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Tipburn Complete Guide! Unexpected Causes and Fundamental Solutions

Hello everyone! I’m Shohei.

If you’re cultivating leafy vegetables, you’ve probably seen tipburn.

This tipburn…

It’s commonly seen in leafy vegetables such as lettuce, and its occurrence leads to a decline in product value and reduced profits.

It is the greatest enemy for plant factories and cannot be avoided.

Tipburn just won’t go away…

I’m sure there are many people lamenting that.

I’ve been plagued by it for many years as well…

For producers, dealing with tipburn is an urgent issue.

However, after talking to various people, I realize that surprisingly many people don’t know the essential causes and solutions.

So, in this article, I’ll delve into the causes of tipburn and explain fundamental solutions in an easy-to-understand way, based on my own experience.

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What is Tipburn?: Occurs on the Leaves of Lettuce, Strawberries, etc.

Tipburn is a physiological disorder where the tips of leaves discolor and appear withered.

To put it roughly, the cause is a calcium deficiency in the leaves. It’s commonly seen in lettuce, strawberries, herbs, and leafy vegetables cultivated in plant factories.

However, please be careful!

The direct cause is calcium deficiency, but there are many reasons why this happens. Sometimes there are unexpected reasons.

In other words, simply increasing the calcium in the nutrient solution won’t eliminate tipburn just because there’s a calcium deficiency.

Some people misunderstand this, so please be careful.

Understand it properly and take fundamental measures.

Causes of Tipburn – Plant Factories are Prone to It

Before talking about solutions, let’s talk about the causes.

The direct cause of tipburn is a lack of calcium in the plant (specific parts).

It’s also a fact that plant factories are particularly prone to it, so I’ll explain that as well.

The secret lies in the cultivation environment unique to plant factories and the movement of water and calcium within the plant.

Mechanism of Tipburn Occurrence Explained at the Cellular Level!

Plant cells are surrounded by a strong wall called the cell wall. The role of the cell wall is to maintain the shape of the cell and protect it from external stress.

Calcium has the function of strengthening pectin, which is a component of this cell wall.

If calcium is deficient, the cell wall weakens.
Therefore, it cannot withstand the pressure inside the cell (turgor pressure).

As a result,

Cell wall destruction ▶ Tipburn occurrence

That’s the flow.

Young leaves and the tips of leaves especially need a lot of calcium.
This is because cell division is active and cell walls are being made one after another.

Calcium deficiency is likely to occur in these parts, and tipburn is likely to occur.

The sight of a large amount of tipburn in the middle of lettuce is something you’ve seen at least once if you’ve worked in a plant factory.

Yeah, it’s sad every time I see it…

Relationship with High-Speed Cultivation

But why only plant factories…

Well, tipburn can occur even outside of plant factories, to be precise. However, it is especially prone to occur in plant factories.

Why?

That’s because plant factories use “high-speed cultivation” to accelerate plant growth by controlling light, temperature, humidity, CO2 concentration, etc.

This high-speed cultivation is one of the factors that increase the risk of tipburn.

Plants use the energy obtained from photosynthesis to grow. The growth rate of plants is accelerated by promoting photosynthesis.

However, naturally, the amount of nutrients required for growth also increases.

Some nutrients cannot keep up with the supply to the leaves.
The most prominent of these is calcium.

In addition, vertical cultivation unique to plant factories and dense planting to increase production efficiency also increase the risk of tipburn.

Factors that Cause Calcium Deficiency in Leaves

And here’s where the difficulty of tipburn lies.

That is, there are several possible factors that can cause calcium deficiency.

For example, like this:

  • Ammoniacal Nitrogen Concentration in Nutrient Solution:
    • When a large amount of ammoniacal nitrogen is absorbed, the inside of the plant becomes acidic, which inhibits calcium absorption.
  • Potassium and Magnesium Concentration in Nutrient Solution:
    • Potassium and magnesium are absorbed by plants in the same way as calcium, so if their concentration is high, calcium absorption is competitively inhibited.
  • Root Activity:
    • If root development is insufficient or root activity is low, calcium absorption efficiency decreases.
  • Humidity:
    • If humidity is high, transpiration is suppressed, and the amount of calcium supplied to the leaves decreases.

