Success With Unrooted Zonal Geraniums

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Success With Unrooted Zonal Geraniums

To be successful with unrooted Zonal Geranium cuttings you must be properly equipped to handle them.  Bottom heat, automatic misting systems, sterile benches, sterile pots and soil are required for successful geranium propagation.

The following tips will help you succeed with your rooting program.

Pre-Planting Preparations:

  • Sterilize benches, and tools. It is not recommended to reuse pots or soil for geranium production.
  • Wash greenhouse down with a high pressure nozzle using soap and water.
  • Spray weeds in greenhouse with an appropriate herbicide.
  • Soil (media) considerations: light, well-drained media, 1:1:1 peat:perlite: soil; pH adjusted to 6.0.

WHEN CUTTINGS ARRIVE, OPEN BOXES IMMEDIATELY AND PLACE CUTTINGS IN COOLER (40°F) OR UNDER MIST. Prolonged time in boxes will increase exposure to ethylene gas and may result in leaf yellowing and delayed rooting.


  • Plant into pre-wetted soil, water-in and mist immediately, place under 1000-2000 foot candles of light.
  • Maintain root zone temperature at 68° F (20°C) for the first 16 days after planting. Monitor soil temperature closely with a soil probe.  Relying on air temperatures to gauge soil temperature is not accurate as mist will cool the media.
  • Rooting hormone will enhance uniformity in rooting.
    • Suggested product and application method: Potassium IBA (water soluble) @ 100 ppm applied as an overhead spray after the cuttings are stuck.  Apply within 24 hours after the cuttings are stuck and apply as a heavy spray to the point of run-off.
      • Apply in the morning when greenhouse temperatures are cool.  Cuttings must be nearly dry at the time of the application so choose a time when the mist can be turned off while minimizing stress to the cuttings.
      • Do not use a rooting hormone containing NAA which will cause the petioles to curl.
      • Do not use a hormone requiring dipping as the method of application to avoid the possible spread of disease.
  • Sample Misting Schedule For  Zonal Geraniums:
    • Day 1 – 3: Mist 24 hours per day, foliage should be constantly moist. Avoid stress. Apply only enough mist that there is a constant film of moisture on the foliage, avoid runoff.  Run-off will leach nutrients and slow rooting.
    • Days 4 – 6: Mist sun-up to sun-down. Foliage should barely dry before misting. Begin fertilizing with a balanced fertilizer complete with microelements on day 5 at 250 ppm N and continue fertilizing at that rate once weekly.
    • Day 7 – 9: Roots should be visible. Foliage should show a minimal amount of stress between mists.
    • Days 10 – 12: Mist as needed to reduce stress– approximately 45 min. to 1 hour on a sunny day. Soil temperature should remain at 68°F.
    • Days 13 – 15: Plants should be lightly rooted. You may turn off the mist.
    • Day 21: Continue to fertilize on a weekly basis.  Monitor EC and maintain below 1.0 mmhos/cm to avoid burning the roots.
    • Plants should be fully rooted and ready for transplant in 4 weeks.


*Misting schedules will vary depending on environmental conditions – this schedule is only a general guideline and misting schedules should be adjusting accordingly based on conditions in individual greenhouses.

*This misting cycle should not be used as a guideline for Regal or Ivy geraniums as the moisture needs in propagation for these crops will be much different than the needs of Zonal geraniums.

Disease & Insect Control:

  • Botrytis is the major disease concern in propagation.  Avoiding excess mist will minimize potential problems with botrytis. Periodic cleaning of yellow or infected leaves will also reduce risk. Providing good airflow will help prevent botrytis.  Weekly fungicide sprays are also recommended.
  • Rust prevention is also important as the propagation environment is favorable for the pathogen.   The following spray rotation is recommended:

Week 1: Strike +Daconil     – never use Strike more than one time every 4 weeks.

Week 2: Decree

Week 3: Heritage

Week 4: Sextant


*Remember, systemic plant bacterial, fungal, and viral diseases are not airborne. They must be transmitted by man, insects, or splashing water.

  • Do not interplant with crops that have not been tested for bacteria, fungi, and virus.
  • Wear clean clothes before handling geraniums.
  • Wash hands with soap and water before handling geraniums.
  • Incorporate a preventative spray program for insect control.
  • Do not handle tobacco products when working with geraniums. Be sure to scrub with soap and water after handling tobacco.

Sanitize everything that comes in contact with the Geraniums!!!!!!

Do not mix CVI® Geraniums with crops that have not been tested for bacteria, fungi and viruses.

Technical Support:

Log on to On Board at www. and go to the Geraniums Forum to post questions.  Your questions will be answered within 24 business hours.

Call or Email:

Rebecca Siemonsma

Technical Services Manager

Paul Ecke Ranch


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