Hello everyone! I’m Shohei.
You’ve probably noticed that plant factories primarily cultivate leafy vegetables like lettuce, spinach, and komatsuna.
“But why leafy vegetables in the first place?”
“Wouldn’t it be great to grow a wider variety of vegetables?”
The reason is that plant factories possess certain characteristics that make them ideally suited for cultivating leafy vegetables.
This article delves into the reasons why leafy vegetables are well-suited for plant factories from perspectives such as growth characteristics and economic feasibility.
By the way, lettuce is especially prevalent. Why is that? I’ve written about the secrets behind its perfect compatibility below. Please take a look.
The Essence of Plant Factory Characteristics
First, let’s briefly summarize the core characteristics of plant factories.
Plant factories achieve year-round, planned production of crops by artificially controlling environmental conditions such as temperature, humidity, light, and carbon dioxide concentration. Unlike open-field cultivation or other types of facility horticulture, plant factories are characterized by their ability to produce crops stably with minimal impact from external environments.
Growth Characteristics of Leafy Vegetables and their Edible Portion Ratio
So, why are plant factories so well-suited for leafy vegetables? It comes down to their growth characteristics and the high proportion of edible portions.
Leafy vegetables have leaves as their primary edible part, and the proportion of leaves in the entire plant is high. In other words, almost everything that grows in a plant factory (excluding the roots) is generally edible.
Additionally, leaves grow quickly, allowing for a short cultivation period of around 30 to 40 days from sowing to harvesting.
These characteristics make leafy vegetables ideal for year-round and multi-stage cultivation in plant factories.
To put it simply, “production in plant factories is costly, so only vegetables that can be grown in large quantities with high turnover (edible portions) are feasible.”
Vegetables with slow growth rates and a high proportion of non-edible parts would lead to significant losses.
In the past, we’ve also covered the topic of crops that are “a bit too challenging for plant factories.”
For instance,
These are examples of crops that pose challenges.
As mentioned in those articles, cultivating grains and root crops in plant factories is not just challenging but rather “there’s no real advantage to growing them in a plant factory.”
Three Conditions for Suitable Vegetables in Plant Factories
Therefore, the following three conditions are considered essential for crops suited for plant factories:
- Ability to harvest within a short period with high yield per unit area.
- A large proportion of edible parts.
- Ability to control growth through environmental regulation.
Leafy vegetables fulfill these conditions.
For example, lettuce has a short cultivation period of 30 to 40 days from sowing to harvesting, and continuous production throughout the year is possible through environmental control within the facility. Moreover, everything except the roots is edible.
Furthermore, the ability to control the growing environment to alter growth is another reason why leafy vegetables are perfectly suited for plant factories. Among leafy vegetables, there are varieties with high levels of nutrients, vitamins, and minerals, offering potential for added value.
Besides leafy vegetables, fruits can also be well-suited for plant factories.
Well, not every fruit fits the bill. However, we’ve also discussed fruits in a separate article.
The Significance of Cost Recovery Rate
And undoubtedly, the biggest challenge for plant factories is their high initial investment and operating costs.
Initial investment in facilities, air conditioning equipment, lighting equipment, etc., is substantial, and running costs, such as electricity bills, are also high.
Plants distribute the sugars and other products they generate through photosynthesis to various parts, such as leaves, roots, and fruits.
When a significant portion of these photosynthetic products is allocated to non-edible parts, the resources invested are wasted. Additionally, non-edible parts are discarded after harvesting, leading to the loss of the invested costs.
In plant factories, all production resources, including light, carbon dioxide, and nutrient solutions, come with costs. Excessive losses due to uneven distribution of photosynthetic products can jeopardize profitability.
Leafy vegetables, due to their allocation of most photosynthetic products to leaves, enable efficient conversion of resources into products with minimal waste. This concentration of photosynthetic products in leaves is linked to the high productivity and cost recovery rate of plant factories.
Essential On-Site Expertise Despite the Advantages of Leafy Vegetables
While the theme of this article is “Why Leafy Vegetables Are Advantageous in Plant Factories,” the reality is that many cases of losses occur even when cultivating leafy vegetables.
In practice, it’s essential for the on-site team to understand the correct knowledge and techniques.
However, as mentioned in other articles, the scarcity of methods for acquiring concrete knowledge and techniques that lead to profitability is a reality.
If you’re looking to enhance your on-site expertise, refer to the content on this site.
The following content provides valuable insights into boosting the profitability of plant factories.
Summary
Let’s summarize the contents of this article.
The following three reasons explain why leafy vegetables are widely cultivated in plant factories:
- Ability to harvest within a short period with high yield per unit area.
- A large proportion of edible parts.
- Ability to control growth through environmental regulation.
In plant factories, where costs are high, leafy vegetables, possessing these characteristics, are the optimal choice.
In fact, it’s almost impossible to cultivate other vegetables.
The growth characteristics of leafy vegetables and the allocation of photosynthetic products perfectly align with the characteristics of the artificial environment that is a plant factory. This is why leafy vegetables are prevalent in many plant factories.
Recently, wasabi has gained attention as a crop that fully utilizes such artificial environments.
For an explanation of wasabi, please refer to the following article.
To enhance the productivity and cost recovery rate of plant factories, cultivating crops like leafy vegetables with short harvesting periods and minimal loss, coupled with the development of efficient environmental control and automation technologies, are crucial.
- What are the weaknesses of plant factories?
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The biggest weakness of plant factories is the high initial investment and operating costs. The initial investment in facilities, air conditioning equipment, lighting equipment, etc., is substantial, and running costs, such as electricity bills, are also high. Additionally, securing specialized personnel is a challenge due to the need for advanced environmental control technologies and cultivation expertise.
- What are the characteristics of lettuce cultivated in plant factories?
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Lettuce grown in plant factories is characterized by its year-round stability in quality and supply. Advanced environmental control technologies allow for planned production without being influenced by seasons or weather. It is primarily pesticide-free, making it safe. Moreover, plant factories are enabling the development of unique lettuce varieties with enhanced taste, texture, and functional components.
- What vegetables are grown in plant factories?
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Plant factories primarily cultivate leafy vegetables such as lettuce, spinach, and komatsuna. Other crops include baby leaf vegetables, salad greens, arugula, and herbs. In recent years, attempts have been made to cultivate fruit vegetables like strawberries and tomatoes, as well as microgreens, in plant factories.
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