Deno’s Garden

Penstemon gairdneri

Genus Penstemon

This source reports 5 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Low Rated by us, not by the source.

Start around January 5, 2027 for a May 3 last frost.

  1. Cold moist stratification

    Temperature: 40°F 4°C

No stated waiting before sowing. Then 90 days to germinate.

100% germination in 90 days.

This source doesn't state how long.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. gairdneri ssp. gairdneri germ. 40(100% in 3rd m) and 70D(100/o)-40-70. A second sample germ. 70D GA-3(40% in 5-11 d), 40(64% in 6-11 w), and 70D(2%). P. gairdneri ssp. oreganus germ. 40(100% in 3rd m) and 70D(3%)-40-70.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 2

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around January 18, 2027 for a May 3 last frost.

  1. Cold moist stratification

    Temperature: 40°F 4°C

No stated waiting before sowing. Then 77 days to germinate.

64% germination in 42–77 days.

This source doesn't state how long.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. gairdneri ssp. gairdneri germ. 40(100% in 3rd m) and 70D(100/o)-40-70. A second sample germ. 70D GA-3(40% in 5-11 d), 40(64% in 6-11 w), and 70D(2%). P. gairdneri ssp. oreganus germ. 40(100% in 3rd m) and 70D(3%)-40-70.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 3

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around March 25, 2027 for a May 3 last frost.

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing. Then 11 days to germinate.

40% germination in 5–11 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. gairdneri ssp. gairdneri germ. 40(100% in 3rd m) and 70D(100/o)-40-70. A second sample germ. 70D GA-3(40% in 5-11 d), 40(64% in 6-11 w), and 70D(2%). P. gairdneri ssp. oreganus germ. 40(100% in 3rd m) and 70D(3%)-40-70.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 4

DerivedN. C. Deno, 1993

Difficulty Very high Rated by us, not by the source.

Start around December 15, 2026 for a May 3 last frost.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: dark

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

Steps after step 1 run on after germination.

about 3 months from start to sowing. Germination time not stated; 21 days assumed.

3% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. gairdneri ssp. gairdneri germ. 40(100% in 3rd m) and 70D(100/o)-40-70. A second sample germ. 70D GA-3(40% in 5-11 d), 40(64% in 6-11 w), and 70D(2%). P. gairdneri ssp. oreganus germ. 40(100% in 3rd m) and 70D(3%)-40-70.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 5

DerivedN. C. Deno, 1993

Difficulty Very high Rated by us, not by the source.

Start around March 15, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing. Germination time not stated; 21 days assumed.

2% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. gairdneri ssp. gairdneri germ. 40(100% in 3rd m) and 70D(100/o)-40-70. A second sample germ. 70D GA-3(40% in 5-11 d), 40(64% in 6-11 w), and 70D(2%). P. gairdneri ssp. oreganus germ. 40(100% in 3rd m) and 70D(3%)-40-70.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.