This document discusses propagation of seeds both indoors and outdoors. It describes controlling the germination environment indoors through choices of growing medium, water, heating, and hygiene. Seeds can be sown in containers like trays or modules and may require pricking out. Outdoor sowing uses techniques like stale seed beds and thinning, with examples given of annuals and biennials sown directly in the ground. The learning outcomes cover describing conditions for germination, sowing and care of seeds indoors and outdoors.

1. RHS Level 2 Certificate Year 1
Week 13 – Propagation
by seed in practice

2. Learning outcomes
1.1 Describe how conditions for successful germination
can be achieved in a protected environment.
1.2 Describe the sowing and aftercare of a range of
seed types sown in containers.
1.3 Describe how the conditions for successful
germination can be achieved in the open.
1.4 Describe the sowing and aftercare of a range of
seed types sown outdoors.

3. Seed propagation in a protected
environment
 Control
of the environment means that the
germination conditions can be optimised
 Important factors in this control are the
choice of growing medium, water supply, use
of a propagator or heat pad, mist bench use
and cultural hygiene.

4. Practical steps to control germination
environment
Use of sterile, moisture retentive,
free draining seed compost
Allows oxygen to enter the soil
whilst holding water. Sterile
compost reduces the risk of
‘damping off’ diseases.
Supply of clean water – not rain
water
Reduces the risk of ‘damping off’
Use of heated propagator or heat
pad
To allow soil temperature to be
controlled
Light – use vermiculite or compost
to cover seeds unless they need
light to germinate.
To provide the light conditions
needed to germinate.
Cultural hygiene
A basic requirement of any
propagation

5. Equipment
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Containers – seed trays, modular trays, seed pans,
Jiffy 7’s, root trainers.
Propagator – may be a simple plastic cover for a
seed tray or a more sophisticated heated unit.
Conserves humidity and temperature.
Heat pad – thermostatically controlled and placed
under the seed tray.
Mist bench – commercial use, provides heating and
misting.

6. Sowing seeds in a modular tray
 Used
for those plants which resent root
disturbance and for larger seeds
 No need to prick out so less labour intensive
 Takes up more space for fewer plants
 Unlike seed trays they tend not to be reuseable.

7. Pricking out
 Required
for seeds that have been grown in
a seed tray.
 Moves the seedlings from the seed tray into
individual modules or pots to grow on.
 Requires a degree of care and skill.
 Must be done at the right stage of growth or
the seedlings will become crowded and
‘leggy’ and there is the risk of fungal disease.

8. Seed propagation outdoors
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Used for hardy annuals, hardy perennials and many
vegetables.
Cultivation – the aim is to produce a fine tilth
For ornamentals unlikely to need additional fertilizer
Use of the Stale Seed Bed technique to reduce
competition from weeds
Sow either broadcast or in drills – the latter makes it
easier to see which are weed seedlings.
Keep watered and weeded, thin out to final spacing,
provide support and dead head ornamentals as the
season progresses to prolong the display

9. Plant examples
 Hardy
annuals usually sown direct into the
ground – Papaver rhoeas ‘Shirley Series’,
Clarkia amoena, Centaurea cyanus
(Cornflower).
 Biennials often direct sown – Verbascum
olympicum, Digitalis purpurea, Myosotis
sylvatica.

10. Learning outcomes
1.1 Describe how conditions for successful
germination can be achieved in a protected
environment.
1.2 Describe the sowing and aftercare of a range of
seed types sown in containers.
1.3 Describe how the conditions for successful
germination can be achieved in the open.
1.4 Describe the sowing and aftercare of a range of
seed types sown outdoors.