Mechanization and Material Handling Basics

Considerable emphasis has been placed on updating growers on energy conservation and heating fuel alternatives over the last several years.  Many growers who have adopted these ideas have realized significant savings as the price of energy continues to escalate. But still the largest cost item in plant production is labor. Equal or greater savings can be obtained by incorporating materials handling techniques and mechanization into the growing operation.  

Labor efficiency is something to strive for whether you operate a greenhouse by yourself or hire many employees.  A good starting point for evaluating labor efficiency is to collect data on which operations require the greatest amount of time.  Transplanting, potting, hand watering, spacing and plant selection for shipping are some of the greatest labor users.  These tasks are the ones that should be evaluated first to see if improvements can be made.

Equipment is available for almost all the tasks that take place in the greenhouse but not all tasks should be mechanized, especially for the grower with only a small amount of growing area.  Some of this equipment is very expensive.  Other machines have use only a few days out of the year.  Purchasing decisions need to be made only after considering many factors.

• Keep things simple. An understanding of how a piece of equipment works is important. Low-tech equipment generally requires less adjustment, less maintenance and uses standard parts.  It is easier to upgrade a basic system than to replace a complex one that doesn’t do the job.  I frequently see expensive equipment sitting idle in a corner because it didn’t perform the way the grower had hoped.
• Be conservative.  Have a plan for what you want to accomplish, but limit the amount of change that you institute at one time.  Be conservative in your expectations of what equipment will do.  It may take a while to get the proper adjustments and work out the bugs.
• Analyze your needs thoroughly.  Equipment is expensive to own. Consideration should be given to where your resources will give the greatest return to the business.  For example, an automatic watering system that can be used year-round may be a better choice that a precision seeder that will be used only 10 days a year.  Compare alternatives on a simple payback basis.  Simple payback in years is calculated by dividing the initial cost of the new equipment by the savings realized per year.  A good payback is 2 to 4 years.
• Design your facility for efficient materials and plant movement. Reduce unnecessary transport, combine different tasks into one transport if possible and transport through the shortest route.  In developing a layout, decide whether the receiving and shipping should be separate or in the same location.  Provide concrete walkways to handle the volume of materials moved.
• Storage – a place for everything and everything in its place. Provide adequate space for storage of growing mix, containers, supplies, tools and spare parts.  Locate the things that are used frequently near to point of use. Label everything to reduce time spent looking.
• Mechanize or automate jobs that are repetitive, tedious or time consuming.  These are usually the easiest tasks to mechanize and result in a significant labor savings.  Considerable equipment has been developed for most of these jobs.  Container filling, plant spacing, moving plants and watering are good examples.
• Install equipment that reduces peak period labor requirements.  The spring season and holiday shipping periods are usually the busiest.  Carts or conveyors can move plants quicker than hand carrying.  These may also reduce the need to hire and manage more employees.
• Select equipment that will pace workers.  Conveyor belts work well for potting, transplanting and packaging providing uniformity and consistency.  A variable speed motor adjusts the belt speed for different operations.
• Reduce the amount of walking that employees have to do.  Walking adds considerable time to the cost of plants.  An average time to pick up or set down a flat of plants is 1.5 seconds.  Carrying or walking can be figured at 4 feet/second.  At a $10/hr labor rate, making a round trip 10’ away to place a flat of plants on a bench adds 2 cents to its cost.  Walking to the far end of a 100’ greenhouse costs $0.15.  How many times is the flat or pot handled before it is sold?
• Standardize your operations.  Keep the number and types of containers that are used to a minimum to reduce inventory and the time needed to make changes to equipment. Where possible ship in standard units such as carts or pallets.  This simplifies loading and invoicing.
• Consider alternatives to purchasing equipment.  Renting, leasing or sharing with a neighbor allows the use of equipment for short periods of time without a large investment.
• Purchase machinery that can be expanded.  The reserve capacity will be useful for growth in the business or changes in the production system.
• Select equipment that is manufactured with standard parts.  Delays in getting special parts to repair a down machine can interrupt a production schedule. Standard parts such as belts, drive chain, pulleys and sprockets can frequently be purchases locally.  Critical spare parts should be kept on hand.
• Train employees for the tasks they are to perform. Utilize experienced workers or videos to show the most efficient methods.
• Employee comfort and safety is important. Provide light (50 – 75 foot-candles), heat (60 - 68ºF) and summer cooling in work areas.  An employee rest area with lockers, tables, vending machines, refrigerator and microwave improves lunch and break times.

Applying the basic concepts to your operations is the primary way to improve productivity.  Keep these in mind as you develop the systems for handling the plants.

John W. Bartok, Jr., Extension Professor Emeritus & Agricultural Engineer
Department of Natural Resources and the Environment, University of Connecticut, Storrs, CT - 2015