Germination Guide

Click on a species name below to see it's germination tips.
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Jasione amethystina

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione crispa

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione crispa ssp. amethystina

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione dentata

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione heldreichii

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione humilis

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione jankae

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione laevis

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione montana

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione perennis

A

Sow @ 20°C. Seed germinates within 3 months.
Jasione sp.

L

Expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

Jeffersonia diphylla

!

Sow immediately. The viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience.

*

This species needs special care as described.

H

Use repeated cycles of 4°C, then 20°C for 3 months each. Germination is very prolonged.
germination unlikely after dry storage > 6 months; leaf may not emerge for 2 cycles after radicle. Research by Jeffery and Carol Baskin demonstrated "Freshly-matured seeds of ... Jeffersonia diphylla .....have underdeveloped (ca. 0.6 mm in length) embryos and exhibit deep, simple morphophysiological dormancy (MPD). For rapid growth of the embryos at October (20°/10° C) and November (15°/6° C) temperatures in October and November, seeds must first be exposed to high (30°/15°C) summer temperatures. If embryo growth is not completed in autumn, it continues during winter. However, even after 10-12 weeks at summer temperatures, embryos grew very little at 5°C, unless growth already had begun at autumn temperatures. After embryo growth has been completed, or after it has been initiated, seeds require cold stratification (5°C) to overcome dormancy. Embryos must attain a minimum length of about 1 mm before seed dormancy can be broken by cold stratification. Gibberellic acid increased the rate of embryo growth in seeds kept at 20°C, but only 1-9% of them germinated. Thus, GA substitutes for warm but not cold stratification. High summer temperatures, as well as the traditionally-used autumn and winter temperatures, should be used in germinating seeds with deep, simple MPD."
Jeffersonia dubia

!

Sow immediately. The viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience.

D

Use repeated cycles of 20°C, then 4°C for 3 months each. Germination is very prolonged.

*

This species needs special care as described.
germination unlikely after dry storage > 6 months; keep seedings in original pot for 1-2 years before separating
Jovellana sinclairii

A

Sow @ 20°C. Seed germinates within 3 months.
Jovibarba heuffelii

A

Sow @ 20°C. Seed germinates within 3 months.
Juglans cinerea

*

This species needs special care as described.

N

Sow directly in garden.
protect seed from squirrels by covering with metal mesh
Juncus effusus

A

Sow @ 20°C. Seed germinates within 3 months.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...
Junellia micrantha

2

Requires darkness.

L

Expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

Junellia wilczekii

2

Requires darkness.

L

Expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

Juniperus horizontalis

H

Use repeated cycles of 4°C, then 20°C for 3 months each. Germination is very prolonged.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
soak seeds a few seconds in boiling water
Juno bucharica

*

This species needs special care as described.

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Juno caucasica

*

This species needs special care as described.

A

Sow @ 20°C. Seed germinates within 3 months.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Jurinea cadmea

A

Sow @ 20°C. Seed germinates within 3 months.
Jurinea consanguinea

A

Sow @ 20°C. Seed germinates within 3 months.
Jurinea mollis

F

Sow @ 4°C.
Jurinella moschus

A

Sow @ 20°C. Seed germinates within 3 months.
Jurinella moschus ssp. moschus

A

Sow @ 20°C. Seed germinates within 3 months.
Jurinella moschus ssp. pinnatisecta

A

Sow @ 20°C. Seed germinates within 3 months.