Lily Germination

Photo by David Pilling shows hypogeal germination of Lilium superbum; notice bulb and root formation with no leaf.

Is where a seed germinates reasonably quick at temperatures of about 18 °C. (65 °F.) and upon germination sends up a cotyledon which is followed shortly by true leaves. Some lilies can germinate and send up a cotyledon within nine days of planting; others can take over ninety days to do so. Lilies that take a long time to germinate and send up a cotyledon generally take another forty five to sixty five days before they start sending up true leaves. Lilies that germinate quickly will generally start sending up true leaves within thirty to forty five days.

Some lily species will germinate reasonably quickly but the cotyledon will die back before any true leaves are put forward. For these, upon the cotyledon die back, give them a three month cold period (can be longer) at 2 °C.(35 °F.) When planting out after the cold period, they will send up true leaves in about three weeks. After ensuring the planting medium is quite dry, I simply encase the four and a half inch geranium pot which I grow the seedlings in in a zip-lock baggie, seal the baggie and place it in the lily fridge.

Is where a seed germinates only after an extended length of time in a reasonably warm just moist incubation period followed by a cold period. Some species may even require a second warm period to germinate and a second cold period before they sprout their cotyledon. These alternating warm cold periods are around three months each, but can be longer. Some specie types that have this form of germination have varieties that germinate as immediate epigeal.

Is where a seed germinates in temperatures around 18 °C. (65 °F.) and the cotyledon never grows above the soils surface. Some of the lilies that germinate in this manner will send up their first true leaves within 30 to 45 days of planting. Other lilies can take 6 months or more. No cold or dormant period is needed by this type of lily before they send up true leaves.

Is where lilies require cool temperatures of 9 °C. (48 °F.) to 11 °C. (52 °F.) to germinate and send up their first true leaves. Lilies that require this type of germination conditions may never germinate if held at other temperatures.

Is where a lily seed germinates at temperatures of around 18 °C. (65 °F.) in dark conditions. After a three to four month incubation period and before they will send up true leaves, these lilies require at least a three month cold (dormant) period at a temperature right around plus 2 °C. (35 °F.). I have found that delayed hypogeal seeds which are given a four month incubation period have more foliage growth their first summer and much better first winter survival rates then delayed hypogeal lily seeds that are given only a three months incubation period. The ones that receive a four month incubation period also come to flower a year or two ahead of the ones given a three month incubation period.

Inside this group (delayed hypogeal) there are species where seeds from the same pod will germinate as immediate as well as delayed hypogeal. Some years from a lily that should be delayed hypogeal germination I have had up to seven percent of the seed germinate as immediate hypogeal, other years as low as a half a percent. The delayed hypogeal seedlings that germinate as immediate hypogeal usually out grow their siblings and flower a year or two earlier thus they are well worth watching for when germinating delayed hypogeal lilies. Depending on which species it is delayed hypogeal germinating lilies can take three to seven years from seed to first flower.

1 - Direct outdoor sowing
Depending on your climatic zone ratings good germination rates can be had by direct sowing about a week before your spring's last expected frost date. Plant the seed 1/8th to 1/4 inch deep and keep the soil moist. In my zone 1 Canadian scale very few immediate epigeal lily seedlings mature enough in one growing season from directly planted seed to survive their first winter. Using this method the immediate epigeal seedling survival rate for me is one out of twelve.

