Cultural Practices Curriculum Content

Special Materials and Equipment:

Numerous houseplants, flats, media, clear domes, mum cuttings, and 6 inch pots.

Evaluation:

Written test, quiz, work sheet, and/or application exam.

Interest Approaches:

1. Have a wholesale grower come in and speak to the class.

2. Go on a field trip to a local greenhouse to see production at work.

3. Display flowering plants around the room.

4. Display seeds and different forms of vegetative propagation on students' desks (i.e. a leaf, a tip cutting, a stem cutting, etc.). Ask the student which plant parts will form a new plant.

5. Have examples of plants that have been pinched, disbudded or repotted incorrectly along with correctly. Ask the students what they think went wrong. Have them write it down. At the end of the unit, have the students do it again and compare their before and after answers.

CONTENT/LEARNING ACTIVITIES: CULTURAL PRACTICES (2171)

I. Propagation Plants See websites:

A. Terms associated with Plant Propagation

1. Asexual Propagation - A method of reproducing a plant by vegetative tissue, creating new plants.

2. Sexual Propagation - Allowing a plant to produce a seed, and then allowing the seed to produce a new plant.

3. Callus - Cells that form near a wound on a cutting. They have no differences of operation or task.

4. Cotyledon - The first leaf to emerge during germination.

5. Cutting - A piece of vegetative plant tissue that when treated properly will regenerate a new plant.

6. Division - A method of propagation where a mature stock of parent plant is separated, cut or divided into smaller sections, allowing each division or section to become a larger plant.

7. Leaf Cutting - A leaf blade and peptide or a leaf blade is used to propagate new plants.

8. Leaf Bud Cutting - Taking a section of stem that has a leaf bud and axillary bud to produce a new plant.

9. Micro cutting - Tiny stem tip cuttings that are produced through tissue culture techniques. These plants must be rooted before going into a greenhouse.

10. Mist Nozzle - Irrigation head that produces a fine mist that gently waters propagation tables containing new plants.

11. Plant Propagation - Making more plants from parent plants or "stock plants".

12. Propagation Bench - A table or surface on which plant pots, or trays (flats) may be placed in order to receive water and heat in addition to light.

13. Separation - Removing newly formed plants from the parent plant.

14. Stem Tip Cutting - A section of the stem which includes the growing tip and several side or lateral buds.

15. True Leaves - The first and all others that form after the cotyledons have emerged.

B. Propagation Benches

1. Propagation benches are used to root plant cuttings or germinate seeds of plants. Most provide water and sometimes additional heat which is necessary for some plants to successfully be propagated. Sometimes it is just to quicken the process.

2. There are different kinds of propagation benches to be used. Mist tables are the most common for high schools.

a. Mist tables provide high humidity to reduce transportation.

b. The benches should be easy to clean and sterilize.

c. Excess moisture should quickly drain from the bench to reduce the chances of disease problems.

3. Heating propagation benches above the greenhouse air temperature will help produce roots faster. This can be done in 3 different methods.

a. Propagation Mats - These are rubber mats approximately 22" x 60" in size that have wires within them for heating small areas. The mats are waterproof, and have an external thermostat that can be set for the desired temperature and plugged into any electrical outlet. They work well in small areas, but are too expensive for a large area.

b. Root Zone Heating - Tubes are placed in the bench, under the bench, or on the floor and hot water is run through them. This method is very economical and very useful in heating large areas. The containers are placed on the tubes and the media is heated, increasing root development and reducing the amount of time for root development by 20 to 40 percent.

c. Under bench forced air - Hot air is forced or blown under the benches from a tube with holes in it or a "Jet Pipe". This form of heating the bench poses the problem of drying the plants and media and evaporating the mist too quickly. Compensation by increasing mistings or misting time may be necessary.

