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Dietes grandiflora

African Iris · Butterfly Iris · Fairy Iris · Wild Iris

Family IridaceaeGenus Dietes

A white flower of six spreading tepals, three marked with a yellow blaze, around a violet center
FlowerRojer WisnerCC BY 2.0

About the plant

What it is and where it grows — not part of any germination protocol.

Habit
perennial or rhizomatous geophytePlants of the World Online
Flower
WhiteWikipedia
Native range
Cape Provinces, KwaZulu-NatalGBIF Backbone Taxonomy

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Plants of the World Online — Royal Botanic Gardens, Kew; Wikipedia — Wikipedia contributors; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Worth knowing

  • Fortnight lily is common in gardens in its native South Africa, where it is often planted in public gardens, around commercial premises and along roadsides. Wikipedia: Dietes grandiflora

Two sources report 9 treatments between them. All are shown.

Protocol 1

DerivedN. C. Deno, 1998

Difficulty Low Rated by us, not by the source.

Start around March 2, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 1, 2026.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: light

about 12 months from start to sowing. Then 35 days to germinate.

86% germination in 35 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Dietes p. 29Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora data is now more complete. Light is required for germination. Seeds germ. 70L(100% in 2-5 w), 70D(15%), 40-70D(7%), and 40-70L(40% in 2-4 w). When the sample in 70D was shifted to 70L, 70% germ. in the 4th w. Two other samples gave identical results. Seeds DS 1 y germ. 70L(80% in 1-7 w) and 70D(20% in 2-9 w), and seeds DS 2 y germ. 70L(6/7 in 5th w) and 70D(2/8 in 5th w) showing no significant dying or change in the light requirement.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Dietes p. 29. 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, 1998

Difficulty Low Rated by us, not by the source.

Start around February 16, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on February 15, 2026.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: light

about 12 months from start to sowing. Then 49 days to germinate.

80% germination in 7–49 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Dietes p. 29Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora data is now more complete. Light is required for germination. Seeds germ. 70L(100% in 2-5 w), 70D(15%), 40-70D(7%), and 40-70L(40% in 2-4 w). When the sample in 70D was shifted to 70L, 70% germ. in the 4th w. Two other samples gave identical results. Seeds DS 1 y germ. 70L(80% in 1-7 w) and 70D(20% in 2-9 w), and seeds DS 2 y germ. 70L(6/7 in 5th w) and 70D(2/8 in 5th w) showing no significant dying or change in the light requirement.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Dietes p. 29. 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, 1998

Difficulty Moderate Rated by us, not by the source.

Start around December 8, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

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

about 3 months from start to step 2. Germination happens during step 2, in 28 days.

40% germination in 14–28 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Dietes p. 29Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora data is now more complete. Light is required for germination. Seeds germ. 70L(100% in 2-5 w), 70D(15%), 40-70D(7%), and 40-70L(40% in 2-4 w). When the sample in 70D was shifted to 70L, 70% germ. in the 4th w. Two other samples gave identical results. Seeds DS 1 y germ. 70L(80% in 1-7 w) and 70D(20% in 2-9 w), and seeds DS 2 y germ. 70L(6/7 in 5th w) and 70D(2/8 in 5th w) showing no significant dying or change in the light requirement.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Dietes p. 29. 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, 1998

Difficulty High Rated by us, not by the source.

Start around March 2, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 1, 2026.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

about 12 months from start to sowing. Then 35 days to germinate.

25% germination in 35 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Dietes p. 29Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora data is now more complete. Light is required for germination. Seeds germ. 70L(100% in 2-5 w), 70D(15%), 40-70D(7%), and 40-70L(40% in 2-4 w). When the sample in 70D was shifted to 70L, 70% germ. in the 4th w. Two other samples gave identical results. Seeds DS 1 y germ. 70L(80% in 1-7 w) and 70D(20% in 2-9 w), and seeds DS 2 y germ. 70L(6/7 in 5th w) and 70D(2/8 in 5th w) showing no significant dying or change in the light requirement.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Dietes p. 29. 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, 1998

Difficulty High Rated by us, not by the source.

Start around February 2, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on February 1, 2026.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

about 12 months from start to sowing. Then 63 days to germinate.

20% germination in 14–63 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Dietes p. 29Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora data is now more complete. Light is required for germination. Seeds germ. 70L(100% in 2-5 w), 70D(15%), 40-70D(7%), and 40-70L(40% in 2-4 w). When the sample in 70D was shifted to 70L, 70% germ. in the 4th w. Two other samples gave identical results. Seeds DS 1 y germ. 70L(80% in 1-7 w) and 70D(20% in 2-9 w), and seeds DS 2 y germ. 70L(6/7 in 5th w) and 70D(2/8 in 5th w) showing no significant dying or change in the light requirement.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Dietes p. 29. 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 6

DerivedN. C. Deno, 1998

Difficulty 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.

15% germination.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Dietes p. 29Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora data is now more complete. Light is required for germination. Seeds germ. 70L(100% in 2-5 w), 70D(15%), 40-70D(7%), and 40-70L(40% in 2-4 w). When the sample in 70D was shifted to 70L, 70% germ. in the 4th w. Two other samples gave identical results. Seeds DS 1 y germ. 70L(80% in 1-7 w) and 70D(20% in 2-9 w), and seeds DS 2 y germ. 70L(6/7 in 5th w) and 70D(2/8 in 5th w) showing no significant dying or change in the light requirement.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Dietes p. 29. 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 7

DerivedN. C. Deno, 1998

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

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

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

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

about 3 months from start to step 2. Germination happens during step 2; time not stated, 21 days assumed.

7% germination.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Dietes p. 29Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora data is now more complete. Light is required for germination. Seeds germ. 70L(100% in 2-5 w), 70D(15%), 40-70D(7%), and 40-70L(40% in 2-4 w). When the sample in 70D was shifted to 70L, 70% germ. in the 4th w. Two other samples gave identical results. Seeds DS 1 y germ. 70L(80% in 1-7 w) and 70D(20% in 2-9 w), and seeds DS 2 y germ. 70L(6/7 in 5th w) and 70D(2/8 in 5th w) showing no significant dying or change in the light requirement.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Dietes p. 29. 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 8

DerivedN. C. Deno, 1996

Difficulty Low Rated by us, not by the source.

Start around March 1, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 35 days to germinate.

100% germination in 14–35 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Dietes p. 39Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora germ. 70L(100% in 2-5 w) and none in 70D and 40.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Dietes p. 39. 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 9

DerivedN. C. Deno, 1996

  1. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing.

0% germination.

Nothing germinated at 70.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Dietes p. 39Public domain
Show the original text
Dietes (Iridaceae). D. grandiflora germ. 70L(100% in 2-5 w) and none in 70D and 40.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Dietes p. 39. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list.

How each step is done, in Deno’s words, and what Verified and Derived mean.

Germination trials

Readers’ own records of sowing this species, published after review. Share your trial · All trials

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