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Seed Germination Chart

Some Abbreviations Used
A: Annual - a plant which lives one year only from seed.
P: Perennial - a plant which comes back every year.
H: Indicates a plant hardy in northern zones.
T: Indicates a tender plant, shrub (sh), or tree (t) which will not winter over in northern zones.
IS: In Situ; can be planted outside directly where it is to grow.
JC: Just Cover; barely cover with soil
SS:Surface Sow; press seeds gently into to the soil to make good contact, but do not cover with any additional soil; these seeds require light to germinate.
L/D: Light or Dark; seeds which require dark should have the flat covered with newspaper or brown paper or something similar to keep light from getting to the seeds. Plants requiring light to germinate are to be surface sown.
S/I: Germination is slow and irregular
HH: Half hardy. If an annual, it will usually not reseed itself in northern zones, and if perennial, will be killed by freezing temperatures.
TP: Tender perennial (or shrub, etc). Will not winter over in northern zones, but makes a good greenhouse specimen.
GHS: Tropical or delicate plant best grown in greenhouse.
BB: Bulb.

NOTE: The heading 'Medium' refers to a sterile potting soil.

PlantDays for
Temp °FMediumDepth of
Special Info
Iliamna (hp)30-365 s/iL55-65Well-drained 1/16"#3 for 3 weeks.
Impatiens (hha)21-30 s/iL70-75Peaty SSRequires high humidity until germination
takes place. See Begonia
Incarvillea (hp)25-30.55-65Well-drained SSSee Begonia
Indigofera (hhsh)30-90 s/i.50Well-drained 1/8"#2 for 24 hours.
Indigofera (hsh)30-60.65-70Well-drained 1/16"#2 overnight; use nearly boiling water.
Inula (hp)14-45.55-65Well-drained 1/16"Can be sown IS.
Ionopsidium (ha)14-21.55-60Well-drained 1/16"Best sown IS.
Ipomaea (hha)5-21 s/i.70-85Peaty ¼"#1, then #2.
Iris (hp)30-500+ s/i.60-70Peaty ¼"May require 2 winters outdoors
before germinating. See Bonsai
Isatis (hb)14-45.50Well-drained 1/16"Best sown IS.
Ixiolirion (hbb)30-90 s/i.50Well-drained 1/16".
Ixora (tsh)30-120 s/i.70-75Well-drained 1/16"#3 for 3 weeks.

© 2001 by Ernestina Parziale