Romaine Lettuce

The Food and Agriculture Organization of the United Nations (UN FAO) provides global statistics for lettuce and chicory production. Romaine is a dominant variety of lettuce, but it’s important to realize that the actual romaine markets are a subset of the provided statistics below. Toward the second half of this section, we’ll provide some US-centric data from the USDA National Agricultural Statistics Service (NASS) that isolates romaine production.

The global lettuce and chicory market can be addressed in terms of total production (tons) and as the total value of production (USD.) China is the top lettuce and chicory producing country, producing approximately five times more lettuce than the US, which is the second largest producer. Other notable production regions include India, Spain, Italy, Japan, Belgium, Turkey, Mexico and France. Its interesting to note that Belgium is by far the most efficient production region, and that India, while producing substantial tonnage, has a very low yield per hectare of productive acreage. In theory, it is possible for Indian production to increase five- to six- fold without impacting productive hectarage by increasing yield.

TABLE 1: Global production of lettuce and chicory (FAOSTAT)

**The most recent available global Lettuce and Chicory GDP data from FAO is in 2020, which doesn’t line up exactly with the most recent acreage report (2021), but it is close.

CHART 1: Production Share of Lettuce and Chicory by Global Regions in 2021 (FAOSTAT)

The USDA NASS breaks the US lettuce market into three primary segments: head, leaf, and romaine lettuce. In the below report we have isolated the romaine lettuce datasets for California and Arizona, which, when combined, account for ~ are the dominant romaine production regions. (As is evident in the table below, the USDA NASS statistics exclude romaine production from the other 48 states in the US figures, making this informational useful for general guidance as opposed to anything conclusive.)

TABLE 2: Harvested acres and utilized production of romaine lettuce in the US for 2020 and 2021 (USDA NASS)

[Source] [Source 2] [Source 3]

In total, according to “Research and Markets”

[Source]

[Source]

As one of the most economically important leafy vegetable crops in the world, it is increasingly important to understand lettuce from both a domestic and a global perspective.

“Based on most recent production and price averages in the US, the estimated gross value per acre is approximately $10,400 for head lettuce. The cost of lettuce production varies depending on the location. It is labor-intensive, especially for harvest and post-harvest handling and packaging.” [Source]

[Source - Page 56 Vegetable Summary]

The total addressable market for Romaine Lettuce is an important upperbound constraint to be aware of when analyzing the market opportunity that a technical solution provider has when marketing to romaine producers. Understanding the realistic addressable market for specific technology applications (i.e., harvest automation, precision fertigation, precision irrigation, etc.) is equally critical, as it enables solutions providers to realistically determine appropriate sales pricing and costs of goods constraints. Knowing the total production of romaine lettuce and the GDP of said production on a global and geographic basis can help investors make informed decisions about where to invest, as well as inform strategic decisions about where to enter the market.

Planting and cultivating romaine lettuce is a heavily mechanized process that relies upon a direct seeder or transplanter. Typically, the equipment is attached to a tractor that is driven across beds. However, how a farmer chooses to plant the lettuce is ultimately a choice that is driven by the unique factors of their given soil and farmland.

Romaine lettuce is a valuable and important crop in the United States, but growing it is not without its challenges. Farmers must consider the environmental and seasonal conditions, such as temperature, drought, and pests, and consider the cost of production, labor, and post-harvest handling when developing their crop plans.

Typically, romaine lettuce takes anywhere from 65 to 95 days from planting to harvest depending on genetics, weather, temperature, humidity, soil types, seed depth, stimulants, endosperm thickness, and more.

Romaine lettuce—unlike its younger family member baby greens—is still hand harvested and packed in the field. The prioritization of quality control has meant that there is yet to be a machine that can out-pick a skilled picker in the field.

John Mckeon from Earthbound Farms describes the harvest and packing process as “a labor-intensive process, which is done from a harvest machine. It is from this central hub that crews (usually made up of 25-35 people) harvest and pack the romaine. Product is cut from the field by harvesters and placed on the first tier of the harvest machine.”

[Source - Earthbound farm]

Sample Costs to Produce and Harvest Romaine Hearts:

Understanding the costs and market conditions associated with producing romaine lettuce is important to growers so that they can maximize the value of the crop and ensure a successful harvest. Additionally, growers must be aware of the pest and disease control methods they can use to protect their crop and ensure a good harvest. This UC Davis research study, can be used to make production decisions, determine potential returns, prepare budgets and evaluate production loans. The practices described are based on production procedures considered typical for this crop and area, but they will not apply to every situation.

