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– 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

Embryo

Endosperm

Seed Coat

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