Fact
Sheets
Seed Sowing Basics
Seed of most perennials, trees, and shrubs may be sown in the late
Winter or early Spring, allowing exposure to cool and moist conditions
that trigger germination. Some species will require two winter seasons
to germinate so keep your seed pots even if nothing germinated the
first year. Try to mimic the plants natural seasonal cycles. For
alpine plants the seed falls in the summer when its dry, then gets
exposed to cool, then cold conditions. In the Spring the snow melts
and the seeds get lots of cold water and gradually warming temperatures.
We can re-create natural conditions by leaving the seeds outside
for the winter, or using the refrigerator. In general, seeds require
10 weeks of cool and moist conditions to germinate. This process
is called stratification.
Seed Starting Soil Mix
One recipe for seed sowing media is:
Fine Peat or coconut fiber: 1 part
Pumice: 1 part
Sand: 1 part
You can try many combinations of mixes. Commercially available
mixes are also good…the compositions will vary.
Containers
Many different types of containers are appropriate to germinate
seeds. Simple plastic 4" pots are readily available: chances
are you have some left over from the nursery and last years plant
shopping. Wash them in hot soapy water before using them again.
Clay pots work well too but dry out faster. If you have a large
quantity of seeds to sow consider a flat…fill 2/3 with media
and evenly scatter the seed. Sowing seed too close will result in
difficulty transplanting them later.
Label your pots with the plant name, source, and date sown to keep
track of when you planted them.
Light
Some seeds require light to germinate, and others need to be covered.
Generally, tiny seeds are left uncovered, and larger ones are covered
with soil media to a depth equal to the diameter of the seed.
Water
Water your seed pots before sowing, and mist gently after. Avoid
splashing water into the pots as this will splash out your seeds.
Water from the bottom by standing pots in an inch of water or mist
from the top. Don't allow the pots to sit in water for more than
20 minutes or dry out.
Temperature
Some seeds need cool temperatures to germinate, including alpines
while others require warmer conditions. If you use the refrigerator
for a cold moist period (stratification), place pots inside a sealed
plastic bag to help retain moisture. Check seeds weekly to ensure
they don't dry out or develop mold. After 10 weeks, remove opts
from the refrigerator and lace in a cool bright location. Most perennials
can be germinated indoors in a sunny windowsill. Alpines and shrubs
are best sown outdoors.
Germination
The first part of a plant to appear is the radical or root. Once
anchored, the cotyledons, or seedling leaves appear. They are often
very simple and bare little resemblance tot he mature leaves.
Transplanting
After the second set of leaves appears you may transplant the seedlings
to individual pots. If they are still too small to handle let them
grow a little more until you are comfortable working with them.
Slide the plants and soil out of the pot and gently tease apart
the roots, holding the plants by their leaves. Place in the new
pot and gently tap the soil down.
Fertilizing
Feed seedlings with half strength plant food of your choice. If
the seedlings stop growing or turn yellow feed them. Often this
happens because the seed starting mix has little fertilizer in it
and it runs out before you transplant them.
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