Wow! Who knew that the onion harvesting and packing process could be so intricate? I recently took a trip to Harris Fresh in Coalinga, California to see how onions are harvested commercially, including both hand and machine harvesting processes, as well as the onion packing process.
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How Onions Grow
Onions are root vegetables that grow underground. In large commercial operations, onions are planted in rows to allow for tractors and machinery to aid in the growing and harvesting process.
Why Are Onions Harvested at Night?
Onions are highly susceptible to sunburn. As a result of that and to improve worker harvesting conditions, onions are harvested at night.
At this particular operation, the hand harvest starts in the late afternoon and goes until around midnight. The machine harvest starts around midnight and goes as late as noon the following day.
Since I went during the middle of the harvesting season, I was able to see both the hand harvest and the machine harvesting process. Although they are very different processes, they do both occur at nighttime. On the day I was there visiting, the hand harvesting began at 4pm and the machine harvesting process began at midnight.
Onion Harvesting – Hand Harvest
As you can see from the picture above, it takes a lot of workers to hand harvest an onion field. Before the harvesting process gets started, there are a few preparation steps that take place first.
Onion Hand Harvesting Preparation
- Spiker Roller – The Spiker Roller clears the furrows to make it easier for the undercutter to pass through the field, and cleans off the tops of the onion plants that are located in the furrows.
- Undercutting – The Lifter Bar is responsible for undercutting. During this process, the Lifter Bar moves beneath the onion plants that are located underground, and moves the soil to lift the onions to the soil surface to help with the hand harvesting portion.
The preparation steps start approximately one hour before the hand harvest starts. They then continue clearing the field as the workers progress through the field during harvest.
Onion Harvesting Process
The harvesting process consists of the following steps:
- Bins – The workers work in pairs and each pair grabs their own bin and takes it to the section where they are harvesting. They use smaller containers during the actual harvesting portion and once those are filled, they are poured into the larger positioned bins.
- Trimming – The workers remove the onions from the field (which are now on top of the soil thanks to the undercutting process), and trim the onions with scissors. They remove the top portion of the onion plant and, in some cases, trim the bottom roots. These harvested onions are then placed into the smaller containers.
- Bin Dump – When the smaller containers are filled, they are poured into the larger bins. The workers are working at piece rate, so every time they complete a bin, they get credit for it. They then carry another bin to where they have progressed in the field and continue the harvesting process.
Onion Curing
The harvested bins are then stacked and stay in the field for at least one day prior to transporting to the packinghouse. The white onions stay in the field for one day, and the red onions stay for two. This is what is referred to as the onion curing process, where the harvested onions are left out in the field (this is a really hot region in California’s Central Valley) to dry further to help prevent pathogen growth and water loss during storage.
Onion Harvesting – Machine Harvest
Machine harvesting onions can result in a greater profit for the grower, as it is a quicker harvest with less labor. However, not all onions can be machine harvested due to the potential damage caused.
Which Type of Onions Can be Machine Harvested?
Since machine harvest is a rougher harvesting process compared to hand harvest, it can cause damage to the onions. For this reason, only the yellow and sometimes the red onions are machine harvested. Yellow onions are hardier onions, and can better withstand the mechanical harvest. At the start of the season, from June to late July, the yellow onions are hand harvested and then from the middle to end of the season, the yellow onions are machine harvested. Red onions can also be machine harvested later in the season as well, but white onions are never machine harvested.
Onion Machine Harvesting Process
There are three steps, using three different machines, that comprise the mechanical harvesting process:
- Mower – The mower goes through the field first to mow the tops of the onions. The mower does this by going above ground to remove the top portion of the onion plant.
2. Wind Roller – This machine digs the onions out from underground, passes them along a conveyor belt to remove soil and field debris, and then places the two rows of onions picked up and puts them into one row. (This placement is done to prepare for the third step.) There are workers that follow this machine to make sure that all of the onions end up in one row.
3. Top Air – The Top Air picks up two rows of onions at a time, which were originally four rows of onions during the growing season. It then blows air and the onions pop up, and are transported to the upper portion of the machine to be hand sorted by workers. The quality product is then transferred to the adjacent trailer and is then transported to the packinghouse.
Based on the speed of the harvesting process and the limited amount of workers needed, you can see how this could increase the efficiency of the harvesting process.
Onion Packing
Harris Fresh grows and packs white, yellow and red onions. In order to be able to fulfill all orders that come in for different customers, they run all three colored onions through the packing line each day.
- Bin Dump – The harvested bins come in from the field and are dumped into the outdoor bin dump.
- Conveyor – The onions that were dumped outside are transported inside to the rest of the packing line.
- Optical Sorter – The onions are placed into individual cups and pass through the optical sorter. The optical sorter works to sort the onions by size and to detect internal issues. The optical sorter is responsible for directing the different sized onions to the specific sized packing line. It also uses infrared light to detect internal issues that cannot be detected by the human eye. Every time a new issue is detected that the machine does not catch, they are able to train the machine to detect those. This results in less issues for when the product makes it to the middleman and final consumer, and prevents issues from spreading to the surrounding onions.
- Packing – The onions that were sized by the optical sorter pass down to the appropriate packing line. There are workers hand sorting to remove any additional product to go to the secondary market or to be culled. The onions then continue on to be mechanically packed into bags.
- Palletizing – The packed bags are sealed by a worker and passed on to a palletizing machine. The palletizing machine stacks the bags to form a pallet. The pallets are then wrapped and prepared for transport.
When the onions are destined for the processing market, they are bulk packed into bags. These bags measure the size of two bins, without the cost of the weight of the bins. The large pallet bags are transported to the processing plants, where they are lifted up and emptied out via a tied up hole in the bottom of the bag.
The onions are either shipped that same day or are stored in the cooler until they are shipped out. During the harvesting season, onions are harvested and packed within the same 1-2 days. As a result, there is very little cold storage of the product prior to shipment.
Check out the video below to see a complete overview of the onion packing process.
Featured Grower Information
I would like to thank Harris Fresh for the visit and for allowing the gathered content to be shared. Harris Fresh is located in Coalinga, California and grows onions and garlic. You can also click here to see how Harris Fresh harvests and packs garlic.
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I appreciate the interesting knowledge you share, gracias mi amigo. 🥕ðŸ…ðŸ
I have a question. In 1940s Texas my father worked harvesting onions by hand. Can you tell me whether something about the process would have left a lingering smell of onions on my father’s hands, body, or clothes?
Thanks,
Tom
Could you please tell me who took the photos and the names of the photos
All of the photos on this page and throughout the website and YouTube were taken and belong to The Produce Nerd (unless otherwise specified).