Transcript FORCING BULBS

FORCING BULBS
copyright 2008 ©
By Donald L. Josko
605-361-4378
[email protected]
1
Bulb Basics
• Bulbs are modified stems.
• Bulb development is stimulated by:
– Temperature manipulation
– Light
– Moisture
• Quality Bulbs have all of the stored up food
necessary to develop into a root, shoot, and
flower.
2
Bulb Morphology
•
•
•
•
Bulbs have 6 parts:
Tunic-Outside papery scale.
Scales-Cortex tissue with stored energy.
Shoot-Organ that contains embryonic stems
and floral bud.
• Basal Plate Region-meristematic tissues that
generate the root plate or apical plate when
stimulated by proper temperature.
– Root Plate-region of the basal plate that
produce roots.
– Apical Plate-region of basal plate that produce
leaves, flower, and stem.
3
The Bulb Parts
4
Tunic
Root Plate
External Parts of a Bulb
5
Scale
G-Stage
Basal
Plate
Internal Parts of the Bulb
Root
Plate
6
Basal Plate Manipulation
• The basal plate is manipulated to change
into roots, shoots or flowers by:
– Exposure to Temperature
•
•
•
•
G-Stage 63 degrees Fahrenheit
Rooting 48 degrees Fahrenheit
Flower & Shoot Development 41 degrees Fahrenheit
Flower Maturation 36 degrees Fahrenheit
7
The Basal Plate Manipulated by
63 Degrees F
8
Checking for G-Stage
1) Using a sharp knife remove scales and
tunic.
2) With G-stage and apical plate remaining
to basal plate remove the top of G-stage.
3) If the inside is hollow G-stage has not
been reached. Retreat with 63 degree F
4) For 1 week and recheck another bulb.
9
G-Stage Achieved
The center is solid containing the
embryonic stem and flower parts.
10
G-Stage Not Achieved
Center is hollow, plant would only produce
leaves
Tunic
Scales
G-Stage
Not Achieved
11
•Once G-Stage has developed the bulbs are planted.
•Planted bulbs will be manipulated by staged decreases
in temperature.
•Each stage of temperature decrease is determined by visual
evaluation by the grower.
48F degrees will stimulate rooting.
This temperature will be maintained until
roots emerge from the bottom of the pot.
41F degrees will stimulate shoot elongation
This temperature will be maintained until
the shoot emerges 1 ½” above the bulb tip.
36 F degrees will stimulate flower development
This temperature is maintain for 1000 hrs.
60-70 F degrees will result in flowering.
You can influence the speed of development by reducing
temperature or placing the pot back in a dark cooler (36F)
to achieve a perfect bloom time of the crop.
12
The Basal Plate Manipulated
by 48 Degrees F
13
Roots Develop From Root Plate
14
The Basal Plate Manipulated
by 41 Degrees F
15
Shoot
Shoot Emerging From Apical Plate
16
The Apical Plate Manipulated
by 36 Degrees F
17
Typical Bulb Forcing Schedule
Plant bulbs the 1st week in October
*Water pots in with a fungicide(Banrot)
*Place in a cooler set at 48 degrees F
Hold 48 degree temps until you see roots in the holes in the
bottom of the pot. Approximately November 10
* Turn Temps down to 41 degrees F
Hold 41 degrees until shoot emerges to 1 ½”
* Turn Temps down to 36 degrees F
*Hold for 4 weeks
Force bulbs in the greenhouse at 60 degrees F
* Bulbs are ready to sell when buds emerge
*About 2nd week of Feb
Adjust schedule with 18-19 weeks to complete a crop.
18
Hints To Forcing Bulbs
1) Feed 100ppm of Calcium Nitrate when bulbs are placed
into the greenhouse from the cooler.
2) If your crop in the greenhouse is too far ahead place pots
back into cooler with no light.
3) Soil mix should be airy. High perlite or rice haul content.
4) Check moisture content or the pots in the cooler.
5) Have a soil thermometer in the pots in the cooler and the
greenhouse .
6) Use Bulb pans and plant in odd numbers.
19
Bulb Quality
• Avoid Light weight bulbs.
• Avoid Soft Bulbs
• Avoid bulbs that ooze & have foul odor
• Inspect 1 bulb per lot to check for g-stage
20