In addition, there are structural problems at the site, days to harvest, and so on. The possibilities are truly endless.

However, in the end, even if you absorb a lot of calcium, you can’t keep up if the growth rate is too fast.

So, how should we deal with tipburn? Let’s take solid fundamental measures.

Fundamental Measures Against Tipburn – 3 Approaches

First, one premise for tipburn measures.
That is, the places where it is likely to occur are fixed.

Specifically,

  • Times when it is likely to occur:
    • Rapid growth period before harvesting
  • Places where it is likely to occur:
    • Newly developed leaves, especially inner leaves surrounded by outer leaves

In other words, it only occurs in the period before harvesting when it is getting bigger.

That means the measures should be tailored to that as well.

Environmental Control

  • Humidity Management:
    • If the humidity is excessively high, use a dehumidifier to maintain appropriate humidity.
    • Appropriate humidity varies depending on the type of plant and growth stage, but it is generally around 60-70%.
  • Temperature Management:
    • Perform appropriate temperature management. In the case of leafy vegetables such as lettuce, the optimum growth temperature is around 20-25°C.
  • Wind:
    • By sending a gentle breeze and lowering the humidity around the leaves, transpiration is promoted, and calcium transport is promoted. However, be careful as too strong a wind can stress the plants.

Nutrient Management

  • pH Adjustment of Nutrient Solution:
    • Calcium is most easily absorbed in the pH range of 5.5-6.5.
  • Use of Nitrate Nitrogen Fertilizer:
    • Nitrate nitrogen fertilizer has the effect of making the pH in the plant alkaline, which promotes calcium absorption.

Optimization of Cultivation Process

  • Appropriate Planting Density:
    • If the planting density is too high, the base of the plant becomes excessively moist, and transpiration does not proceed.
    • It is important to maintain an appropriate planting density to improve ventilation and promote transpiration.
  • Variety Selection:
    • Selecting varieties that are resistant to tipburn is also effective.

The Important Thing is From Here

Now, I’ve written about relatively common tipburn measures.

It seems easy when written like this, doesn’t it?

But, I’ll write the most important thing.

That is,
Taking measures against tipburn tends to lower productivity because you have to abandon “high-speed cultivation.”

Wait a minute.
If you slow down the growth rate, you can’t earn money.

Yes, that’s right. That’s the difficult part.

In other words, you have to achieve the highest yield while dealing with tipburn.

This is where the crop management staff can show their skills.

You must deeply understand plant physiology and environmental control and improve them appropriately.

There are Techniques to Balance Tipburn Measures and Productivity.

Currently, many plant factories are suffering from tipburn.
Many plant factories have already taken the measures mentioned above.

So, why doesn’t tipburn disappear?

In reality, there are several techniques to increase productivity while taking tipburn measures.
Environmental control, cultivation process ingenuity, and on-site operation improvements.

In some cases, dramatic changes occur with unexpected improvements.

Such techniques are written quite a bit in the following content on our site.
Please see the following as well.

It’s a bit expensive, but considering the improvement effect of the know-how you can get by reading it,
I think the cost-effectiveness is high.

Summary | Overcome Tipburn and Produce High-Quality Vegetables!

Tipburn is one of the serious problems in plant factories, but
You can prevent it if you understand the causes and solutions correctly.

Refer to the contents introduced in this article, suppress the occurrence of tipburn, and strive to stably produce high-quality vegetables!

Bonus. What is the Impact of Tipburn?

Finally, my opinion after facing lettuce cultivation in plant factories for many years.

In reality, you may still be able to sell even if tipburn appears.
Because it’s not inedible.

However, the appearance is very bad.

There is a reality that “vegetables are chosen by appearance,” and it is certainly not a good situation.

In the end, if tipburn appears,
Considering the risk of losing the trust of customers, you will not ship it, or you will remove only the tipburn part and ship it.

However, there are also sites that are desperately removing even small tipburn.
Is it really necessary to do that much?

If you tear off the leaves recklessly, there is a risk that rot will progress from that leaf,
Considering comprehensively, isn’t the disadvantage greater if you remove tipburn?

Don’t worry too much about tipburn,
Let’s identify the level where there is a problem and deal with it.

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