Growing Cyclamen From Seed

An authoritative new monograph, The Genus Cyclamen, has recently been published and it seemed appropriate to publish the section on raising the seed. The book is written by Christopher Grey-Wilson, the editor of the Kew Magazine, and an authority on alpine plants and cyclamen in particular. The section on cultivation from which this extract is taken was contributed by Alistar Aird and Peter Moore of the Cyclamen Society.

Cyclamen set seed best in a buoyant atmosphere with plenty of air movement. For this reason alone it may be worth putting a ventilation fan in a greenhouse. At the same time, the better air movement makes fungal disease less likely. They can also be encouraged to set seed by shaking the stems: spreading the fingers among them and twitching the hand from side to side is one way, tapping the side of the pot against the staging another, and yet another well known to people who take plants to flower shows is to take them for a ride in a car or van. A small camel-hair brush can be used to transfer pollen from one flower to another, and is especially useful for cross-pollinating different plants.

At whatever time of year the species flowers, seed generally ripens during the following summer, though later if the weather is poor. When the seed is ripe, the coiled peduncle (except in C. persicum) relaxes or sometimes pushes up the fruit-capsule slightly, and the capsule itself loses its distended look and then starts to split open, several teeth curling back from the point furthest away from the stalk.

Seed is best sown immediately it is ripe. Ideally, it should be gathered slightly before the capsule opens, and before the seed has darkened fully in colour; if it is white or ivory-coloured it is too soon, a pale honey or hazel colour is perfect. Seed can be washed to remove the sticky coating which encourages ants to carry off and 'sow' the seed in nature. Washing may also remove any germination inhibitors that may be present, though this is not really necessary if the seed is truly fresh and just short of full ripeness.

If the seed is old and dry, it should be soaked for 24 hours in warm water, to plump it up. Some growers swear by a shorter soak in warm weak detergent solution followed by a two-hour soak in fresh water, but it is impossible to conclude from reported results that this gives any real advantage.

A suitable sowing compost is one similar to that used for potting, though reducing any fertiliser, and replacing John Innes or a soil-less compost, if that is included, with the relevant seed version. Extra grit encourages vigorous rooting and makes the seedlings easier to prick out without damaging the plants.

A reliable and widely used home-made potting mix is roughly one part flake leaf-mould, one part sphagnum peat and one part sterilised loam and two parts of coarse sand. Half a teacup of bonemeal, or of John Innes Base or a similar balanced potting fertiliser should be added to each two-gallon bucket (9 litres) of this mix. A successful variation on this theme is to forget about the added fertiliser, but to replace the loam with John Innes No. 1 compost or fertile garden soil, and to use one part of sand and one part of limestone grit or mortar rubble instead of the two parts of coarse sand.

The seeds (which some people find easier to handle if rolled gently in dry silver-sand first) should be space-sown about 2-3cm apart, and covered with a thin layer of grit, oyster chips or fine stone chippings. A 5 inch (13cm) pot with a good layer of drainage crocks, small stones or Hortag in the bottom is suitable for a small number of seeds, and a larger half-pot or deep wooden seed-tray (fully 4 inches (10cm) deep), rather than the shallow ones most widely available, are better for larger quantities of seed.

When the sown pot or tray has been well-watered, it should be encased in a wire-closed clear polythene bag or covered by a sheet of glass, and put in a place where the temperature will not rise above 60F (16C), and preferably will not fall much below it. Germination should then start in a few weeks, at which time the cover must be removed and the compost kept just moist but not wet. Do not give up even if there is no sign of life for months. The seedlings should be left in their containers until they become dormant in their second year. They should be encouraged to stay in growth through the first year. This can usually be done by moving them into cool shade in spring and keeping them, and the air around them, fairly moist. If growth seems tardy then a weak foliar feed or half-strength liquid feed may be sufficient to promote more vigorous growth.