Professional area | Culture factsheet | Culture factsheet | Sowing
Seed is sown in January or February for flowering to begin in September or October. They may be sown at any time of year.
Seed is sown in expanded polystyrene trays of 2cm diameter cells, in a sowing medium of young peat enriched with 500g of general NPK mix per c.m.
The use of good quality compost for seed covering is very important so that the seedling can readily free itself from the seed-coats.
After soaking, the trays are placed in a germination chamber, at 18ºC (64ºF) for 20 days.
The period of acclimatisation to the glasshouse, in the range 18ºC (64ºF) to 20ºC (68ºF), is crucial for the success of the sowing.
Mist spraying is repeated a number of times so as to soften the seed-coats.
We start watering with fertiliser at 7 weeks after sowing, using an NPK balance of 1:0.7:2 and a concentration (0.45g/litre) giving a conductivity of 0.8 mS/cm.
Cyclamen are generally propagated by seed. The seeds are not pre-treated before storage; if you wish you may treat them with dilute bleach before sowing.
It is up to the grower when to sow; sowing may be at any time of year, and the date will be chosen depending on the desired flowering date.
A 2cm diameter cell is what suits the seeds, and this must be compatible with the size of the pricking out boxes, to save labour.
The growing medium we use for sowing is from company EGO and composed as follows:
To this sowing medium we add either Biofox (1kg/c.m) or Fusaclean (200g/c.m), for biological control of the vascular wilt disease pathogen, Fusarium oxysporum.
It is advisable to cover the seed, so as not to encourage Penicillium growth.
The covering material is Klasmann seed special (reference nr080), with 500g of NP2O5K2O standard fertiliser (12-14-24) per c.m of compost.
This peat has a fine composition (particle diameter 0-5mm), but is distinguished by its relative freedom from extremely fine, dust-type particles.
The use of this seed covering allows the seed’s testa to stay in the soil, so that the cotyledon can grow unhampered. It is worth pointing out that a good seed covering can increase the number of well-developed plants by 10%.
Another alternative for seed covering is vermiculite. If this is used, then when the time comes to acclimatise the seedlings in the glasshouse there must be more mist spraying, in order to maintain a sufficient, and constant, humidity.
The growing medium should first be tamped down a little in the cells, and then lightly pressed at the centre to make a central dip which ensures that the seed will be well centred in the cells.
Using a sieve, the seed is then covered with the covering compost to a thickness of 5mm.
After sowing, the cells are watered a number of times in order to soak the medium thoroughly.
Germination takes place in a climate-controlled chamber, in total darkness and at the optimal temperature of 18ºC (64ºF); relative humidity, 90%. The temperature and humidity of the seed trays must be carefully kept constant: in order to prevent a drop in humidity, all the trays are covered with plastic wrapping.
Germination takes around twenty days to the appearance of the seedlings. The average germination rate is 85% and can be as high as 100%.
The trays are then brought out to the glasshouse.
The trays are brought out to the glasshouse and set on staging grids before the shoots are clearly to be seen. Agryl P17 fleece has been spread beforehand to cover the grids in order to maintain relative humidity.
At this stage the glasshouse temperature is slightly above that of the climate-controlled germination chamber: in the range 18ºC (64ºF) to 20ºC (68ºF).
Immediately on arrival in the glasshouse the trays are watered, though not so copiously as to encourage the growth of Pythium or Botrytis rot; then they are covered with fleece.
Covering the sprouting seed in this way enables us to keep humidity constant and high; there has to be good aeration, however, or Botrytis will appear.
2 types of fleece are used:
- the first is Agryl P17 or similar and lies directly on the shoots. It is constantly kept moist with a water spray.
- the second lies on top of the Agryl P17 and is an aluminium weave. This prevents heat loss. Moreover, 25% of the surface of this layer is left open, so as to allow a good aeration of the shoots (the arrangement has three aluminium strips followed by one clear, one that lets air through). This layer is kept on for 10 days or so; the point is that the seeds do not all germinate together: some are ahead of others, and this could cause problems at the pricking-out stage. The aluminium layer keeps the light intensity down to around 5000 lux, which is enough for the establishment of photosynthesis in the more advanced plants, but avoids letting them grow too fast: so the more backward ones have a chance to reach the same level of growth.
Mist spraying should be generous and repeated a number of times in the day so as to create a film of water under the first layer of fleece; there should not be so much water from these mistings as to encourage Botrytis, nor so little that the seedlings do not rid themselves entirely of their seed-coat. This needs to be checked, accordingly, every day.
We start watering with fertiliser at 7 weeks after sowing; the first application is when the two layers of fleece have been removed. The concentration of the nutrient solution is 0.45 g/litre, with an NP2O5K2O balance of 1:0.7:2 and resulting in a conductivity (electrical) of 0.8 mS/cm.
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