These production costs are critical for startup founders to understand because this information will help to set realistic targets for the product development. Understanding that “harvest costs” make up ~46% of total operating costs per acre enables a harvest automation startup to more realistically isolate the market value of their product and acknowledge that there likely is a willingness for most romaine growers to invest substantial (though not un-capped) operating capital in harvesting solutions.

In short, crop budgets detail the various practices involved in producing romaine lettuce, which can be summarized as follows. Land preparation, which includes discing, subsoiling, compost application, and bed cultivation, begins in October/November of the year prior to planting. The lettuce is direct-seeded using a precision air planter, and thinned to a 9-inch in-row spacing using an automated thinner. In addition to compost, fertilizer such as potassium sulfate, nitrogen, and liquid fertilizer are applied at the discretion of the farmer. Irrigation involves applying 4 acre-inches of water through sprinklers during stand establishment and 10 acre-inches through the drip system for the growing season. Pest management involves monitoring for insects and diseases and applying three to four pest management applications. Weeds are managed using herbicides and hand weeding.

Lettuce is a cool-season crop that grows best with moderate daytime temperatures of 73 degrees F and cool nights of 45 degrees F. After harvesting, lettuce should be cooled immediately in order to maintain its freshness. One method for cooling is through vacuum cooling, which brings the temperature down to 34ºF (1ºC), Product is then stored at just above freezing with 98% relative humidity. Lettuce that has been harvested at its prime maturity without any defects can be held for two to three weeks at 34ºF (1ºC). However, if stored at 37ºF (2ºC), the shelf life will be reduced to one to two weeks. There are also specific storage disorders that can affect lettuce such as russet spotting, caused by exposure to ethylene gas, and brown stain, caused by high levels of carbon dioxide in the storage area. [Source]

Because proper temperature maintenance is key to increasing shelf life and preventing storage disorders, lettuce can be an incredibly difficult specialty crop to handle post harvest.

It is critical to understand, at least at a high level, the various horticultural practices that are required to produce romaine lettuce. These practices affect product design and development efforts, and understanding them helps to provide a fuller picture of the harvest and harvest-related activities. The following activities should be looked at to help maximize the impact of harvest automation.

One common offering is a consumer package containing three romaine “hearts.” For this product, heads are harvested by hand in the field using a knife. Harvesting lettuce by hand is important to ensure that the heads are gathered at the optimal maturity and size. Hand harvesting also allows for greater control over the size and quality of the heads harvested, at least at present (June 2023) and reduces the likelihood of crop damage relative to that with mechanical harvesting. Additionally, hand harvesting can help to reduce waste, as workers can pick out any damaged or unmarketable heads. Finally, hand harvesting is generally the most cost-effective harvesting method available today for smaller crops. [Source]

The D’Arrigo Brothers’s Youtube channel features a series of very useful videos documenting lettuce harvest.

In the video below, publsihed in March 2021, one can get a sense of what fully manual romaine heart harvesting looks like.

Today, it is generally true that:

The video below displays some of the different machine and robotic technologies that D’Arrigo Bros are using and testing in their romaine fields.

Requirements/Wish List:

Lessons Learned (using currently available machines)

Ramsay Highlander has launched a new product called the Mechanical Harvester that is designed to harvest Romaine, Green Leaf, Iceberg and other commodities. The harvester utilizes Ramsay’s patented Water Jet cutting method which increases yield and product shelf life while increasing labor efficiency. It has an individual high-pressure water stream for every seed line, allowing for independent adjustment of cut height for uneven beds. The harvester also helps eliminate trash leaves before reaching the sorting/packing belt and can be configured for totes or bins. The harvester can harvest 12,000 pounds of Romaine per hour into totes and up to 24,000 per hour in a bulk loading version. This harvesting method is considered the way of the future due to its increased yield, natural sanitary cutting method and ability to negotiate uneven beds with less water consumption. [Source]

The UC Davis Cost Study done in 2019 and referenced above goes into more detail about the labor costs for producing Romaine Hearts on the Central Coast of California. The hourly wages for machine operators, irrigators and general labor in 2019 were $24.70, $20.80, and $18.70, respectively. The cost includes the employers' share of taxes, workers' compensation insurance, and other benefits. The state minimum wage and overtime regulations may result in increased labor costs. Growers can also use the H-2A guest worker visa program, but it may result in higher labor costs. Interest on operating capital is calculated monthly until harvest at a nominal rate of 6.25% per year. Equipment operating costs include fuel and lubrication, repair, and pickup truck costs. The risks of producing and marketing the crop are high, and the study cannot fully represent all the risks involved.