C. Propagation Containers

1. Seeds

a. Generally, seeds are started in flats These are trays of 11" x 22", and are sown by hand. Sometimes these are called community trays. Occasionally small amounts of seeds are to be started. These can be started in 6" pots or undivided cell paks.

b. If using automation for large crops, seed trays called plug trays are used. They may contain anywhere from 162 to 580 plugs (or cells) per tray.

c. Large seeds are easily handled and may be sown directly into the container to be grown in or into cell paks. This cuts production costs because of the reduced labor in transplanting seedlings to the final container.

2. Cuttings

a. Flowering plants can be propagated directly in growing containers, but may be grown in media. Such as oasis, perlite or vermiculite, or rockwool. If grown in the synthetic media, transplanting will need to be done.

b. Foliage plants tend to do better in flats or trays. Sometimes Jiffy Pellets or small pots can be used. If they are grown in their containers, many of the varieties of foliage plants will require a longer period of time to produce roots and establish themselves.

D. Germination Media & Seed Growing Methods

1. Most growing media is too course to be used as a germination media. Fine particles are needed to keep moisture levels high, and yet allow enough oxygen to reach the seed to continue germination.

2. There are commercial mixes available for use that not only provide this texture and water holding quality, but also include a nutrient charge for faster root development.

3. Try not to skimp on the media for starting seeds. It may mean the difference between an okay crop and a fabulous crop.

4. The placement of the seed in the media is also important. Some seed requires darkness to germinate, others light. Be aware of this requirement.

5. Some seeds will require added heat or cooling in order to germinate.

E. Transplanting Seedlings

1. From flats

a. Carefully separate seedlings after they have developed two true leaves and are large enough to handle. Don't allow them to grow too large and end up a tangled mess of roots.

b. Water flat before moving seedlings out.

c. Fill containers for growing with media. Be sure it has been moistened.

d. Make a hole, or dibble holes for seedlings.

e. Loosen soil or media under the seedlings with a pencil or your finger.

f. Sort out of a small group of seedlings, those plants of uniform size and vigor.

g. Pick up the plants by the leaves only, and place them into the holes.

h. Only compress the media around the plants enough to hold them in place.

i. Water the seedlings immediately after transplanting.

2. Plugs

a. Plugs should have several leaves, and show signs of some root development in the plug tray.

b. Fill containers with media.

c. Water the plug before transplanting.

d. Loosen the plugs from the tray.

e. Dibble holes large enough to hold the plug in its entirety.

f. Fill soil around the plug.

g. Water and move to growing area.

F. Chemicals and Root Production

1. Rooting hormones are used to speed the development of adventitious roots on the base of a cutting.

a. IBA (Indolebutyric Acid) and NAA (Naphthaleneacetic Acid) are most common.

b. Some rooting hormones contain a fungicide to prevent fungal disease.

2. Powders

a. Apply powders to the ends of freshly cut stems. If they are dry and the powder doesn't stick, they can be wetted. Don't put the stems into the can or container of powder. It will contaminate all the powder. Put some into a dish or on a tray and dip the stems from that. Immediately stick the cuttings into media that you have pre-opened with a dibble stick or pencil so that the powder is not rubbed off during insertion.

b. Do not return unused powder to the container. Discard the hormone that was used properly.

3. Liquids

a. Place some of the liquid in a beaker or flask large enough to put stems into the liquid.

b. Immerse the freshly cut ends of the stems in the liquid for about 30 seconds.

c. Remove the cuttings and stick them.

d. Discard the contaminated liquid when finished.

e. Rooting hormones are economical and produce very positive results when used as directed.

G. Sticking Cuttings

1. The sticking of a cutting can produce or fail to produce a new plant by how it is done.

a. The media is to be moist.

b. Mist the cuttings while sticking to prevent wilting.

c. Remove any leaves that may be buried so it doesn't cause disease to spread.

d. Treat the cuttings with hormones.

e. Make sure holes are made large enough to get the stem in, and don't compress the soil around the stem.

f. If using a media that is synthetic only place the stem in far enough to hold it up.

g. Don't condiment the cuttings.

h. Hand water all cuttings.

i. Cuttings will need to be misted on their growing points to ensure success.

j. There should be a thin film of water on the foliage at all times.

