Why is lettuce production overwhelmingly high in plant factories?

Hello everyone! I’m Shohei.

These days, you can find lettuce from plant factories in almost every supermarket, right?

When I started working in a plant factory over 10 years ago, it was only occasionally seen.

Currently, leafy greens, especially lettuce, are the main crops in plant factories. Here’s the breakdown for artificial light-type plant factories:
As you can see, it’s mostly lettuce.

I’ve been working in plant factories for over 10 years, and lettuce has always been a staple crop.

Plant factories are synonymous with lettuce, right?

So, let’s discuss why plant factories have become so focused on lettuce.

Well, in reality, leafy greens in general are well-suited for plant factories.
I’ve written about it in the following article, so please check it out as well.

Current Status of Plant Factories and Lettuce Cultivation

A key feature of plant factories is their ability to achieve planned production unaffected by weather, thanks to environmental control technology.

Furthermore, temperature, humidity, and CO2 can be controlled to create the optimal environment for plants.
Being isolated from the outside, the occurrence of pests and diseases is also suppressed.

On the other hand, lettuce is a representative leafy green.

It’s an indispensable ingredient in salads and sandwiches, with stable demand throughout the year. However, lettuce is easily damaged, requiring meticulous quality control.

That’s the background.

So, in conclusion:
The reason many plant factories have focused on lettuce cultivation is that lettuce’s growth characteristics match the characteristics of plant factories.

What does that mean?
Let me explain.

Lettuce’s Growth Characteristics Suited for Plant Factories

Here are three reasons why lettuce is suitable for plant factories.

Reason 1

First, the short cultivation period.

Lettuce is a fast-growing vegetable that takes about 30 days from sowing to harvesting, resulting in a high turnover rate.

This isn’t limited to plant factories, but it’s crucial to maintain a high operating rate in facilities with significant capital investments like factories.
It would be a waste to invest a lot and not use it.

In this regard, lettuce’s short cultivation cycle is a significant advantage.
It allows for flexible production based on demand.

Reason 2

The second reason is that lettuce has a compact shape.

This allows for the effective use of limited cultivation space.

Lettuce doesn’t have an elongated stem, and its leaves spread out horizontally from the base in a rosette shape.
In other words, it has a low height and can be cultivated with narrow spacing.

It’s a perfect match for vertical cultivation using multi-tiered shelves.

Reason 3

The third reason is that lettuce is traded at a relatively high unit price.

However, this is only slightly higher than general field-grown lettuce and not significantly high-priced.

Even so, combined with the high turnover rate, a unit price that can cover the production costs in plant factories is achievable.

But you can actually grow other vegetables besides lettuce, right?

I’ve been talking about why lettuce is suitable for plant factories.

But in reality, you can grow other vegetables in plant factories.

Other leafy greens, of course, and even fruiting vegetables can be cultivated.

However, because lettuce is a miracle fit for the characteristics of plant factories, there’s no point in growing other vegetables.

Lettuce has a decent market demand, and it’s just a “make as much as you can!” situation.

As a result, naturally, other vegetables are less likely to be selected at the “which vegetable should we grow?” stage.

That’s how plant factories have become filled with lettuce before anyone knew it.

Lettuce is Easy to Grow

Also, in my opinion, lettuce crop management is relatively easy.

You can grow it without a lot of deep knowledge, and there’s little variation in growth.
Even if you neglect temperature control or the nutrient solution concentration is inappropriate, it’s unlikely to result in a devastating crop failure.

Of course, detailed management and the accumulation of know-how are essential to maximize growth and produce high-quality lettuce. To improve production efficiency, knowledge in areas other than plant physiology is also necessary.

Still, compared to other crops, it’s a beginner-friendly vegetable.

Even if a company newly enters the industry from a different sector, lettuce cultivation is easy to get started with.
Once the equipment is in place, products can be shipped relatively quickly.

Perhaps these circumstances also contribute to the fact that lettuce has become the main crop in plant factories.

Many companies entering the plant factory industry are from different sectors. Vegetables that are difficult to grow are less likely to be selected.

Oh, and by the way, my website provides know-how to maximize the profitability of plant factories.
Based on my experience, I’ve spent a lot of time refining the content, so I think it will be useful in any workplace.

Breaking Away from Lettuce Dependence

The situation where lettuce is the mainstream crop in plant factories will likely continue in the future.

However, there’s a sense of concern on the ground.

I often get asked by people on the ground,
“Are there any good vegetables?”

If there’s too much plant factory-grown lettuce, the market will become oversupplied.
Also, further business expansion will be difficult with only lettuce.

However, improving cultivation technology and developing sales channels are essential for introducing new crops.

Other crops may not be as easy to grow as lettuce, and the demand outlook is uncertain.
The barriers to entry will be higher, but that’s why higher added value can be expected.

As I wrote in the following article, strawberry plant factories have been appearing recently.

Wasabi is also attracting attention.

What are the Conditions for Vegetables Suitable for Plant Factories?

So, once again, what are the conditions for vegetables suitable for plant factories?

Based on the lettuce case, the following points are considered important:

Lettuce’s strength is that it clears these conditions at a high level.

If you are looking for new crops, how well these conditions can be met will be an important criterion.

Towards the Development of Plant Factories

Plant factories are still under development.

With the increase in participating companies, production capacity is increasing, but recently, there is a bit of overcompetition.
Differentiation will inevitably be essential in the future.

The introduction of new crops can be a trump card.

Somehow, we want a new standard product unique to plant factories.
This will avoid competition with mere commodities and make it possible to develop niche markets with large profit margins.

However, even in that case, it is important to select items that take into account the characteristics of plant factories.

Even if it is not as high as lettuce, a certain level of turnover and a sufficient unit price are required.
If this point is misjudged, there is a risk that high investment costs cannot be recovered.

What are the characteristics of lettuce in plant factories?

• Short cultivation period (about 30 days from sowing to harvesting)
• Compact shape that allows for the efficient use of cultivation space
• Traded at a relatively high price

What are the challenges of plant factories?

• Lettuce dependency and declining pricing power due to oversupply
• High initial investment and running costs
• Difficulties in acquiring cultivation techniques and developing sales channels for new items

Why is lettuce grown in plant factories?

• Short cultivation period with high turnover rate
• Compact plant shape allows for efficient use of cultivation space
• Relatively high selling price offers the prospect of profitability