Floriculture Environmental and Modeling Research Progress Report — March 1992
Date 2/28/92
Title of Project Floriculture Environmental and Modeling Research at Michigan State University
Institution where work is being conducted Michigan State University
Amount of Endowment Grant $ 20, 000
Covering Period 1/92 to 12/92
Anticipated Date of Project Completion/Final Report 12/93 (6/94)
Individual(s) Conducting Project:
(List Project Leader First)
Dr. John A. Biernbaum - Title Associate Professor
Telephone Number 517/353-7728
Dr. Royal D. Heins - Title Professor
Mark V. Yelanich - Title Graduate Assistant
Floriculture Environmental and Modeling Research at Michigan State University
John A. Biernbaum, Royal D. Heins, and Mark V. Yelanich
Michigan State University
- A. Project Objectives:
- 1. Develop fertilization and irrigation strategies to minimize use and runoff of water and fertilizers.
- 2. Investigate root media nutrient analysis methods and interpretation guidelines.
- 3. Identify root media properties to maximize water and fertilizer efficiency.
- B. Summary of Work Conducted:
- With recirculated solution subirrigation methods of potted plants, water and fertilizer use can be
dramatically reduced compared to topwatering with no loss in plant quality. With traditional watering methods
as much as 40% or more of water and fertilizer is wasted in some instances. Recirculation of water does not
lead to plant death from the rapid transfer of Pythium from inoculated to non-inoculated plants although some
transfer can occur. The relationship between leaching and fertilizer concentration determines media nutrient
levels. The amount applied and wasted varies over 10 fold with different techniques. Water quality has
significant effects on root media pH, foliar residue and rooting of poinsettia cuttings. High pH and soluble salts
from alkaline water decreases rooting compared to rain water or reverse osmosis treated water. Fertilization
rates well below those currently recommended can be used to produce poinsettia stock plants of the same or
better quality than those grown with fertilizer rates recommended by fertilizer companies. The number of
irrigations required to maintain impatiens hanging baskets in an outdoor area can vary by a factor of two
depending on the water holding capacity of the root media. Stopping evaporation of water from the root media
surface significantly reduces water and fertilizer use by 20 to 40% during production of Easter lily and
poinsettias. The vertical movement of nutrients to the surface layer of the root media with subirrigation and
topwatering which decreases nutrient availability and increases fertilizer requirements can be reduced or stopped
with an evaporation barrier. Post production water loss in a simulated consumer environment can be reduced
by as much as 50% for poinsettia and Easter lily with pot covers to reduce water evaporation from the media.
Fertilization rates necessary for production and long term garden performance of flowering plants in ten inch
hanging baskets have been determined. Ten commercial root media and baskets from ten producers varied little
in their performance and water holding ability. Fertilizer requirements from June 1 to October 1 were met with
resin coated fertilizer so no additional water soluble fertilizer was needed.
and will be compared with results of similar studies at other universities. Poinsettias were grown in unamended
loose rockwool in six inch pots with only a complete nutrient solution containing 100 ppm nitrogen applied at
each irrigation (approximately once per week). Evaluation of flat electrode meters for pH, EC, nitrate and
potassium levels in fertilizer solutions and root media samples has been in progress since January 1. Modeling
of nutrient levels in peat based media used for production of plants in containers has started. Six important
flowering pot plant crops are being grown in a commercial peat based media or unamended loose rockwool in
pots with only a 100 ppm nitrogen solution from a complete fertilizer added at each irrigation.
recommendations will continue. Production of an educational video for training greenhouse operators and
employees to efficiently do on site soil testing is planned by the end of the year. Modeling of nutrient levels
and movements in media of container grown plants is in progress and will continue. Root media chemical
properties and evaporation of water from media will be investigated.
to irrigate and fertilize greenhouse crops with minimal water and fertilizer runoff. This research is developing
specific information needed for the transition to methods that are environmentally and economically sound.
Floriculture Environmental and Modeling Research at Michigan State University
Royal D. Heins, John A. Biernbaum, and Mark V. Yelanich
Michigan State University
- A. Project Objectives:
- 1. Investigate the control of stem elongation by day and night temperature.
- 2. Model the growth and development of poinsettia.
- 3. Model the growth and development of the Easter lily.
- 4. Model the growth of other floricultural plants.
- 5. Develop grower management tools from the above research.
- 6. Develop information necessary for the storage of seedlings and flowering plants.
- B. Summary of Work Conducted:
- Research in this project has resulted in the following information and concepts. Stem elongation, flower initiation, and
rate of plant development are all influenced by temperature. Stem elongation increases as the difference (DIF) between
day and night temperature increases. In contrast to stem elongation, flower initiation in most plants is influenced by
temperature during either part or the entire day. Non-optimal temperatures during the night (e.g. the poinsettia), the
day (e.g. the fuchsia), or both the day and night (e.g. the chrysanthemum) delay or inhibit flower initiation. Rate of
plant development is controlled by instantaneous temperature. Total time to unfold a leaf or develop a flower is the
summation of instantaneous rates of development. Models relating plant or flower development rate to temperature can
accurately predict accumulated plant development using hourly temperature averages or daily average temperatures when
temperatures are not excessively low or high. Comparing actual or predicted development with required development
over time can be used as a tool for precise timing and production of plants using a grower management tool called
graphical tracking.
based leaf unfolding model:
leaf over a three week period after pinching under varying greenhouse conditions.
following temperature based model.
stored without continued plant development in coolers under low temperatures for up to 6 weeks without plant
loss and subsequent delay in plant development and flowering after transplanting.
expert system program to develop an expert system to assist growers in making height control management
decisions (DIF and growth retardants). This computer program will be tested in nine commercial greenhouses
representing over one million poinsettia plants this fall.
after flower induction is complete to avoid vegetative pad formation. This means plants should not be leveled
until they have received at least five short days.
phenology model, based on inflorescence stalk stage, was developed and allows prediction of time to flower at
a particular temperature or required temperature for flowering to occur on a particular date.
greenhouses during the 1991 poinsettia season. Research on storage of bedding plant plugs is currently in progress on
assylum, vinca, tuberous begonia, New Guinea Impatiens, and tomato.
number, etc.) at the correct time. Delivery of plants with the right characteristics at the right time with minimal
chemical input is profitable to both growers and retailers. This research is designed to assist growers reliably produce
product at the right time within buyer specifications by developing models into grower management tools.