H. Transplanting Rooted Cuttings

1. Reduce the amount of mist on the cuttings 7 to 10 days before you want to transplant. This will allow the transpiration system in the plant to start working; and get it easy to move into the climate of the production or growing area.

2. All plants should be watered immediately before being moved into the growing area. Plants in pots can continue to grow. Those in strips of oasis or rockwool will need to be transplanted into pots or production containers.

3. Fill the container with media, dibble the hole and place the transplant in. Firm the soil only enough to hold it in place. Make sure to bury the entire oasis or rockwool cube to prevent wicking of water away from the roots into the air.

4. Double water the plants after transplanting to remove air bubbles.

5. When all the transplants have been placed on benches, apply a fungicide drench to help prevent spreading disease.

6. On the next watering, start applying fertilizers to the media.

I. Micro Cuttings:

1. Micro Cuttings are produced all over the U.S. by using sterile tissue culture methods of reproduction. Some companies sell the new plants which they call micro cuttings to other growers all over the world.

2. The micro cuttings will be shipped without root systems and must be treated with rooting hormones to produce new roots.

3. Strict sanitary requirements must be followed with this procedure to protect the new plants from harmful bacteria and fungi.

4. After they have formed roots they are handled and grown like any other cutting.

II. Discuss pinching and disbudding plants.

A. Some plants require special cultural practices during production to produce visually attractive plants.

B. Pinching - Removing the growing point of a shoot eliminates the natural occurring hormones; when the hormones are absent the axillary buds break and develop.

1. A well branched plant that appears full is produced after the pinch.

2. Pinching should be done while the stem tissue is soft and immature. 3. Remove approximately the terminal 1/4" - ½" of the shoot when pinching. If the pinch is done late, and the tissue has already gotten woody, new branches will be slow to develop.

4. Pinching can be used to even up the height of a container that has several cuttings of various heights.

C. Disbudding - Removes certain immature flower buds to improve the overall floral display of that shoot. Mums and carnations are two crops that must be disbudded.

1. By removing a portion of the flower buds from the shoot, the remaining buds develop into larger sized flowers and a more attractive display results.

2. Buds should be removed as soon as they are large enough to be handled.

3. Roll the small bud and peduncle downward with your thumbs while supporting the shoot tip with your remaining fingers. They should easily roll out of the leaf axil and the peduncle should snap off with the bud.

4. If disbudding is done too late, the peduncle will be difficult to remove and a visible wound will remain. The remaining flower buds may not fully expand.

5. There are three types of disbudding that can be done.

D. Center bud removal (CBR) - Removes only the terminal flower bud from each shoot. This type of disbudding is used when spray type cut mums (many flowers on a single stem) or certain cultivars of pot mums are grown.

E. Lateral bud removal (LBR) - Often called regular disbudding. This type of disbudding removes all lateral buds except the terminal bud on each shoot. This type of disbudding is used in carnation production, standard cut mum (one large flower per stem) production, and on certain cultivars of pot mums.

F. Multiple bud removal (MAR) - A very soft pinch is made on each shoot after the buds have formed. This type of disbudding removes the terminal bud and a few of the apical lateral buds. It is recommended for certain cultivars that do not space their floral.

III. Planning production schedules

A. The scheduling of a crop is essential so the greenhouse staff will know when and how much bench space will be needed. In addition, planning and scheduling must be done to guarantee that a crop will be ready for sale at the proper time.

B. Target sales dates should be decided upon first. All crop scheduling involves working backwards from the sales or finished date of the crop.

C. Crop variability plays a major factor in determining the production schedule. Some crops can be started a few weeks before the sales date and others may require four months. A grower must be familiar with the requirements of each crop.

1. Plant and seed suppliers are good sources of scheduling information. Seed catalogs and trade magazines also offer helpful schedules on crop production. Make sure you are informed about the crop you plan on growing.

