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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
Ramonda (hp)30-60 s/iL55-60Well-drained SS.
Ranunculus (hp)30-90 s/i.50Well-drained 1/16".
Raoulia (hp)30-90 s/iL55-60Well-drained SS.
Ratibida (ha,hb,hp)21-45.70-75Well-drained 1/8"Reduce temp at night.
Rechsteineria (tbb)30-60.70Well-drained JC.
Rehmannia (h/hhp)21-40L60-65Well-drained JC.
Reseda (ha,hb)5-21L70 Well-drainedSSResents transplanting.
Rheum (hp)21-45.60-65Peaty 1/8".
Rhodanthe (hha)14-30.75-80Well-drained JCCan be sown IS.
Rhodochiton (hhp)12-45 s/i.60-65Peaty JC.
Rhododendron (hsh)50-90 s/iL55-60 Acid peatSSGrow on in shade.
Rhodohypoxis (hp)30-90 s/i.50Well-drained JCMedium must be lime free.
Rhodotypos (hsh)365+ s/iL55-65Peaty JC#4; 3 months at 70ºF, followed by 3 months cold,
then followed by 3 months at 70ºF.
Rhoeo (tp)14-60.65-70Peaty JC#2 for 30 minutes.
Rhus (hsh)30-90 s/i.65-70Well-drained JC#1 or #2.
Ricinus (hha)15-21.70-75Peaty ¼"Seeds are poisonous.
Robinia (ht)7-30L65-75Well-drained SS#2 in hand hot water.
Rochea (hhp)14-45L60-70Peaty SSSee Begonia
Rodgersia (hp)12-60L55-60Peaty SS.
Rosa (hsh)30-365+ s/iL55 Well-drainedJC#3 for 3 months.
Roscoea (hp)30-365 s/iL50-55Well-drained SS.
Rothmannia (hhsh)30-90 s/i.70-75Peaty 1/8"#2 for 5 hours.
Rudbeckia (hha,hp)5-21L70 PeatySS.
Rudbeckia fulgida (hp)5-21L70 PeatySS#3 for 2 weeks.
Ruella (hp)30-60 s/i.65-75Peaty JC.
Ruta (hp)30-45.60-65Well-drained JC.

© 2001 by Ernestina Parziale