Mechanized crop production is becoming more common in the global agricultural industry as labor becomes scarce and more expensive. This includes lettuce production, with growers looking for new varieties that can be harvested by machine. The American fresh food industry is very dependent on agricultural laborers, but fewer immigrants are arriving in the US to take on agricultural jobs and agricultural laborers are becoming older. This development places immense pressure on growers to find innovative solutions. This is a global problem and the global aging of the farming population is increasing the need for new advanced technologies. [source]

A crew of 10 cutters and 16 packers, stackers, and drivers can harvest 2,500 to 3,000 cartons of romaine lettuce in an eight hour day. Growers guarantee all members of the crew receive minimum wage (with many harvesters often receiving much more), and offer a bonus that is shared by the crew if they harvest more than a target level of cartons, which varies by field and yield. Crew-bonus systems allow most lettuce harvesters to earn several dollars an hour more than California’s $15 an hour minimum wage, often $150 or more a day rather than the $120 guaranteed by the minimum wage.

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Incorporating a hygienic design for automation of lettuce is also an important consideration.

Lettuce crops, including romaine lettuce, are highly susceptible to damage caused by weather conditions. Although lettuce can grow in a range of temperatures, extreme heat or cold can cause significant damage to crops, affecting both their growth and yield. Strong winds, heavy rain, and hail can also damage lettuce crops, leading to a reduction in their overall yield. Additionally, soil moisture levels need to be carefully monitored, as both too much and too little water can negatively affect lettuce growth.

Heavy rainfall can cause soil erosion, leading to the loss of nutrients and the degradation of soil quality. Furthermore, excessive soil moisture can promote the growth of fungal diseases that can damage crops. Conversely, drought-like conditions can cause lettuce crops to wilt and become stunted, leading to lower yields.

Growers consider weather patterns and conditions when planning their planting and harvesting schedules. In areas where rainfall is scarce, irrigation techniques can be used to supplement the water supply and maintain soil moisture levels. In regions that experience heavy rainfall, growers may need to implement drainage systems to prevent soil erosion and control water levels.

Overall, managing weather conditions is a critical aspect of lettuce production, and growers must take measures to protect their crops from adverse weather events. By monitoring weather patterns and implementing appropriate measures to maintain soil moisture levels and protect crops from damage, growers can maintain high yields and produce high-quality lettuce crops that meet consumer demand.

[Source - NC State]

Growers must implement strict protocols to prevent contamination and ensure food safety, such as regular testing and monitoring of soil and water sources, implementing food safety measures during harvesting and packaging, and complying with government regulations. These measures can be expensive and time-consuming, particularly for small-scale farmers.

At the same time, food safety is of utmost importance as it directly impacts consumers’ health and well-being. The risk of foodborne illness is a serious concern, and consumers have the right to expect that the food they purchase and consume is safe. With recent outbreaks of E. coli and other pathogens in romaine lettuce, consumers have become increasingly aware of the need for rigorous food safety protocols. In order to maintain consumer trust, it is important that all farmers and members of the food value chain, regardless of size, take food safety seriously and implement best practices to prevent contamination.

Compliance with government standards and regulations is important to ensure that all farmers are held to the same standard, and to prevent outbreaks of foodborne illness. Compliance with these regulations can be painful and costly for farms, creating tension.

Hygience is a top-of-mind issue not only on farm, but throughout the supply chain for lettuce and leafy greens, from farm inputs to retail.

CDC has a very informative page on food safety communication specifically targeted towards leafy greens that can be used as a governmental guide.

Lettuce Harvest Video Links

The following list of videos and corresponding comments were provided by Mike Dentinger, VP at Trimble (Thanks, Mike!)

Automatic or Robotic Lettuce Harvest Videos