Many species are not available as bulbs, and even if they are, some countries restrict your ability to import bulbs. So raising bulbs from seeds is the best way to both obtain and increase the number of bulbs. The information found on this page is the collective experience of PBS forum members collected over the years and it is meant as a resource for bulb enthusiasts who want to grow from seeds.
There are two types of seeds: the dry seeds of many genera and the fleshy seeds of some amaryllids. Seeds can be grown in any type of container, including recycled plastic or styrofoam drinking cups. A seedling mix, generally of 1:1 sand (or perlite) and peat based seedling mix tend to work well for most type of seeds. Some seeds need to be sown on the surface whereas others need to be covered up. Some require a cold stratification and others may need fluctuation in temperature to germinate. All seeds have a viability period which may last just a couple of months to many years. The fleshy and recalcitrant seeds of amaryllids need special handling (see below).
The number of seeds sown per pot depends on the size of the pot, the size of the seeds, and how fast the bulbs grow. Michael Mace likes sowing about 9 seeds per drinking cup container. Sowing the seeds too close together may cause the seedlings to be overcrowded and in some species can cause damping off. The seeds will start sprouting from 2 weeks to 3 years, depending on the species and seed treatment.
Once the seeds sprouted, keep them protected from extreme weather conditions, snails and slugs, and fungi. Grow the seedlings according to the species requirements. Some may go dormant the first year, others may not. It is generally a good idea to fertilize the seedlings with a dilute high P low N fertilizer. This treatment works very well in some species (like Calochortus) but does not affect the growth rate in other species. When the bulbs go dormant, stop watering and store the containers in a cool dry place. Summer dormant species respond well to warm storage whereas winter dormant species respond well to cool storage.
Allow the seedlings to grow for at least two seasons before repotting the bulbs during their dormancy. Disrupting the seedlings too soon can be detrimental to the plants.
Norman Deno:
Seed germination, theory and practice
First supplement to the second edition of Seed germination theory and practice
Second supplement to Seed germination theory and practice
UC Botanical Garden
Ontario Rock Garden society
Tom Clothier
Jane McGary's excellent article on how to grow bulbs from seeds (PDF) which originally appeared in a NARGS bulletin
PBS discussion thread on growing bulbs from seed
Breaking dormancy in seeds (how to make them grow when they refuse)
Seed collection methods (PBS forum discussion)
Raising bulbs from seeds in a hot dry climate
Flotation (floating seeds on water to help them sprout)
These notes were compiled by Mary Sue Ittner from bulb discussions forums.
By Genus
by General Category
Amaryllids - All the fleshy amaryllids (including Amaryllis, Brunsvigia, Crinum, Boophone, Cybistetes, Nerine, Crossyne, Clivia, Gethyllis, Hessea, Strumaria plus a few others are ephemeral, or recalcitrant as they are more commonly known. It is not that the seeds do not last long, it is more that they cannot prevent the germination process, so will germinate even if conditions are inappropriate. The seeds ripen within days to a few weeks after the flowers have been pollinated, and the seeds then begin to germinate within days and produce a root first. The root sometimes develops while the seeds are still in the capsule (Rachel Saunders).
Once harvested, allow the seeds to germinate in open air or in a paper envelope. Sow the seeds immediately onto a well drained mix (1:1 organic:inorganic). Ungerminated seeds should not be covered by the medium because they need light to germinate. If covering is necessary, a portion of the seed should be exposed to light. If you received material from overseas, most of the seeds will have sprouted by the time they arrive. Sow these immediately, using a pencil to make a hole which accommodates the radicle. The seed should still remain on the surface. Some seeds will only produce a tiny bulb which then goes dormant, others will continue to grow for the duration of the growing season.
If you live in the Northern Hemisphere and order amaryllid seeds from South Africa, they will arrive at exactly the wrong time for planting. You have two choices: plant them anyway, and do your best to keep the seedlings from dying in the heat of summer; or store them in the refrigerator in a sealed plastic bag. This can delay sprouting for a few months until the fall. Both approaches have risks, so if you have seed to spare it's a good idea to divide them into two lots and try both approaches (Michael Mace). Some growers have good luck sowing the seeds immediately and keep the plants growing in an air conditioned room under bright fluorescent light.
For special genera like Haemanthus, Scadoxus, and Clivia, the colorful fruit coat must be cleaned before sowing. Seeds sown without this treatment have poor germination.
Australian geophytes The seeds can then be soaked for 24 hrs in a 10% solution of liquid smoke solution (not the cooking type). With luck, you'll get germination in many of our more difficult taxa. A lot of the "lilies" are still recalcitrant after this (or even GA treatment) a combined smoke and temperature treatment may be necessary for many species. A useful treatment of smoke followed by cool and wet simulates the WA or southern Aussie winter rains when most of these taxa germinate (John Conran).
Oncocyclus Iris Seed may take up to about 5 years (some say 7 years) to break dormancy. Soak the seeds in hot water for few hours and stratify them in the fridge for a month or two before sowing. These seeds germinate very well in the first year and viability drops in subsequent years. I have observed that second, third and even fourth year seeds, if disturbed or "transplanted" to another pot, would improve germination (Dennis Tsang). The Oncocyclus specialists have developed some elaborate techniques of chipping and treatment with gibberellic acid. For more information, contact the Aril Society International.
South African (non amaryllids, winter growers) South African non amaryllid winter growers need a marked difference in day and night temperatures to get good germination. Some require smoke treatment as well. I get the best germination with fresh seed (Marc Hachadourian).
In certain climates, sowing in spring does work although not as well as autumn sowing. However, the plants will be 6 months out of synch with their normal growing cycle. At this point, the seedlings can be grown and you can prevent them from going dormant through artificial means. Otherwise, allow them to grow for a season or two in their wrong cycle and adjust them to their normal cycle as if they were bulbs coming from the Southern Hemisphere (Ian Black).
South African Irids Seed viability - many of the Iridaceae, particularly those with hard coats, last for years, and we have sown 8 year old Dierama seed with excellent results (Rachel Saunders).
Barely a geophyte
Dodecatheon Sow the seeds and keep them about 4C (40F = refrigerator temperature) for 1 month, followed by warmer temperature. Some species will germinate without a cold period, but most require a short one. Since they are so small for quite a while and have fairly delicate roots, the safest bet is to sow them thinly into pots with clean and fast-draining soil and plan to keep them in the pots for a year. Shooting stars sometimes tend to germinate erratically and also can decide to "wait" a year, so keep the pots even if nothing happens this year and you may see results next year (Louise Parsons).
Lapageria rosea The seeds are easy to germinate and require no special treatment other than moisture and cool temperatures (~10-15 degrees C). The plants do not seem too fussy about potting mix, although something open and a bit acid seems to be preferred (John Conran).
Xerophyta Seeds can be very small sow sowing on the surface gives better results (Will Ashburner). Xerophyta viscosa germinates in 8 weeks when surface sown in spring. Winter sowing takes 18 weeks.