Which type of pot-filling machine suits your nursery the best?

Author: Aaron Chen Date Posted:3 February 2020

To improve your quality of product, nursery potting efficiency and to save labour costs in Australia, you may be considering purchasing a pot-filling/potting machine that will speed up the workflow and save wear and tear on your workers.

There are different types of potting machines in the market that could help you with filling pots. They fall into 3 categories:

This report will look at the mechanical machines in items 2 & 3. These tend to be considerably more expensive and it is very crucial to find out which type of potting machine will suit you the best, as it will be a large asset investment that may or may not give you a return on your investment (ROI) for 2-5 years

Let’s look at how a potting machine works first (in simple terms).

Operators set a certain speed rate on a potting/pot-filling machine, which then drops potting media from a hopper, into the empty pot held under the chute. Staff then manually inserts the plant and the potted plant is transported out into the nursery.

Semi-automatic potting machine

A semi-automatic potting machine has a hopper which is filled with potting media by using a front end loader/bobcat or a conveyor from a feeder storage bin. After setting up the pot filling speed rate on the machine, the soil then drops down from a chute. The worker places a pot under the chute and lets a small amount of potting media fall into the pot to cover the bottom. The worker then places the plant into the pot and returns the pot to the filling platform to be filled with soil. Alternatively the pot is completely filled and a hole is made to insert the plug or cutting into the pot. This is called “pricking out”. Thereafter, the potter puts the pot on a tray or onto the waiting trailer. The process is then repeated with the next pot.

Usually a semi potting machine can accommodate a wide range of pot or container sizes (due to the absence of a pot dispenser). Staff only need to adjust the rate of soil flow so the soil media doesn’t get over processed and damaged. Some machines do have foot pedals and stop and start as needed. Most semi-automatic machines excess or split soil is recycled back through the machine for reuse.

Automatic potting machine

Automatic potting machines fill empty pots with media, drill a hole for insertion of plant stock and moves the media filled pots to a point where plant stock can be manually or robotically inserted. There are usually options for an automatic pot dispenser with a pot loading conveyor, also for attaching an automatic fertiliser dispenser for “dibbling”. A take-off conveyor is used to deliver potted plants through a watering tunnel (optional) to either an accumulation table or for loading onto a trailer. This is usually done manually but in some cases where there are very high volumes a loading robot can be used to fill rolling benches or trailers.

Which type of potting machine to Choose in Australia?

According to the research from HRDC, the labour time required for production of potted plants in the Australian nursery industry is much higher (by approximately 100%) than the time required for production of the same number of potted plants in European nursery production systems in the year 2000. The research result also shows one of the main reasons for the potting production inefficiency is the low levels or the inappropriate use of mechanisation equipment.

As Australia nurseries try to catch up with Europe in nursery potting production efficiency, choosing the right potting machine becomes very critical.

Semi-automatic potting machine OR fully-automatic potting machine?

According to the Horticultural Research and Development Corporation (HRDC), there are 9 separate processes for the plant handling activity:

Handling plant stock – after the plant is picked up from the hardening off area and before the plant is placed into the pot with media.
Handling pot - handling empty pots before filling the pot with media.
Handling fertiliser - handling fertiliser during the overall potting event.
Handling media – after media is loaded to the hopper and before media is placed into the pot.
Handling pot with media - before plant stock is inserted into the pot.
Handling potted plant – after the stock plant has been placed in the pot and before the pot is placed in the growing area.
Handling other materials - any action associated with trays, trolleys, trailers, stakes, labels during the potting process.Maintaining potting area - any cleaning action or setting up machinery used for potting.
Preparing growing area - prepare growing area for newly potted plants.

By utilising a semi-automatic or fully automatic potting machine, handling media and handling pot with media must become more efficient. However, to choose a potting machine that can truly improve your potting production efficiency and reduce your labour cost, largely depends on the size of your nursery.

Who should choose a fully automatic potting machine?

Ask yourself how are you going to address the above situations 1 to 9 to get a return on your investment (ROI)?
How many staff am I going to need to run the machine at its high rates versus the costs of all the options?
What other equipment and utilities is needed to keep up with the automatic machine?
How often am I going to use the machine to its optimum output?
How long is it going to be idle?
What is your volume of pots per day required?
Is your plants (pots) size various or within a specific range?

For fully automatic potting, the number of staff involved to operate the potting machine can be reduced due to the amount of automation purchased. Hence, the labour cost can also be greatly decreased.

However, don’t forget the more complex a machine the more supporting services are required for maintenance. Regular service is critical because if a machine breaks down when in full production, the cost and inconvenience is enormous.

As the HRDC report states, one of the common potting production problems in Australia is that large investment in production equipment is not reflected in the labour cost per pot achieved. Therefore, if not properly planed and organised, your investment in a potting machine may be wasted

Large nurseries (over 15 staff) usually require high volume potting production so a fully automatic potting machine is usually a good fit. Automatic potting machines can only accommodate a specific range of pot sizes and may take some time to setup but they have an advantage of a very high production rate.

Large nurseries tend to own an automatic potting machine as well as some semi-automatic potting machines for the special low volume potting runs, for odd shaped containers or where volumes of plants need “potting up” is low. In other words, a semi-automatic potting machine for lower volume production may also be necessary for big nurseries. See below.

Who should choose a semi-automatic potting machine?

A large nursery usually has a variety of species of plants which use different sized pots, so when it comes to changing pots and plants types during the potting activity, a semi-automatic potting machine is generally more efficient than a full automatic potting machine. Semi-automatic potting machines can usually efficiently cater for various sized & shaped containers from small to large during the potting event.

In small (1-5 staff) and medium size (6-15 staff) nurseries, potting staff are usually not being fully utilised because the tasks of inserting pots onto the machine or placing fertiliser into pots generally involves a full-time staff member. It is difficult for the pot inserter or fertiliser inserter to contribute to any other tasks, so the labour cost per pot is too high.

However, the labour cost can be decreased by reducing the speed at which the potting machine runs. When machine speed is reduced, the number of staff required to operate the machine can be reduced because staff can now manage extra tasks and the potting tasks can be spread over fewer people. The daily production of pots will also be slightly decreased but this will be offset by the decrease in labour costs.

Semi-automatic machines are only as fast as the staff.

Semi-automatic potting machines should not be discounted. They are not only suitable for large nurseries but also for small and medium sizes nurseries.

In conclusion

Australian nurseries must carefully consider their requirements and ROI and not just think a automated machine will be better! In order to improve nursery potting efficiency, automatic potting machinery is suggested for the larger nurseries (over 15 staff) while semi-automatic potting machinery can be a better idea for all sizes of nurseries in Australia.