Germination Guide Overview
This guide provides recommendations for germination of over 7300 seeds listed in the seed exchange of the Ontario Rock Garden & Hardy Plant Society, accumulated since 1995. For each species, a single germination technique has been chosen from several successful approaches for dry seed stored 6 months @ 20°C, except where noted.
While this data is based primarily on the experience of ORG&HPS members, we have also relied extensively on methods described by Norman Deno (Seed Germination Theory and Practice), Dr. Pavel Slaby ( www.kadel.cz/flora ) and Tom Clothier ( http://tomclothier.hort.net). We are continuing to collect complete data on many species.
If you have suggestions for improving this guide or additional information about germination please let us know.
| WHAT OUR TEMPERATURE DESIGNATIONS MEAN | |
| 4°C | Either place seeds outdoors to be exposed to a wide range of winter temperatures including freezing or put them in a refrigerator (not a deep freezer). |
| 10°C | Either place seeds outdoors in spring or fall or choose a very cool indoor location. |
| 20°C | Either place seeds in a sheltered outdoor location in mid to late spring or grow at room temperature. |
| SYMBOLS | |
| * | This species needs special care as described. |
| ? | We have no information on the germination of this species. We sometimes provide an educated guess about which approach you should try. Let us know what is successful. |
| ! | Sow immediately. The viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience. |
| LETTERS | |
| A | Sow @ 20°C. Seed germinates within 3 months. |
| B | Sow @ 20°C. If seed does not germinate within 3 months, try 4°C for 1-2 months, then 20°C again. |
| C | Sow @ 20°C for 3 months, then place @ 4°C for 3 months. |
| D | Use repeated cycles of 20°C, then 4°C for 3 months each. Germination is very prolonged. |
| E | Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. |
| F | Sow @ 4°C. |
| G | Sow @ 4°C for 3 months, then place @ 20°C for 3 months. |
| H | Use repeated cycles of 4°C, then 20°C for 3 months each. Germination is very prolonged. |
| J | Sow @ 4°C for 3 weeks, then place @ 20°C. |
| K | Sow @ 10°C. |
| L | Expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. |
| M | Store seed in moist medium @ 4°C for 3 months, then @ 20°C until radicle appears. Repeat cycle until leaf appears. |
| N | Sow directly in garden. |
| NUMBERS | |
| 1 | Resents transplanting. |
| 2 | Requires darkness. |
| 3 | Requires light or the small seeds should be surface sown. |
| 4 | Germination is improved by using GA3. |
| 5 | Germination is successful only when GA3 is used. |
| 6 | Requires scarification. Nick or rub between sheets of sandpaper. |
| 7 | Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and water used for soaking. |
| 8 | Pulpy coat inhibits germination. Remove by soaking and rinsing in clean water daily for 7 days. Discard water. |
| 9 | Tails may inhibit germination. Remove them. |
| GA - 3 | GA-3 has been shown to promote germination of a few species. Its use is described in Seed Germination Theory and Practice by Norman Deno. A Canadian source is www.gardensnorth.com |