Plant Propagation
Plant Propagation
• The process of increasing the numbers of a species,
maintaining a species, or preserving the vigor of a
plant.
Successful Plant Propagation
• Knowledge of technical skills
– The art of plant propagation
• Knowledge of plant biology
– Morphology, anatomy, physiology, etc.
• Knowledge of plants
– Selected method related to conditions and
techniques to propagate an individual plant
Plant Propagation
• Sexual Propagation
– Recombination of genetic materials to form
uniquely genetic individual
• Asexual Propagation
– Use of vegetative organs to create plantlets
genetically identical to parent plant
Sexual Propagation
Propagation by Seed
• Biology
– Pollination
– Anatomy
– Germination
• Applied
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Purchasing
Starting
Transplanting
Collecting
Storing
Pollination
• Pollination: transfer of pollen from anther
(male part) to stigma (female part) in a flower.
– Exchange of genetic material
Monocots vs. Dicots
Pollination
• Self pollination:
– Transfer on same flower
– From different flowers on the same plant o
– From flowers on different plants of the same
cultivar
– Examples: Beans, peas, lettuce, eggplant, peppers,
and tomatoes
Pollination
• Cross pollination:
– Transfer of pollen on plants of different cultivars of
the same species
– Examples: Onions, cucumbers, corn, pumpkins,
squash, broccoli, beets, carrots, cabbage,
cauliflower, melons, radishes, spinach, Swiss chard
and turnips
Pollination
• Fertilization
– the union of a male reproductive cell and a female
reproductive cell that is capable of developing into
an new individual
Anatomy
• Embryo: miniature plant in arrested
development
• Endosperm (Cotyledons): built-in food storage
• Seed Coat: hard out covering for protection,
prevents water from entering and initiating
germination before proper time.
Anatomy
Seed Coat
Endosperm
Embryo
Germination
• The process of seed growth and development
Germination
• Dormancy
– Viable seed that will not germinate when in
proper environment
– Due to internal or external cause
Germination
• Quiescent
– Ripened seed, ready to germinate, waiting for the
proper environmental conditions for germinations
– Allows seed to survive over periods of time
Germination
• Scarification
– Physically altering the seed coat to allow moisture
penetration
– Natural scarification processes: passing seed
through GI tract of animals, weathering of coat
– Artificial scarification processes: hot water bath,
sandpaper, etc.
– Breaks seed coat allowing moisture to enter!
Germination
• Stratification
– Exposing a seed to moisture and specific
temperatures (cold) in order to encourage
germination
– Degrades chemical inhibitors causing dormancy
Germination
• Factors affecting germination
– Water (moisture)
– Light (or dark)
– Oxygen
– Heat
Germination
• Water (moisture)
– Penetrates seed coat---Imbibition
– Endosperm swells- seed coat splits
– Dissolves nutrients to initiate germination
Germination
• Light (or dark)
– Can stimulate or inhibit germination
– Check seed package for planting instructions
Germination
• Oxygen
– Required for respiration
– Facilitated with light, well aerated soil mix
Germination
• Heat
– Optimum range for germination
– Many seeds have wide range
– Check catalog or seed package for instructions
– Drives metabolic process
Propagation by Seed
• Biology
– Pollination
– Anatomy
– Germination
• Applied
–
–
–
–
–
Purchasing
Starting
Transplanting
Collecting
Storing
Purchasing Seed
• Choose superior
cultivars
• High quality seed
– Disease resistant
cultivars when available
• Garden centers
• Mail order
– Obtain by mid-February
Purchasing Seed
• Germination rates
– Expected percentage of seed to germinate
– Generally, 65-80% will germinate
– 60-75% will grow into useful seedlings
– May affect density of planting
Starting
• Indoors
– Small seeds
– Long season plants
• Supplies needed
– Grow lights
– Clean containers (with drainage)
– Sterile seed starting medium
– Location with proper ventilation and temperature
Starting
• Growing media
– Loose, uniform, fine texture
– Mixes labeled for seed starting
– Pasteurized (sterile)
– May be low in fertility
Starting
• Containers
– Any container will do
– Disinfested
– Good drainage
– Adequate root space
Starting
• Containers
– Compressed peat pellets
– Peat pots
– Paper pots
– Plastic cell packs
– Flats
Starting
• Sowing
– Account for seed germination in timing factor and
growing time
– 2 weeks to germinate, 6 weeks to transplant date 8 weeks for full development time.
– Sow in mid-March or April depending on plant
species and growing conditions
Starting
• Fill container to within ¼ inch of the top of the
rim with moistened seed-starting medium
Starting
• Large seeds directly in pots or cell packs
– Squash, cucumber, watermelon – 2 per pot
– Use pencil or dibble to make hole for seeds
– Cover with media related to seed size
Starting
• Small seeds scatter on surface of large cell
packs or other containers for later transplant
– Sprinkle more potting media over seeds or
sphagnum moss (sphagnum moss helps prevent
damping off)
– Mix small seeds with sugar or extremely fine sand
to help with equal distribution
Starting
• Watering
– Water from below in tray before seeds germinate
and when seedlings are very small
– Allow drying between waterings
• Helps prevent damping-off
– Standing water in flats leads to disease problems
– Don’t allow seedlings to wilt
– Cell damage can occur that is permanent
Starting
• Moisture
– Plastic covers are useful to trap moisture
– Retains moisture
– Remove to promote hardening of tissues
Starting
• Supplemental lighting
– 3” – 4” from light source
– Cool white and warm white fluorescent lights
– Move lights as plants grow or move plants
– 14 – 16 hours a day
• Timers are inexpensive and very useful
– High intensity and quality light less leggy plants
Starting
• Temperature
– Nights 60 –68 F and 75 F
• Good rule of thumb-day temperatures 10 degrees
warm than night.
– Cool season crops cooler day/night temps
• 55 degrees night – 65 degrees day
– Warm season crops higher day/night temps
• 65 degrees night – 75 degrees day
– Heating mats
Starting
• Fertilization
– After germination
– Go ½ rate, avoid burn
– Two week intervals
Starting
• Transplanting
– Move to larger container when first set of true
leaves form
– Lift seedlings from containers with small flat tool
– Tease apart tangled plants/roots
– Handle by true leaves