Kalanchoe
Kalanchoe · Widow's-thrill
About the plant
What it is and where it grows — not part of any germination protocol.
Safety
- Toxicity
- Medium severity. All parts. Bufodienolides.
The plant
- Note
- Deno worked with garden hybrids rather than a named species, so these results are genus-level.
Toxicity is noted only where a source states it. No note here is not a finding of safety.
Sources: Seed Germination Theory and Practice, 2nd ed. — N. C. Deno; Extension Gardener Plant Toolbox — NC State Extension.
This source reports 5 treatments. All are shown.
Protocol 1
DerivedN. C. Deno, 1993Difficulty Moderate
Start around March 15, 2027 for a May 3 last frost.
Gibberellic acid soak
Sow and cover
Temperature: 70°F 21°C Light: dark
No stated waiting before sowing. Then 21 days to germinate.
42% germination in 21 days.
The best of the five. Deno's seed was garden hybrids, not a named species.
Protocol 2
DerivedN. C. Deno, 1993Difficulty Moderate
Start around March 15, 2027 for a May 3 last frost.
Sow on the surface — do not cover
Temperature: 70°F 21°C Light: light
No stated waiting before sowing. Then 21 days to germinate.
34% germination in 21 days.
Light nearly triples the plain dark result. Deno's seed was garden hybrids, not a named species.
Protocol 3
DerivedN. C. Deno, 1993Difficulty High
Start around March 15, 2027 for a May 3 last frost.
Sow and cover
Temperature: 70°F 21°C Light: dark
No stated waiting before sowing. Then 21 days to germinate.
13% germination in 21 days.
Dark and nothing else is the weakest route that works at all. Deno's seed was garden hybrids, not a named species.
Protocol 4
DerivedN. C. Deno, 1993Difficulty High
Start around December 15, 2026 for a May 3 last frost.
Cold moist stratification
Duration: 90 daysTemperature: 40°F 4°C
Deno gives no length for this period; three months is his standard cycle.
Warm moist stratification
Temperature: 70°F 21°C Light: dark
about 3 months from start to sowing. Germination time not stated; 21 days assumed.
6% germination.
Cold first costs most of the packet. Deno's seed was garden hybrids, not a named species.
This source doesn't state how long.
Protocol 5
DerivedN. C. Deno, 1993Cold moist stratification
Duration: 90 daysTemperature: 40°F 4°C
Deno gives no length for this period; three months is his standard cycle.
Warm moist stratification
Temperature: 70°F 21°C Light: light
about 3 months from start to sowing.
0% germination.
Light helps at 70 and hurts after cold: nothing here, against 6% in the dark.
This source doesn't state how long.