The process of growing, storing and packing of sweet potatoes is really interesting, especially when you consider that there is only a few month harvesting window for California grown sweet potatoes and the growers have supplies of multiple cultivars to send out all year-round. I recently visited A.V. Thomas Produce in Atwater, California to show you the sweet potato harvest and packing processes.
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Where do Sweet Potatoes Grow in California?
Although it is not widely publicized, there is a prime sweet potato growing region in California’s Central Valley. The climate and sandy soils (it really feels like you are at the beach when walking through the growing areas) make it so that sweet potatoes can be successfully grown between the small area of Turlock to Merced. During my visit to A.V. Thomas Produce in Atwater, California to see their sweet potato harvest and packing operations, there were multiple sweet potato packinghouses all located within a few blocks of each other.
How do Sweet Potatoes Grow?
Sweet potatoes grow underground, with vines that grow above ground. They also grow in bunches, so that when they are harvested, there are multiple sweet potatoes per plant. As you can see in the picture below, there are multiple sweet potatoes and just four different plants that were harvested.
Preparation for Sweet Potato Harvest
There are two steps that take place before the actual harvesting process:
- Drying out the field – The irrigation is shut off to the plants to harden the skin to decrease the amount of damage caused during harvest.
- Vine cutter or Destemmer – A tractor either goes through the field with a vine cutter, which is a large mower that takes off the vine, or with a destemmer that pulls the vines from the sweet potato plants.
Sweet Potato Harvest
When it is time to harvest the sweet potatoes, a harvesting crew goes through the field. How the harvesting process is set up, there is:
- A tractor hauling a one row mechanical chain digger (harvesting machine)
- The harvest crew is located on the harvesting machine
- Each worker has their own bin and they are looking for a specific size/grade of sweet potato
When the harvesting machine digs into the ground, it brings up the different individual sweet potato plants. They roll up the conveyor, which helps to release excess soil. They do have adventitious roots on them (all of the excess material on the potatoes), and those will stay on until they are removed during the packing process. The workers then work their way through the plants. In the example in the video below, you will see that the workers at the front are selecting the larger potatoes and then place the plants back onto the conveyor for the workers behind them to get the smaller potatoes from the plants. When their bins fill up, a forklift will come through the field to remove and replace the bins.
Sweet Potato Cooling & Storage
Once the bins are removed from the field on the day of harvest, they are placed in the 58°F cooler. When an order arrives for that specific size/grade of the sweet potato cultivar, the bins are removed from cold storage and the sweet potatoes are brought to the packing line.
The sweet potatoes can be kept in storage for many months. This process is what allows for sweet potatoes to be available year-round when they are only harvested a few months out of the year.
Sweet Potato Packing
The sweet potato packing process is a bit different than what we are used to seeing. Usually, everything is automated and it is a quick process through the packing line. However, with sweet potatoes, the packing line moves a little bit slower.
The sweet potato packing process is as follows:
- Bin Dump – The bins of sweet potatoes are dumped into sanitized water to alleviate any damage (e.g., bruising) as a result of the bin dump.
- Drying – The sweet potatoes pass through a drying step. There is a propane dryer that is a part of the packing line that is used to remove excess moisture from the potatoes.
- Packing – Here is where time slows down. Each sweet potato needs to be individually handled to remove any excess parts (e.g., adventitious roots). The workers then pack each sweet potato into the appropriate box, depending on the grade/size of the sweet potato.
- Quality Control – Once the boxes have been filled, the final boxes are weighed to make sure they meet customer specifications. If they do not, more sweet potatoes are added until they do. If they do, the boxes are closed, palletized and taken to the cooler until transport.
Sweet Potato Harvest & Packing Video
See the video below for an overview of the sweet potato harvest and packing processes.
Featured Grower Information
I would like to send a big thank you to A.V. Thomas Produce for the tour. A.V. Thomas is a sweet potato grower in the main sweet potato growing region in California of Atwater, California. Not only do they grow multiple sweet potato cultivars, they are also the sole growers on the west coast of the Stokes Purple Sweet Potatoes.
You can click here to read A.V. Thomas Produce’s expert advice on how to select and store sweet potatoes.
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Just great always wanted to know how sweet potatoes were harvested!
Thank you! It really is such an interesting process!