August 2003

Nexus Greenhouse Systems: The XY System By Bridget White

This automated system allows a grower to know where every plant, flat or bench is located on this grid and to quickly access product using grid-based automation. This is very important to growers who produce a large number of varieties and are dependent on a very compressed shipping season.

OK, so what is XY? It doesn’t sound like any sort of automation U.S. growers have ever used. Our automation has very pragmatic names like transplanters or flat fillers or conveyers.

In short, XY refers to the coordinates on a grid system (think back to high school math). This automated system allows a grower to know where every plant, flat or bench is located on this grid and to quickly access product using grid-based automation. This is very important to growers who produce a large number of varieties and are dependent on a very compressed shipping season.

In any U.S. production facility, product is moved from the growing area to the shipping area to the customer in large quantities, sometimes consisting of hundreds of varieties. In an XY-equipped greenhouse, when a plant is selected to be shipped, a robot or overhead crane will “find” the carrier by consulting the computerized location system and bring it to the shipping area. This system is fast, safe and labor efficient and holds great promise for the U.S. market, and Nexus Greenhouse Systems has just introduced it to the U.S. market.

I actually saw the first XY components being manufactured a year ago in The Netherlands during Hortifair and found it to be fascinating in the opportunities it affords growers. In fact, Visser, manufacturer of the XY system, technicians transported the actual system I’ll be discussing below into a neighboring field to show us how it operated and to test it one final time before delivery.

System Basics

This system for the transportation and growing of plant product consists of three basic elements: X-transporter, Y-transporter and a loading/unloading system.

The core of the XY system is a pick and place unit that removes growing material from greenhouse bays (the Y direction). The unit is driven by an operator and can selectively pick product from anywhere in each bay. It rides on steel rails into the bays, eliminating the need for a concrete floor. During peak shipping periods, the pick and place unit can comfortably clear two acres of greenhouse in a single day. Small overhead cranes can also be used (in a totally automated option) in both new and existing operations, as most greenhouses have enough gutter height to accommodate a crane.

The second part is the mechanism to move material to and from the greenhouse, headhouse and shipping area (the X direction). The transport robot rides on a concrete transport aisle and is electrically powered with no operator.

A compare and contrast of the different functions of these two items might facilitate understanding.

* The Y-transporter only moves into and out of the bays of the greenhouse; the X-transporter runs on the center path between bays and the headhouse.

* The Y-transporter picks up the plant carriers, as an example, in the greenhouse and drives onto the X-transporter, which is waiting on the center path for the carriers. The X-transporter takes the carriers to the loading station while the Y-transporter picks up a new load of carriers.

* When the Y-Transporter needs to go to another bay, it moves onto the X-transporter and together they drive to the required bay, after which the Y-transporter drives into the bay to pick up a load of carriers. And the process starts all over again.

The third part of the system is the carrier (whatever holds the flats, packs or pots). The XY incorporates carriers specially designed with racks the same size as cart shelves, which can stack on a traditional cart base and serve double duty as shipping carts. Less expensive carriers can be designed that do not have the dual function.

The First Installation

Unlike many pieces of automation, the Nexus-Visser XY system has been manufactured with the U.S. grower specifically in mind. It has the flexibility to accommodate the large numbers of varieties and pot sizes common in U.S. greenhouses, and growing containers can easily be converted into that all important grower headache: transport carts.

It might sound odd to say that the first installation of a piece of automated equipment specifically designed for the U.S. market took place in England — Chichester, England to be exact — but it did. Roundstone Nurseries, a wholesale grower located in the South of England and a producer of 26 different species and hundreds of cultivars, has worked in close cooperation with Visser for almost 20 years and, as a close-to-home version of U.S. production, Visser thought the Roundstone facility was a logical first installation.

Starting from a green field or a completely new site, as Fred Milbourne, owner of Roundstone Nurseries says, made their application a simple matter of designing the site and installing the equipment. Milbourne considered other systems, such as a container bench system, but ultimately decided on the XY because they “felt [it] would suit our requirements better. It’s more flexible, gives better access to the crop, better utilization of space and is faster,” explained Milbourne.

The Roundstone installation was completed in January 2004, just in time for full spring production using the new system. “We worked with it 24 hours a day, seven days a week,” boasted Milbourne, “so the learning curve was very steep. We are very fortunate to have good people in operations and engineering, so we managed, I think, very well.”

“First of all,” continued Milbourne, “the installation went very well. Visser came in on time and finished on time. From that point there were absolutely no problems. To say that we had no problems once we started running the system at capacity would not be true, but I think you have to ask yourself with an installation of this size, what is an acceptable level of problems? We had some component failures within the equipment that were quite easily fixed by our own engineering team and supported by Visser’s, and we had some software problems. However, none of these problems interfered or brought production to a standstill, which I believe is the most important thing, and I think this is almost inevitable with an installation of this size.”

Good to Know

An XY system is not the cheapest piece of automation you can go with, and it’s not for the faint of heart. This is serious automation for growers who move a serious amount of product, and the cost is in line with the level of sophistication. The estimated cost for the components described above, plus the dual-use carriers, is less than $3.50 per square foot. In a situation such as Roundstone’s, it’s hard to determine exact equipment cost or even payback, as all costs are bundled together, but the anticipated payback for the entire project, including the automation, is a quick 3-4 years, but there are many design options available, with costs varying accordingly.

As Mike Porter, president of Nexus, said, “Each system is unique in some way as it provides a match between available automation equipment and the grower’s individual needs.” The amount of planning that is put into the design of the XY system has a “resulting increase in efficiency, quality and profitability that’s hard to measure.”

The XY System will make a significant change in how many customers will do business. It is a system that makes sense and has been thought out very well. Working with the Nexus team, a grower can design a new project or redesign an existing one that incorporates all or parts of the total XY.

The XY system is manufactured by Visser International Trade and Engineering, the largest supplier of machines and systems for the horticultural industry, and distributed in the United States exclusively by Nexus.