Propagation Environment pt 2

• Automated watering is cheaper
• Droplet size is important
• Seedlings are sensitive to salts in water
• good quality water: EC = 0.75 mS/cm and sodium absorption ratio is 5
• Water with high sodium can negatively affect properties of media
• Hard water leaves scale and clogs mist nozzles
• pH of 5.5-7 is the best for most plants growth
• Watering options:

  • hand watering with rose-style nozzle
  • overhead sprinkler for nursery containers
  • sprinkler irrigation for greenhouse containers
  • automated irrigation triggered by a switch that turns on water as plants pass on an overhead conveyer belt
• Smart booms have controllers to schedule misting
• Microirrigation systems for container-grown plants can efficiently irrigate container plants with less water then overhead irrigation systems
• Subirrigation systems:

  • ebb and flood system
  • capillary mat system
• Ebb and flood system: bench is flooded with water/fertilizer for a predetermined time before water is drained into the retainer tank
• Capillary mat system: the floor or benchtop is covered with a water-retaining mat that is periodically wetted
• Fog systems work by maintaining high humidity in the greenhouse
• Fogging systems generate small water droplets that stay suspended in the air
• Fogging doesn't wet the leaves as much as misting
• Temperature is important for germination and root initiation
• seed stratification: seed dormancy is broken in some woody speciesby cool-moist stratification conditions that allow germination tooccur
• Heating mats can be used for seed germination and root initiation
• grafting heating devices are sometimes placed at the graftingunion area to speed up the healing process or union formation, whilethe rest of the rootstock is kept dormant
• For adventitious root formation, germination of seeds and plugdevelopment, oxygen must be available as high respiration rates occur
• Impervious seed coats reduce germination in seeds due to failure ofgases to penetrate into the seed
• During propagation in enclosed propagation structures eg.Greenhouses, ambient carbon dioxide levels can drop to belowoptimal levels thereby reducing the photosynthetic rates
• Ethylene gas (C2H4) can build up in the greenhouse, or in storage ofpropagules thereby resulting in deleterious conditions
• Phosphorus is used for good root establishment
• fertigation: the application of soluble fertilizer during the irrigation of a seedling or rooted cutting
• Structures used to germinate seeds or to root cuttings or tissue culture microplants:

  • greenhouse
  • modified quonset
  • hotbed
  • micropropagation lab
• Structures used as preparation to transplant outdoors:

  • cold frames
  • lath houses
  • low polyethylene tunnels
• gas fired infrared heaters: radiant heaters that heat plants rather than the air
• root zone heating: pipes are placed with recirculating hot water on or below the soil surface which hastens the germination of seeds
• solar heating: conserves daytime solar heat for night heating
• pad and fan system: reduces air temperature by raising the humidity and circulating the air, wet pad is installed and one side with large exhausts on the other
• Fog method of cooling can introduce pathogens
• thermal and shade curtains: reduce heat loss during the winter and heat stress during the summer
• Black mesh fabric is used to reduce light irradiance and heat load
• Aluminum thermal fabric is used to retain heat
• Red netting is used for enhanced root initiation
• cold frame: unheated sun tunnel
• hot frame/hot bed: heated sun tunnel
• lath house: shade house