PLANT SCIENCES 330 - PLANT PROPAGATION

MIST SYSTEM PROJECT - 2000

One of the most important factors in successful propagation of cuttings is the ability to provide a suitable environment through the use of a properly regulated intermittent mist system. Misting allows for the maintenance of high relative humidity during the rooting period. Intermittent mist provides a cooling effect as water is evaporated from the leaf surface of the cutting. High relative humidity and cooling surfaces allow transpiration to be reduced while photosynthesis continues the production of carbohydrates necessary for rapid development of roots.

Many times nursery owners/managers would like to experiment with propagating of their own plant material, but are too busy or too distracted to design a mist system. This is often true in small companies or in situations where cash flow is a problem. Often a college-educated Horticulture graduate is able to make him/herself indispensable in such a company by being able to design, build, and maintain the propagation facilities. Knowing the function of each of the system components also allows the propagator to adapt individual parts to any specific situation (for example a nursery in a poorer country, where there is no electricity, or where the plant material differs in some respect and has different requirements).

PURPOSE OF PROJECT: To design an intermittent mist system, and prepare an itemized cost comparison for the different choices of components.

You have just completed your horticultural degree at Old Glory State University and upon being hired at Smith's Garden Center, you have been requested to prepare an itemized cost analysis for the building of a new propagation facility. The owners are glad to have hired someone of your educational level, and have no time for the details of this project. Moreover, if the propagating system is successful, you will be appointed as Chief Propagator. After looking over the situation, you note that a bench is available in the greenhouse, there is a 110 volt socket nearby, and the water line is located at the end of the bench. Given the following information, design and calculate the costs of the intermittent mist system based on the most recent catalogs of the major horticultural/greenhouse supply houses.

Given:

1. The existing bench is 6 ft x 60 ft long

2. The water pressure at the intake valve is 35 - 50 psi (pounds per sq inch). Nozzles must work in this range of pressure.

3. The main water supply is a well and a backflow preventer is in place.

4. The 1" spigot is located at the end of the bench.

5. Because of the width of the bench, it will be necessary to install

2 lines of pipes containing mist nozzles.

6. The choice of attaching the system below or above the table is up to you.

7. Only one zone will be needed at first, but you want to allow for the possibility that more zones (on other tables similarly set up) may be needed in the future.

8. The system must be able to be "on" for increments in seconds.

9. Nozzles can emit anywhere from 8 to 50 gallons per hour each; best is somewhere in between. Sprays should overlap by their radius, thus -

A. Calculate the following: 60 points

1. Total cost of the Delivery Equipment needed for one table, starting from the main water line (Table 1). This might include, but is not limited to the following: ** 24 volt solenoid, bypass valve, strainer, PVC pipe (the same thickness as the solenoid), elbows, tees, risers, adapters or inserts (changing PVC pipe size and threads to accommodate the nozzles) end caps, and nozzles. How will you cut the PVC? How do the lengths connect - do you need glue, tape, wire?

2. Total cost of a Controller system (Table 2) ** all the Delivery Equipment (Table 1)

PLUS a 110 volt 24-hr time-clock, a 24 volt transformer if not included in time clock, a 24-volt mist controller (also called a repeating timer), or a computer set up that will perform the required functions. Don’t forget wire and other hardward.

3. Total cost of a Mist-a-Matic system (Table 3) ** all the Delivery Equipment (part 1)

PLUS a 110 volt 24-hr timer, 24 volt transformer, a Mist a Matic, and wire. How will this connect to the solenoid?

**The following pages have charts and prices for your use.

B. Write a short narrative telling why you chose what you did and what you have in mind. - 10 pts.

C. Submit a Scale Drawing of your system (top and side view). – 15 points.

Show water and electrical sources. Label all parts, pipe sizes, indicate spray patterns, show dimensions on all. This is a schematic scale drawing.

D. Answer the following questions on another sheet of paper. - 15 points

1. Which of the 2 control types/systems is cheaper initially?

2. Which would you recommend knowing that you may have 6 tables in the future, each needing a different misting schedule? Why?

3. If a 5’ x 75’ bench/bed has a rigid stable bottom, and sides that are 4" high, how much (volume) of media can it hold?

4. If you choose to use a mix which is 1/3 perlite ($15.50 for 4 cu ft) and 1/3 vermiculite ($16.35 for 4 cu ft) and 1/3 sand ( free), how much will you spend on rooting medium to fill the table noted in Q. 3, the first year?

5. If most cuttings can be spaced so that 64 cuttings will fit into a square foot of bench space, how many cuttings are you able to stick on the bed of Q. 3 and 4 at one time?

6. If a nozzle delivers 32 gallons per hour, but is only on for 10 seconds every 5 minutes, how much water will each nozzle use in a 14 hour "misting day"?

7. Given the same nozzle as in Q. 6, how much water will all the nozzles (on the table in the project that you just finished) use per day?

NAME______COMPANY______

MIST SYSTEM ESTIMATES

DELIVERY EQUIPMENT - TABLE 1
Trade Catalog or Supplier / Item # / Description / Price/
Unit / Quantity
Required / Total Cost
Shipping costs
TOTAL COST FOR DELIVERY SYSTEM
TIME CLOCK or CONTROLLER mist system - TABLE 2
Trade Catalog or Supplier / Item No. / Description / Price/Unit / Quantity Required / Cost
+ Shipping costs
TOTAL COSTS for TIME CLOCK set up
PLUS DELIVERY EQUIPMENT TOTAL from TABLE 1
TOTAL COSTS for a TIME CLOCK MIST SYSTEM
MIST-A-MATIC system - TABLE 3
Trade Catalog or Supplier / Item No. / Description / Price/Unit / Quantity Required / Cost
+ Shipping charges
TOTAL COSTS for MIST-A-MATIC set up
PLUS DELIVERY EQUIPMENT TOTAL from TABLE 1
TOTAL COSTS for a MIST-A-MATIC MIST SYSTEM