and humid environment is high, and you will lose your seedlings. As mentioned previously, you can use boiling water and hydrogen peroxide to do this.
Soil mixture
When sowing Haworthia seeds, it’s important to use a soil mixture that will provide adequate moisture and support for the delicate seedlings. A good soil medium for Haworthia seeds is a mixture of fine coco peat and pumice or perlite, in a ratio of 60:40. The soil should be moist but not waterlogged, so add water sparingly until the soil is evenly moist.
If you are in South Africa, Culterra Professional Germination Mix is a good soil to use and is readily available at most retail nurseries.
Water & humidity requirements
Haworthia seeds need to be consistently moist and humid in order to germinate. To avoid over-watering, it’s best to mist the soil with a spray bottle or use a humidity dome to keep the soil surface moist. Once the seeds have germinated, it’s important to not over-water, as young Haworthia plants are susceptible to root rot. Water the soil when it feels dry to the touch, but avoid letting the soil dry out completely.
Light levels
Haworthia seedlings need bright, indirect light to grow. When growing this genus from seed, it’s best to provide the young plants with bright, indirect light, or keep them under strong (80%) shadecloth. After about a year, the seedlings will be strong enough to move into somewhat brighter conditions.
Fertilizer
Haworthia seeds do not need fertilizer to germinate, but once they have sprouted, they will benefit from a highly diluted fertilizer solution. Pokon Cactus Liquid fertilizer is a good option.
Once the seedlings have a few leaves, you can start fertilizing them every two weeks with a 10% strength solution of a balanced fertilizer. As the plants mature, you can gradually increase the strength of the fertilizer solution.
In conclusion, sowing and germinating Haworthia seeds requires the right knowledge and attention, including a well-draining soil mixture, consistent moisture levels, a fungus-free environment, bright indirect light, and diluted fertilizer.
Two year old plants grown from seed by Harry in the LDP greenhouse.