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

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then 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.

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.
Jeffersonia seeds are hydrophilic and the embryo will die if seed dries out. Sowing the seeds before any drying occurs is the best approach. However, if they are to undergo a period of storage, they are first allowed to dry a bit and then are sealed in a plastic bag in slightly moist vermiculite. Expect germination while in cold cycle. 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.

*

This species needs special care as described.

D

Use repeated cycles of 20°C, then 4°C for 3 months each. Germination is very prolonged.
Hydrophilic, sow as soon as seed is ripe; If not sown right away after collecting the seeds need to be kept moist at all times to remain viable. For storage put in plastic bag with barely damp vermiculite; keep them warm during summer, coolish towards the fall and then 4⁰C at the onset of winter. Do not store them in the freezer because the formation of ice crystals will damage cell membranes
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

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then 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

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then 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.