2 - Direct sowing in pots under lights over the winter
The soil I use for starting all of my lily seedlings is our regular top soil, very high humus, well draining, 6.5 ph. For lilies that require an alkaline based soil I amend this soil with the addition of lime. Other planting mediums can produce good results as evidenced by other people's success but I can't comment on these other mediums as I have never used them. The draw back with the soil I use is it does grow a covering of peat moss which can prove difficult, if not impossible, for late germinating seeds to push the cotyledon through it. The same difficulty can be had by the first few true leaves a seedling sends up. The growing of peat moss on the pots can be controlled somewhat with a thin coat of canary or budgie gravel placed over the planting medium's surface.
I plant nine* seeds 1/4 inch deep per each four and a half inch geranium pot. Very seldom do all nine germinate, plus there is generally some loses upon planting out and some first year winter kill. But even if there isn't any losses nine seedlings can grow in this crowded condition quite comfortably until the fall of their first flowering. When planting the seedlings out, do not disturb the bulblets or root system, to do so sets the first flowering back at least one full year. If planted as per my system, most immediate epigeal seeds planted in November of 2006 will flower for a first time in 2008.
Just prior to planting the seeds an initial watering is done in a manner that will totally saturate the planting medium. After that they get watered every second day, but not to a saturation point. Starting three weeks after the first true leaves have been sent up a fertilizing program is embarked on. Using 10-10-10 or 20-20-20 water soluble fertilizer at one half the manufacturer's recommended dosage for indoor plants, the seedlings are fertilized once every three weeks. If your seedling's true leaves start yellowing, it is usually caused by over watering. Once the seedlings get planted out there is no further fertilizing for that growing season.
For my growing conditions planting the seeds in early to mid November gives me the best results for first winter survival rates. Planting the seeds a month earlier and the seedlings get too large by the time they can be planted out; planting a month later and my first year's winter kill increases substantially. To fine tune your planting time some experiential sowing should be conducted and detailed records of the results kept. People in zone 2, Canadian scale, have good first winter survival results planting their seeds in early January, in zone 3, Canadian scale, people have good first winter survival results planting in late February early March. My seedlings are planted out starting the day following our last expected frost date, June 12th. Using this method of planting my immediate epigeal first winter seedling survival rate is eleven out of twelve.
Note * For any new cross that has been tried by me the initial planting will only be nine seeds, other seeds from the cross will be frozen as back up. Once the seedlings flower if I like the results more of the seeds will be planted, if I don't like the results, the remaining seeds may never get planted.

3 - Zip-lock baggie sowing
Using this system for immediate epigeal germinating seeds the initial seed sowing is less work but over the long run it is more work. However with this system you will know every seed in your pots are growing when you pot the germinated seeds up. Thus I generally only pot up seven seedlings per four and a half inch geranium pot.
When sowing place a hand full of planting medium in a zip-lock baggie, make it just moist by dribbling in a little water. Once you are satisfied with the moisture content of your planting medium drop your seeds in on top of the medium, seal the baggie, roll it up and lay under lights. Keep a watch on the baggie contents to ensure mildew isn't growing and to catch your seeds once they germinate. If your planting medium is too wet, the seeds will swell but will not germinate. Instead they will simply disappear. If condensation forms on the inside of your baggie it is a sign that your planting medium is too wet. Two to three days after a seed has germinated pluck it from the baggie and pot it up with the cotyledon exposed to the light. In this type of planting ensure your potted medium which the seedlings will be planted in is moist but not saturated. The advantage for me with this system is all the seedlings which are potted are up and growing before any peat moss starts to form on the planting medium's surface in my pots; in many cases the first true leaves will also have started to surface before the peat moss grows. Plus the seeds generally germinate a bit quicker in a baggie verses planting in a pot.

This type of germination pattern I have found to be the most problematic. The only way I have managed to germinate these seeds is as follows.
Prepare a zip-lock baggie as per immediate epigeal germination above except with these kind of seeds you want to ensure they are embedded in your planting medium, not on top of it. This seems to help prevent the seeds from rotting. Place the baggie under lights or in the dark at temperatures of about 18 °C. (65 °F.) for a three to four month incubation period. Check on them periodically to ensure your baggie isn't growing a mildew culture and to provide an air change. After this incubation period give them at least a three month cold period at about 2 °C. (35 °F.) then plant them out. Ensure you plant any ungerminated seeds as well as those that have germinated. About three weeks after being planted out any seeds that had germinated will send up their cotyledon. Those that had not germinated will germinate through the summer and send up their cotyledon the following spring.

Another method that works for some delayed epigeal species that won't germinate by the warm cold method is as follows. After drying the seeds freeze them for a couple weeks. Remove from the frozen situation and thaw, place in a moist zip lock type baggie under lights for seven days at room temperatures. After the end of the seven day period move the baggie to temperatures around +2 to +4 °C for six to eight weeks. At the end of six weeks move them to temperatures of +9 to +11 °C. They will start germinating within two to four weeks of being placed in the warmer temperature. It seems reasonably fresh seed only needs the six week period at +2 to +4 °C to start germinating once moved to +9 to +11 °C., while older seeds need the eight week cold period.

