Stacked growing systems use vertical space, but they could be way more efficient
One technique that is currently being used in the soil-less growing industry is the use of stacked racks containing multiple levels of NFT channels or DWC troughs. This technique allows the producer to take advantage of the vertical space in their production facility, resulting in higher crop densities and the ability to supply more produce to the market.
On first glance, this makes a lot of sense. However, when we take a closer look we find that this arrangement may be losing out on the biggest productivity gains of all: labor.
Labor simply cannot be overlooked. In many businesses, labor may be the single largest cost of doing business. When it comes to labor, we have found that vertical plane systems outperform horizontal plane systems (even if they are stacked).
In this video, Nate delivers an analysis of vertical plane production versus a stacked rack scenario. If you are following the vertical farming discussion, keep reading to find out why we believe that vertical plane production provides a labor advantage over stacked NFT racks.
Each facility and its equipment is different in production ability and labor needs. This analysis will focus specifically on a stacked rack system that relies on scissor lifts and ladders for worker access. Our conclusions are based on patterns we have seen in this type of system.
Why we advocate vertical plane farming vs just stacked plane farming
In an industry that’s still experiencing the growing pains of rapid innovation, the definition of “vertical farming” can be rather nebulous. We have come to describe our ZipGrow™ technology as “vertical plane” production, or true vertical farming, since the crops are actually growing out the side of a vertical tower. This is in contrast to horizontal NFT channels or growing trays that are stacked vertically on a rack system.
For the farmer, the goal of vertical farming is to maintain high productivity while reducing upfront capital expense and ongoing labor costs. Many stacked rack systems require hundreds of thousands of dollars of expensive equipment, including rack systems, multiple layers of LED lighting, and scissor lifts. We argue that the efficiencies that you gain with this equipment are lost to the high cost of labor.
(Some entrepreneurs have gone on to build mechanized stacked horizontal systems that bring the plants down to floor level for routine tasks. The problem is that any mechanized systems that rely on automation on a horizontal basis are costly to build and operate. They often require sophisticated financing arrangements to launch. Even if one were to succeed in financing this facility, as we have seen recently, we argue that the ongoing labor costs make the system inefficient.)
Vertical farming for the regular person
As we discussed in a previous article, using ZipGrow™ Towers for vertical farm production can offer several advantages over a stacked tier system. Compared to a 3- or 4-tier stacked rack system, the ZipFarm™ offers:
- Lower upfront costs than expensive racks and scissor lifts
- More productive growing space per square foot
- Air flow and humidity is more manageable, leading to healthier crops
- Visually inspecting crops is much easier
- Minimized health & safety risks to workers (nearly all work can be done with both feet on the ground)
These are all important considerations. But there is another consideration that is harder to pin down: labor costs and workflow. Let’s take a closer look.
Labor: cost of access
The first variable we want to look at is something we call “cost of access”. This means all the time a worker will spend walking, riding in scissor lifts, retrieving growing channels, checking the crops, etc. This is time spent simply getting to the crops. In traditional agriculture, this would be done in the dirt, with a worker walking down the row, bending over for seeding, weeding, or harvesting the crop.
With modern vertical farming, cost of access can look quite different. In a stacked horizontal plane system (like a a stacked NFT system), this work may include walking down the rows, bending over to reach lower levels, using a scissor lift to reach higher levels, pulling crop channels out onto the workbench, et cetera.
These changes in the growing process take on additional importance when you consider that the worker will need to access the crops several times throughout the crop cycle. This means the worker must access the crops for transplanting, visual and manual maintenance, pest control or spraying, and harvesting purposes. This process has to be repeated for each level of the rack system, and relies on a scissor lift for anything over four or five feet tall.
The bottom line: Scissor lifts are not cheap, they are slow, and they force you to add wider aisles for navigability (and they can be very dangerous to operate). If labor costs are a concern to you, it will be worth your time to understand these variables.
Product to the Process
The ZipRack™ was designed to give you mobility in the way you transplant or harvest your crops. You may choose to roll a workbench out onto the floor for maintanence and harvesting, or you may choose to roll the growing rack to the workbench. We call this taking the product to the process.
A single worker is able to roll a rack system with up to 30 vertical growing towers to the workbench for routine tasks. Once you reach the workbench, each ZipGrow™ Tower pops out quickly and easily to be worked on.
This means that all the tools and equipment necessary for working your crops can now stay put. You will not have to take a stack of boxes out onto the production floor with you. You won’t have to walk back to the propagation station to retrieve more transplant trays.
This scenario would allow workers to work uninterrupted at the harvest/transplant station where they have all the tools and equipment necessary to do the job within arms’ reach. Using this method, a harvesting or transplanting team can work without continually walking back and forth to retrieve more materials or supplies for their work.
We believe that efficient workflows like this are the future of indoor growing, and we have designed our equipment to take advantage of these efficiencies.
Re-entry interval (REI)
If you rely on pest treatment or spray, the time you wait before re-entry can place a limit on your productivity. If a part of the system needs treatment by fogging, for example, a stacked system manager may have to shut down a large part of the system (or the whole thing) to apply the treatment. A mobile rack system allows you to roll the rack into an enclosed tent area for spraying. This means that the treatment area is off the production floor, and you will not have to close down your production floor after a pest treatment.
The flexibility that a mobile rack offers can save you many hours of lost productivity due to pest treatments.
So what does labor look like in a vertical plane system?
Let’s take a look at how a normal worker plants or harvests a ZipFarm™.
- Disconnect the easy connect plumbing.
- Roll the rack to the workbench. A rack can contain up to 30 towers, and is easily handled by a single employee.
- The workbench is located near all the relevant equipment and supplies to do the job without interruption. This includes:
- a bench for working the ZipGrow™ Tower
- the propagation station and all the seed transplants
- harvesting equipment and boxes/packaging equipment
- located near cold storage if necessary
- Remove each tower one by one and place on the bench.
- Complete the task, whether transplanting or harvesting.
- Then roll the rack back onto the production floor.
- Reconnect the plumbing, and move on to the next one.
Your farm has specific and unique needs that should be met specifically and uniquely. If you’re growing greens and herbs hydroponically, it’s likely that ZipGrow™ is the best option for you. Overall ZipGrow™ continues to demonstrate market superiority in a variety of situations.
These advantages are not accidental. We designed the ZipFarm™ to give indoor growers an edge in their labor efficiency. The productivity gains that we describe should be a significant factor in the decision between vertical plane production and stacked rack systems.