How To Grow Tomatoes In A Greenhouse

Growing tomatoes in a polycarbonate greenhouse the secrets of planting
Growing tomatoes in a polycarbonate greenhouse the secrets of planting from

Tomatoes are one of the most popular and widely grown vegetables in home gardens and commercial farms. While they can be grown outdoors, growing tomatoes in a greenhouse offers numerous advantages. Greenhouses provide a controlled environment that allows for year-round tomato cultivation, protection from pests and diseases, and the ability to optimize growing conditions. In this article, we will explore the key steps and considerations for successfully growing tomatoes in a greenhouse.

1. Choosing the Right Tomato Varieties

When selecting tomato varieties for greenhouse cultivation, it is important to consider their growth habits, disease resistance, and suitability for greenhouse conditions. Determinate varieties, which have a compact growth habit and produce a single crop, are often preferred for greenhouse cultivation due to their manageable size and ease of support. Some popular greenhouse tomato varieties include ‘Celebrity’, ‘Mountain Fresh’, and ‘Sun Gold’.

2. Providing Optimal Growing Conditions

To ensure healthy growth and maximum yield, tomatoes require specific growing conditions. In a greenhouse, you have control over these conditions, allowing you to provide the ideal environment for your plants. Here are some key factors to consider:

  • Temperature: Tomatoes thrive in temperatures between 70-85°F (21-29°C) during the day and 60-70°F (15-21°C) at night. Use a thermometer to monitor and maintain the temperature within this range.
  • Light: Tomatoes need at least 8-10 hours of direct sunlight or high-quality artificial light each day. Supplemental lighting may be required during the winter months or in areas with limited sunlight.
  • Humidity: Maintaining a humidity level of 50-70% is ideal for tomato plants. Good ventilation and air circulation are essential to prevent the development of fungal diseases.
  • Air Quality: Carbon dioxide (CO2) enrichment can significantly boost tomato growth and yield in a greenhouse. Providing proper ventilation and periodically introducing CO2 can help improve air quality.

3. Preparing the Soil

Tomatoes require well-drained soil with good fertility and a pH level between 6.0 and 6.8. Before planting, prepare the soil by:

  • Amending the Soil: Add organic matter, such as compost or well-rotted manure, to improve soil structure and fertility.
  • Adjusting pH: Test the soil pH using a kit and adjust it if necessary by adding lime to raise pH or sulfur to lower pH.
  • Providing Nutrients: Incorporate a balanced fertilizer into the soil to ensure adequate nutrient availability for the plants.

4. Planting and Supporting Tomato Plants

When planting tomatoes in a greenhouse, follow these steps:

  • Start with Healthy Seedlings: Use high-quality tomato seedlings or start your own from seeds 6-8 weeks before the intended planting date.
  • Spacing: Allow 18-24 inches (45-60 cm) between plants to ensure adequate air circulation and sunlight penetration.
  • Support: Install trellises, stakes, or cages to support the tomato plants as they grow. This will help prevent the plants from sprawling and keep the fruit off the ground.
  • Watering: Water the plants regularly, keeping the soil consistently moist but not waterlogged. Avoid wetting the foliage, as this can promote disease development.

5. Pruning and Training

Proper pruning and training are crucial for tomato plants in a greenhouse to promote healthy growth and maximize yield. Follow these guidelines:

  • Remove Suckers: Suckers are the small shoots that emerge from the leaf axils. Pinch them off to direct the plant’s energy towards fruit production.
  • Prune Lower Leaves: Remove the lower leaves of the plant to improve air circulation and reduce the risk of soil-borne diseases.
  • Train the Main Stem: Attach the main stem to the support structure and gently guide it as it grows. This will help maintain an upright habit and prevent breakage.

6. Pest and Disease Management

In a greenhouse environment, pests and diseases can still pose a threat to tomato plants. Implement the following measures to prevent and manage common issues:

  • Monitor Regularly: Inspect plants frequently for signs of pests or diseases, such as aphids, whiteflies, or powdery mildew.
  • Biological Control: Introduce beneficial insects, like ladybugs or predatory mites, to control pests naturally.
  • Sanitation: Keep the greenhouse clean and remove any fallen leaves or plant debris to reduce disease pressure.
  • Organic Sprays: If necessary, use organic insecticides or fungicides as a last resort, following label instructions carefully.


Growing tomatoes in a greenhouse can be a rewarding and successful endeavor. By choosing the right tomato varieties, providing optimal growing conditions, preparing the soil, planting and supporting the plants properly, pruning and training, and managing pests and diseases effectively, you can enjoy a bountiful harvest of delicious tomatoes throughout the year. With careful attention to detail and regular maintenance, your greenhouse can become a thriving tomato paradise.

Leave a Reply

Your email address will not be published. Required fields are marked *