2. Scheduling a crop is a trial and error process the first few times a species is grown. After that the grower is familiar with the growth characteristics of the plant, and there are production records to use so the schedules can be fine tuned.

D. General schedule calculations for five types of crops are given below. Remember, these are only guidelines and should be used as tools when determining your own schedule.

E. Bedding plants

1. For bedding plant crops that are propagated by cuttings the schedule will depend on whether rooted cuttings are being purchased, or if the greenhouse is going to root their own cuttings.

2. Rooting of cuttings generally takes 14-21 days. Determine how long rooting takes for your crop.

3. Pinching may or may not be needed on your crop. If pinching is done the plant will require an additional 7-14 days to flower; however, the pinched plant will be fuller, more attractive and usually bring a higher price.

4. The time of the year will also have an effect on how fast the crop is produced. Cuttings started in January will take longer to produce than cuttings started in March; the brighter days and warmer nights speed up the process.

5. This is a typical schedule for cutting produced geraniums using both rooted and non-rooted cuttings.

Rooted Non-rooted

Cuttings Cuttings

Sale date 5-1 5-1

Retardant 3-30 3-30

(if needed)

Pot cuttings 3-13 3-13

Stick cuttings -- 2-27

6. The rooted cuttings that were purchased required 2 weeks less greenhouse time and labor; 7 weeks total compared to 9 weeks total if the greenhouse rooted the cuttings.

F. Bulb crops - Can be forced into bloom in pots and sold in the early spring. There are certain cultivars of tulips, daffodils and hyacinths that have been bred for pot forcing.

NOTE: The Holland Bulb Forcer's Guide is a good reference book on forcing potted bulbs. This is a manual that gives detailed instructions on how to force these crops; it even has specific information for each cultivar.

1. All bulb crops require potting in the fall and then they must be chilled for a period of time. The grower must have access to a climate controlled cooler where the bulbs can be stored in the dark for several months.

2. This vernalization treatment is what caused the flower stalks to elongate and blooms to emerge when the pots are put in a warm greenhouse.

3. Most cultivars require 15 weeks of 40°F-45°F temperatures; however, this can vary from 12 weeks to 21 weeks depending on the cultivar.

4. When bulbs are potted the tip of the bulb should stick out of the media. They should be thoroughly watered, drenched with fungicide, and placed in a dark cooler. Check the pots at least once a week while in the cooler, and water as needed.

5. Tulips are potted 3 bulbs per 4" pot and 6 bulbs per 6" pot, hyacinths use 1 bulb per 4" pot and 3 bulbs per 6" pot, daffodils are usually only forced in 6" pots using 3 bulbs; there are a few new cultivars being introduced for 4" forcing.

6. After the vernalization treatment is over, move the pots to the greenhouse and force them at a pot to pot spacing with an average night temperature of 63°F-60°F.

7. The length of time in the greenhouse to force the plants will depend on the species and the time of year; tulips and daffodils require 4-5 weeks in January but only 2 weeks in April.

8. Growth retardants may or may not be needed depending on the cultivar; they are applied as a soil drench.

9. Below is a typical schedule for tulips forced for Valentine's Day.

Sale date February 7, 1993

Apply growth retardants January 13, 1993

Pots in greenhouse January 10, 1993

Pot bulbs and place in cooler September 27, 1992

G. Foliage plants - Production today commonly involves the use of specialized foliage producers in Florida and California. Economically it is cheaper for a greenhouse to either buy cuttings or tissue cultured finished plants from these specialized growers rather than try to produce their own plants.

1. Foliage plants are reasonably priced since many of them are propagated by tissue culture techniques.

2. A greenhouse grower saves time and labor by not having to propagate and then finish the foliage plants. A 6" Dieffenbachia that is full can be purchased from a specialty grower for $3.50-4.00. It may take your greenhouse 9-10 months to produce a comparable plant.

3. Three months is considered average for the production of a quality 4-6" foliage plant depending on the species.

4. Foliage plants are easy to propagate and many techniques will work; air layering, division, stem tip cuttings Some species are quick to root and grow and other are very slow.

