🍅 [For Professional Farmers] November Greenhouse Tomato Cultivation Management: The Key to Year-Round Success is 'Light' and 'Maintaining Vigor'

Hello. I am Takahiro Ogawa, an agricultural management supporter. Today, I will talk about the management points for tomato cultivation in November.

For tomatoes planted in late August, I trust you are entering the full-scale harvest season as we enter November. While you may feel encouraged by the daily yields, you cannot let your guard down during this period. This is because November is the final adjustment period to build up the plant's energy reserves for the harsh winter (January to February), when solar radiation is at its lowest for the year.

For those of you who have introduced environmental control systems, I will explain specifically 'what, why, and how' to manage cultivation in November. By thoroughly implementing this management, let's aim for stable yields and high-quality fruit production even in winter.

1. 🌡️ Bringing out the best performance! Precise environmental control techniques

November is the season when the true value of heating equipment and environmental control systems is tested. Here are some tips for temperature management to maximize tomato photosynthetic efficiency even under low solar radiation and low temperatures.

1-1. 'Proactive' early morning heating settings

Condensation and delayed photosynthesis due to low temperatures are the biggest causes of winter diseases and yield loss.

• Goal: Start heating about 2 hours before sunrise, and set it so that the temperature inside the greenhouse reaches 15°C to 16°C by sunrise.

• Control tip: Rapid temperature rise causes condensation. By programming the system to raise the temperature gradually at a pace of within 2°C per hour, you can reliably avoid condensation on the plant surface.

1-2. Day-night temperature difference and vigor adjustment

• Night temperature setting: To maintain vigor while promoting reproductive growth (fruit enlargement and coloring), set the night temperature to around 10°C to 12°C.

  • If you feel the current vigor is too strong, set the night temperature closer to 10°C; if it is too weak, raise it to 12°C to 15°C to maintain energy.

• Constant use of circulation fans: Temperature and humidity unevenness are breeding grounds for diseases (such as gray mold). Keep circulation fans running at all times to maintain uniform temperature and humidity inside the greenhouse.

1-3. Boosting photosynthesis with CO2 application

During periods of low solar radiation, CO2, the raw material for photosynthesis, tends to be insufficient.

• Application time: Actively apply CO2 to maintain a concentration of 800ppm to 1200ppm, if possible, during the morning (the time when photosynthesis is most active) from sunrise until the ventilation temperature is reached.

2. 💧 How to build 'roots' and 'stamina' that won't lose to the harsh winter: Water and fertilizer management

2-1. Irrigation management considering soil temperature

Irrigating with cold water weakens root activity and is a major cause of reduced vigor.

• Checking water temperature: If possible, ensure the irrigation water temperature does not drop below 15°C by mixing it with warm water or limiting irrigation to daytime hours.

• Method: The basic approach is 'small amounts, high frequency,' reducing the amount of irrigation per session while increasing the frequency. This prevents sudden fluctuations in soil moisture and suppresses the occurrence of fruit cracking.

2-2. Top-dressing strategy for maintaining tree vigor

November is the time for 'stockpiling' to prevent a sudden drop in tree vigor during the mid-winter period.

• Checkpoint: Check daily to see if the leaves near the growth point in the morning are pale green or if the stem diameter is becoming thin (be cautious if it is less than 10mm).

• Countermeasure: Use liquid fertilizer to provide a stable supply of top-dressing with a focus on phosphorus and potassium. If tree vigor is declining, supplement with foliar sprays of photosynthesis promoters or micronutrient fertilizers to achieve a quick recovery.

3. ✂️ 'Leaf pruning' and 'fruit thinning' for successful long-term harvesting

3-1. Leaf pruning with a balance of offense and defense

In winter, the role of each individual leaf becomes more significant. Careless leaf pruning leads directly to a decrease in photosynthetic capacity.

• Priority for leaf pruning: Remove in the order of diseased leaves > aging leaves > leaves that hinder fruit set, to ensure ventilation and light penetration.

• Goal: Leave about 15 to 18 expanded leaves, and be sure to always secure leaves that serve as the tree's source of stamina.

3-2. Thorough fruit thinning with an eye on mid-winter

From November onwards, a lack of solar radiation leads to insufficient translocation of photosynthetic products, making hollow fruit and poor coloring more likely to occur.

• Purpose: Limit the number of fruits to concentrate energy into each individual fruit, maintaining high-quality fruit enlargement even in winter.

• Practice: For upper flower clusters, limit the number of fruits set more conservatively than usual to ensure you can harvest high-quality fruit.

💡 Summary: The keywords for November are 'condensation prevention' and 'maintaining tree vigor'

By making the most of your installed environmental control equipment and thoroughly implementing 'early morning condensation prevention' and 'temperature and CO2 management to maximize solar radiation utilization,' you can get through this November and achieve stable harvests and high-quality tomato shipments even in mid-winter.

Let's aim for success in year-round cultivation with precise management based on daily data!

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