Sowing method: Cultivating Proteas and related species, compiled by Ton Vreeken. The best time to sow is in spring or autumn when the difference between day and night temperatures is approximately 12 degrees. Pre-treatment of seeds from some Protea species significantly increases germination rates and reduces loss due to fungi.
Proteas: Dissolve a disk of Smoke Primer™ (available from us) in 50 ml of warm water at 50°C and soak the seeds in it for about 30 minutes. Smoke Primer™ is a product that contains the chemical compounds from the combustion of, among other things, Protea shrubs. These substances activate seed germination. (In nature, ants and other insects drag Protea seeds underground. From time to time, Protea fields burn. The substances produced during this process penetrate the soil and are then absorbed by the seeds in nature.) Sow the seeds in a mixture of 3/4 coco peat and 1/4 silver sand and spray the seedlings with a sulfur solution (against fungus).
Paranomus and nutty seeds such as Leucadendrons, Leucospermums, Mimetes, and Serruria: A good method to break the dormancy of the seeds of these Proteaceae: Dormancy is most common in the so-called 'nut-fruited' genera of South African Proteaceae. Germination in the aforementioned species is strongly promoted by exposing the seeds to oxygen, which can be done in practice by soaking the seeds in a hydrogen peroxide solution. Furthermore, it is important that the seedlings are exposed to fluctuating temperatures during the germination period. The temperature requirements for germinating seeds of Leucospermum cordifolium and Serruria florida have been investigated: it was determined that the need for oxygen and fluctuating temperatures are independent of each other, but that each of the factors strongly influences germination. The daytime temperatures of late autumn and winter in the Western Cape are ideal for the germination of most seeds. However, there are a few exceptions.
In addition to using Smoke Primer™ (as a supplement or alternative), you can use the following method to achieve maximum results in breaking dormancy:
1. Soak the seeds in a freshly prepared 1% hydrogen peroxide solution for 24 hours in a shaded place. Remove any seeds that still float after 24 hours.
2. Sow the seeds and place them at the following temperatures: 17 hours at 8°C and 7 hours at 22°C.
It is best to sow the seeds some distance apart. Use the same sowing medium as for Proteas. Sow at a depth equal to the thickness of the seed and make the pot or seed tray well moist. Place them in semi-shade and protect them from mice, birds, etc. Water with a fine spray or plant mister and ensure that the seedlings never dry out. Once the plants are above ground, they need less frequent watering. The germination period varies from 1 to 3 months depending on the species. The cotyledons appear first, followed by the first true leaves. Once the first true leaves have appeared, the plants can tolerate full sunlight.
Transplanting: When transplanting, ensure that the fine roots are not disturbed. If the garden soil is well-drained and acidic and you live in a frost-free climate, you can plant proteas in a sunny spot in the garden. When transplanting, add some well-rotted compost to the planting hole. Proteaceae tolerate windy conditions well and prefer good air circulation around the plants. Mulching with well-rotted compost or wood chips helps control weeds, retains moisture, keeps the roots cool, and adds nutrients to the soil.
Potting soil for transplanting: If you live in the Netherlands or another country with cold, wet winters, the plants will eventually need to be transplanted into pots and kept frost-free and not too wet during winter. The soil mixture can consist of:
▸ 2 parts coarse river sand
▸ 2 parts potting soil
▸ 1 part peat moss
▸ 1 part compost
▸ 1 part vermiculite or perlite.
It is important that the soil mixture is well-drained. Vermiculite helps retain water so that seedlings and young plants do not dry out between waterings.
Nutrition for Proteaceae: Because proteaceae are adapted to nutrient-poor environments, regular fertilization with liquid chemical fertilizer will burn their delicate roots. Use an organic fertilizer such as seaweed extract, worm castings, or hemp fiber compost. A low dose of Osmocote or other enriched chemical fertilizer (with trace elements) is well absorbed by the plant. Annually sprinkle a layer of peat moss or alum on the surface to keep the soil acidic. Fungi are a serious threat to proteas. They sometimes cause plants to die suddenly due to root damage. To prevent fungal infections, it is best to keep the plants relatively dry during dry weather. Only water the plants during the cool morning hours and never in the evening. Place the pots in a tray of water for about an hour each week. More frequent watering increases the risk of rot.
A few points to note:
∙ Never let seedlings dry out during the germination period and while young seedlings are growing, as their root system is very fragile.
∙ When watering, ensure that the soil structure is not disturbed, which could damage the delicate root system.
∙ Do not use bottom heat during germination as this increases the risk of fungal infection. When germinating, do not seal off the space above the seed trays in such a way that air stagnates.
∙ Ensure that roots remain completely intact during transplanting. If the fine root system is disturbed, plants often die.
Good luck!
Vreeken's Zaden Dordrecht
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Sowing/planting time:
- March
- April
- September
- October
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