5. When propagating foliage make sure the night temperature is at least 68°F and the cuttings have enough shade. Very few foliage plants can withstand high light intensities.

6. Most foliage plants are rooted 14 days after sticking and can be transplanted at that time. They often require several pinches to produce full plants.

7. Below is a typical schedule for producing Pothos hanging baskets

Sale date August 1, 1992

Pinch July 4, 1992

Pinch June 6, 1992

Pinch May 2, 1992

Stick 10 single March 28, 1992

eye cuttings/basket

H. Blooming pot plants - Have been considered the bread and butter of the greenhouse industry These plants are ones that are grown on a year round basis - mums, African violets, gloxinias, or for holidays - Easter lilies, poinsettias, hydrangeas.

1. These crops generally have a specific sale period and the grower must make sure that the plants are ready on time; no one wants to buy an Easter lily the day after Easter.

2. Seasonal and blooming pot plants generally require more specialized treatments to force them to bloom at a specific time; Easter lilies must be vernalized, mums must have the day length altered.

3. These crops are slightly more difficult to schedule because they are usually pinched, treated with growth retardants and require special fertilizers. It is very important that good records be kept on these crops during production.

4. The information below covers a seasonal and blooming pot plant.

I. Poinsettias - are generally propagated in August and sold from Thanksgiving through Christmas.

1. A 6" or 6.5" pinched plant is the most commonly produced container.

2. Poinsettias require 8-10 weeks of short days to bloom depending on the cultivar.

3. When producing poinsettias be aware of these dates for Oklahoma production:

September 1 - last day to propagate; except for 4" pots

September 25 - plants established in final containers

October 1 - last day to pinch plants

October 10 - natural flower bud set occurs

October 25 - last day to apply growth retardant

4. Cuttings require 14-21 days to root.

5. Here is a typical production schedule for poinsettias:

Bloom November 26-December 3

Growth retardant applied October 17

Pinch September 26

Transplant September 5

Cutting stuck August 15

NOTE: A good reference book for producing poinsettias is the Ecke Poinsettia manual. This book is written by the Ecke poinsettia staff and covers all aspects of poinsettia production.

J. Chrysanthemums - are grown year round as blooming pot plants.

1. Mums are photo periodic; they produce vegetative tissue under long days and initiate and form flowers under short day conditions.

2. Mums are classified and sold according to their response group; the weeks of short days required to induce flowering. They are also grouped according to how vigorously they grow; short types are the least vigorous, medium types are intermediate in growth and tall types are the most vigorous.

3. Specialized propagators sell rooted and un-rooted mum cuttings to greenhouse growers who produce the potted plants. Very few growers maintain their own stock plants. Cuttings purchased from specialized growers are healthy, vigorous and inexpensive.

4. Depending on the time of year, a grower will have to either black cloth or light the plants during production.

5. To make the plants produce vegetative growth, they are first grown under long days; if the days are naturally short, artificially light the plants from 10 p.m. till 2 a.m. Tall types will need 1 week of long days, medium types need 2 weeks and short types need 3 weeks.

6. To induce flower formation put the plants under short day conditions. If the days are naturally long, cover the plants with black cloth from 5 p.m. until 8 a.m. daily. Natural long days are from March 15 through September 15.

7. Standard production practice puts five cuttings around the edge of a 6" pot. Make sure the cuttings are leaning against the pot rim for support. They must be pinched when roots have reached the bottom of the media; usually 10-14 days after potting.

8. B-Nine, a growth retardant, may be required and should be applied when the new breaks are 1.5-2" long; usually 14 days after the pinch.

9. Below is a typical schedule for a nine week medium pot mums cultivar:

Bloom date April 2

Apply retardant February 12

Begin short days January 29

Pinch January 25

Pot cuttings January 15

K. Vegetables and herbs - Vegetables are typically scheduled like bedding plants. Tomatoes, peppers, broccoli, cabbage, etc. are all produced from seed, and the seed catalogs give the same information on germination and timing as they do for bedding plants.

