Page 166 - Tài liệu cây cảnh Bonsai4me Bonsai Basics

that seeds that are released in late Summer and Autumn, go dormant for the

period of the Winter and then germinate when the soil temperatures rise in the
Spring. This dormancy means that seeds don't germinate immediately in Autumn
as they fall from the tree; this would result in young seedlings that would be
killed by the first frosts of winter. By germinating in Spring, a young seedling
has an entire season to grow and strengthen in preparation for its first winter as a
young sapling.
This is a good example of why it is important to understand the need to try to
imitate the natural growing conditions of an individual species to prompt it to
germinate. The easiest species to germinate are nearly always those that are
found locally; by virtue of the fact that these species are able to reproduce by
seed also means that your local climate is favourable for germinating its seed. If
a tree is able to germinate its seeds by simply dropping them onto the ground, so
can you.
Unless described otherwise in the Species Guides, seed can be sown in
Autumn straight into a prepared seed bed or a pot outside, the effect of repeated
freezing and thawing through the winter, followed by the gentle warming of the

soil and increased light in Spring will break the seeds dormancy and it should
germinate. This process of breaking dormancy is known as stratification.
Stratification
Stratification can be artificially created with the help of a refrigerator. This
can be necessary when trying to germinate seeds out of season, seeds that have
been stored inside over winter or seeds of species that will not germinate
naturally in your local climate.
Seed should be soaked in water for around 5 or 6 hours and then placed in a

damp plastic bag at room temperature for 3 or 4 days. Seeds that are seen to soak
when soaking in water are still viable for germination; any floating seeds are
empty shells and will not germinate, these should be removed. Care should be
taken with very small seed as they can all end up floating as a result of surface
tension!
The plastic bag of seed is then placed in the bottom of a refrigerator where
the temperature is around 4°C. The bag is then slowly moved up the shelves in
the refrigerator over a period of two weeks until it is placed on the top shelf
where the temperature is just above freezing. Over a second two-week period the
bag of seed is then slowly moved back down to the bottom of the refrigerator.
The seeds can then be removed from the refrigerator and sown.
Sowing Seed, Soil Mixes and Germination Temperatures

Seed that has been artificially stratified or seed that is being sown outside in