Plant these seeds using any of the methods for immediate epigeal germination. The results will be much the same except it is a true leaf that appears above the soil not a cotyledon. If using the zip-lock baggie method, the germinated seeds should be left in the baggie until the true leaf sprouts, but must be potted up soon there after.

1 - Direct sow outdoors
Plant the seeds about 1/4 inch deep three months or a bit more before the first frost that will penetrate your soil's surface. Keep the soil moist throughout the summer watering as required to do so. They following spring your seeds will send up their first true leaf. I get excellent germination rates using this method but the first winter after they have had a summer’s growth above ground my losses are extremely high. In a higher zone rating the losses would probably drop significantly.

2 - Zip-lock baggie planting
Prepare a baggie as per the immediate epigeal germination process except make the planting medium a little wetter. Drop your seeds on the planting mediums surface, seal and roll up the baggie, then place under lights at 18 °C. (65 °F.) for a maximum of five days or until the seeds start to swell up which ever comes first. Once the seeds start to swell up, you have to get them out from under the lights and lower the baggies moisture content or you will lose the seeds. While under lights your planting medium should be damp enough to cause a bit of condensation to form in the baggie, (a friend of mine labeled this cold steam when he first tried this method).
After the five day or seed swelling incubation period under lights, lower the moisture content in your baggie by adding a little more dry planting medium and place the baggie in a fridge set at 9 °C.(49 °F.) to 11 °C.(52 °F.). Should condensation continue to form in the baggie after they are place in the fridge continue to lower the baggie's moisture levels by the addition of more dry planting medium. Alternatively you can leave the baggie open for a day or two in the fridge or seal a Kleenex in the baggie and remove it a couple hours later. During the time period your baggies are in the fridge check them weekly to provide an air change and ensure mildew isn't growing.
Every two and a half weeks warm your seeds up at room temperatures for a twelve hour period then return them to the fridge. I do this by unplugging the fridge and leaving its door propped open. You should start getting germination within thirty to thirty five days but even when they have germinated leave them in the baggie in the fridge. Only after your seeds have sprouted a true leaf and have started to develop roots can they be potted up under lights. A bulblet that has roots but no leaf or a leaf and no roots will be lost if it is potted up. This can take four months maybe longer from the time of germination.
Once potted up they can be grown under lights until it's time to plant them out. Ensure to harden them off before planting them out. If you don't, the sun will scorch them and your seedlings will be lost.

1 - Zip-lock baggie germination
Prepare your zip-lock baggies and treat them exactly the same as the immediate hypogeal cool germination process for the first five days. After five days or when the seeds start to swell, whichever comes first, lower your moisture content in the baggies and place them in a dark area that is around 18 °C. (65 °F.). If your moisture content is too high your seeds may never germinate. Once a week check your baggies to ensure no mildew is growing and provide an air change. After a three to four month incubation time period (so long as the seeds have germinated), give the bulblets at least a three month, or longer, cold (dormant) period at temperatures of 2 °C. (35 °F.). I use the four month incubation time period as the resulting seedlings do far better then those given a three month incubation period. Three weeks before your last expected spring frost date remove the bulblets from their cold period and plant them about 3/4's of an inch deep. From date of planting the bulblets out until the first true leaves start poking through the soil will be about three weeks. Some types of lilies that germinate as delayed hypogeal are very slow to germinate; those ones should be given the three month incubation period counting from the time the given seed lot started to germinate, not from the time they were planted.

2 - Direct planting
Three to four months before the frost will penetrate your soil's surface plant your lily seeds about 1/4 inch deep. Throughout the summer keep the soil moist. The following spring your bulblets will send up their first true leaves. First winter's survival rate after the first sprouting will vary from one species to the next. For example, using this planting system in my area, L. martagon, L. canadense and L. tsingtauense have excellent first winter survival rates; L. hansonii and L. michiganense have poor first winter survival rates. So if you're not sure about your winter conditions and have a limited supply of seeds it is best to plant using the baggie method. That way you can ensure your seedlings have a little more maturity before they have to face their first out door winter.

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