1. Herbs can be produced from either seed or cuttings. The method of production will depend on what herb is being grown. There are specialty herb growers that sell rooted cuttings or prefinished plants to greenhouse growers. This is usually a very economical way for greenhouses to produce herbs since they are usually grown in small quantities.

2. Below is a typical schedule for vegetable transplants:

Sale date March 1

Transplant date February 1

Sow date January 22

Discuss proper acclimatization procedures

L. Once a crop is nearing the end of the production cycle it must be prepared for its ultimate environment.

M. Hardening off is a procedure that prepares the plant for cold temperature. This treatment is done to cool-season vegetables and bedding plants -- broccoli, cabbage, pansies. The temperature in the greenhouse may be lowered or the plants can be moved to a cold frame to harden them. During this process they will need less water and fertilizer.

N. Reducing fertilizer rates is especially important for blooming pot plants that will be used in the home environment. Under indoor conditions the plant will not be able to use high rates of fertilizers; excessive fertilizers can cause salt damage and shorten the life of the plant. Growers generally reduce or eliminate the fertilizer 1-2 weeks before the plant is sold.

O. Lowering the amount of water is important in preparing bedding plants for the outdoor environment. Let the media get drier than it did during production; this hardens the roots and prepares them for the field soil. Also, reduce the rate of fertilizer.

P. Decrease the light intensity on foliage plants. This will prepare them for the low light conditions of interiorscapes and will prevent them from dropping too many leaves. This process will take 4-6 weeks, and the light intensities should be gradually reduced. Fertilizer should be reduced at this time.

IV. Developing production records and maintaining a product inventory.

A. It is critical that every grower keep accurate production and inventory records of all crops. These records help the grower decide what crops sell well, what colors or cultivars are popular, ideal propagation dates, and target sales date. Without accurate, up-to-date records a grower will not know when mistakes have been made and will keep making the same mistakes.

B. Crop production sheets should be kept on every cultivar grown at the greenhouse. A standard form can be designed and employees simply fill in the form as the crop develops.

1. These sheets can be kept in each greenhouse on waterproof clipboards, each grower or employee can have their own record book that they carry with them, or the sheets can be kept in a master file in the office.

2. Software packages are available for computerizing production records. Many of these programs are sophisticated enough to calculate dates cultural practices should be done; pinch, disbud, apply growth retardants, etc. They will also calculate production cost, keep inventory records and handle many other factors. These programs range in price from several hundred to several thousand dollars.

3. Any software program is only as good as the person who enters the data. Data must be entered every day if accurate records are to be kept.

4. Notes on cultivar performance, insect or disease problems, physiological problems and any other observations should be kept; it could become valuable information.

5. After several years of collecting data the grower should be able to develop an accurate production plan for the greenhouse. A sample crop production sheet is shown on the following page.

Crop: v-14 Glory Poinsettia Size: 6 ½ oz.

6 Up-to-date product inventory records are necessary for accurate sales of the crop once it has been produced. Unfortunately, many growers never bother to count and keep track of the containers they have for sale. They rely on the "I saw a lot of 4" geraniums on the bench yesterday" method. When a customer calls and says they need 200 geraniums delivered on Friday, the grower says they have them and will be happy to supply them. Thursday evening the employees start packing the order and discover that there are only 98 quality pots on the bench; a major problem now exists. The 98 plants can be delivered with an apology, or the greenhouse can call the customer and tell them they don't have the plants, either way the customer is upset and probably won't buy from the greenhouse again!

C0 Inventory records must be kept during the entire production period. With accurate inventory records you will know exactly how many containers are on the bench at any given time. This accurate count of salable containers will tell you if your greenhouse has enough plants for your retail customers, if the greenhouse is short and needs to buy some from another grower, or if there are too many plants.

1 Inventory records can be as simple or as complicated as the grower desires; an employee counts the containers and writes it on a sheet of paper or a computer keeps track of what's left after each sale.