Keys to efficient potting and transplanting By John W. Bartok Jr.

Organizing and mechanizing the potting/transplanting operation can increase production and decrease the number of workers needed.

To be efficient, potting and transplanting should be considered as part of a systems approach to growing plants. Depending on the size of the business, and the number and type of containers you use, it can be a simple system with hand labor, a fully mechanized system or combination of both.

In 1913 when Henry Ford decided to manufacture the Model T, he developed the assembly line concept. It brought the work to the workers, eliminating the worker moving to the work. With 84 tasks, each worker specialized in adding one part or component. It reduced the amount of time to build the car by over 50%, and the subsequent cost.

Growing plants is basically an assembly process of combining growing mix, container, plugs and a label — a much less complex process than assembling a car. Each of the tasks can be done by hand or can be mechanized with machinery. The potting/transplanting operation is just one of the steps that is needed.

Automatic transplanters speed production allowing more growing space to be filled in one day. (Photos courtesy of John W. Bartok Jr.)

Recently a grower told me he reduced the transplanting cost by 40% by moving his perennial transplanting operation from a trailer in the field to a mechanized system inside a headhouse. This included moving the plants to the growing area on carts.


For small batches of plants, use a workstation as an area where an employee does a series of repetitive tasks — for example, filling containers, dibbling, transplanting/potting and tagging. The layout of this area can have a large influence on the efficiency of the work that is accomplished. The following are some guidelines.

Workstation Height: The best table height is elbow height while standing. Adjustment should be provided for different sized workers. It is best to provide for both standing and sitting positions as greater efficiency is achieved when workers change positions. Height adjustment of the stool can bring the worker up to the standing height level.

Hand and Arm Motion: Where possible, both hands should operate as mirror images and both be working at all times. The reach from the normal arm rest position should be limited to a 24-inch radius to the side and front for women and 27 inches for men. Assembly area is best within 16 to 18 inches of the resting elbow position. Try to avoid lifting, and instead slide the container.

Location of Materials: Locate materials as close to the work area as possible. A space of 3-by-3 feet is normal for the worker. A pallet of prefilled containers next to the workstation saves walking. Walking 10 feet to pick up or set down a tray or carrier adds 3 cents to the production cost of the tray. Tipping the tray toward the transplanter can reduce the reaching distance by as much as 10 inches. Plugs should be dislodged to facilitate easier removal. Placing a conveyor so that the tray or pot can be pushed on is best for sending a transplanted container to a collection point where it can be loaded onto carts.

Pacing Workers: A more efficient system is to install a container filling machine followed by a transplant conveyor. As the trays or pots move by, the workers stick the plugs or cuttings that are located within arm’s reach. A variable speed motor on the conveyor adjusts the speed from 5 to 50 feet per minute to adapt to the type of container, the number of plugs/containers and the experience of the workers.

An accumulation table collects planted trays for forklift transport to growing areas.

Transplant conveyors are available in several widths — 8 inch, 12 inch and 18 inch — and in lengths to accommodate four to 24 workers. Tray supports are usually adjustable to accommodate the worker’s needs. A counter can also be added to keep track of the number of containers completed.


A pot filling machine can also be substituted for the tray filler. Mechanical potting machines usually contain a soil hopper that holds 1 or more cubic yards of mix, a conveyor that lifts the soil and drops it into the pots, a pot conveyor with holders for each size of pot, and controls that regulate the speed of the conveyors. Accessories that may be added include pot dispenser, soil compaction and leveling devices; dibble or drill for the plants; return conveyor for excess soil; and a take-off conveyor for planted pots. Machines are available that will handle containers from 2.5 inches to 21 inches in diameter. The machines fill and prepare the pots and transplanting is done by employees as the pots pass in front of them on a belt conveyor.

Once the containers are transplanted, they can continue through a watering tunnel and tagging machine before being transferred to carts to be transported to the greenhouse. Additional workers are needed to set the containers in the growing area.

I recently observed a system with a bale breaker, pot filler, transplant conveyor and watering tunnel operated by 10 workers potting 30 12-inch baskets per minute (one person on pot filler, three sticking plugs, three attaching a hanger, two labeling and one loading the cart). At $14 per hour pay, the labor cost is only 8 cents per basket. For larger operations or for growers who are producing plants year-round, there is an automatic transplanter that will fit your needs. Machines are available that will plant from 10,000 to over 50,000 plants per hour. Automatic transplanters are available with a lot of features that may or may not be needed. When selecting an automatic transplanter, consider the following:

• Select a machine that has a production rate that will match your production needs and schedule. One of the greatest benefits to having a transplanter is that you can refill growing areas quickly.
• How quickly can the machine be changed to handle a different size container, different cell configuration or a different plug size? Will the transplanter handle hanging baskets, patio pots and bowls? Will the machine plant multiple plugs in the same pot?
• Can the picking and planting depth be changed easily? Are the plugs damaged during handling? There are several designs for grippers, including multiple needles and different styles of external grippers. Some machines incorporate a plug ejector to loosen it before the gripper holds it.
• How many employees are required to operate the machine? Basic machines may require an operator and several persons to supply and remove the pots or trays.
• What information will the transplanter computer system retain? Number of flats, size of flat, cell configuration, variety of plant, etc. This information helps in planning future crops.

Manufacturers usually require that sample containers and plugs be provided for testing on a machine before it is delivered. This helps to design the right number of grippers and the position of plants in a multi-plant pot.

An automatic transplanter may require you to adapt your production system to handle different plug or tray sizes. You will also have to purchase or grow uniform plugs that are at the right stage of maturity. If plugs are not uniform or if there are skips, hand patching will be required. If a limited number of containers of a particular variety is needed at one time, it may be more efficient to do the potting by hand. With a new price of $20,000 to more than $100,000, automatic transplanters are generally economical for medium to large growers.

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John W. Bartok Jr.

John W. Bartok Jr. is an agricultural engineer and emeritus professor at the University of Connecticut. He can be reached at