How to Grow Tomatoes in a Greenhouse

Tomatoes, with their juicy, sun-kissed goodness, are a garden favourite. But what if you could elevate your tomato-growing game to a whole new level of deliciousness? Enter the greenhouse.

This guide will walk you through the secrets of growing this red fruit and vegetable. Not in an open backyard, though, but in an enclosed structure. The controlled oasis this growhouse provides will have you reaping tomatoes year-round. Let’s dig in!

Step 1: Selecting the right garden greenhouse

BillyOh 4000 Lincoln Wooden Clear Wall Greenhouse with Roof Vent
BillyOh 4000 Lincoln Wooden Clear Wall Greenhouse with Roof Vent

Choosing the right type and size of greenhouse is key to your tomato journey. Location matters also matter. Ensure the structure receives ample sunlight and is sheltered from harsh winds.

The choice of materials affects insulation and durability. Common options in the market include:

  • Wooden greenhouses top the list thanks to their natural thermal properties. The only downside is the maintenance they require to combat rot and pests.
  • Polycarbonate greenhouses, in contrast, provide superb insulation by trapping air between layers. Their twin-wall panels also enhance durability, making them resistant to weather damage.
  • Finally, metal greenhouses, such as aluminium, are durable but tend to conduct heat. Yet, they tend to demand additional insulation. Overall, they can withstand harsh conditions while providing a long-lasting structure.

Additionally, ventilation is crucial to prevent overheating. A well-suited greenhouse maximises growing space and optimises environmental control. These factors are what guarantee your tomatoes thrive.

Step 2: Preparing the structure

BillyOh Harvester Walk-In Aluminium Polycarbonate Greenhouse
BillyOh Harvester Walk-In Aluminium Polycarbonate Greenhouse

Cleaning and sanitising the growhouse is essential for creating a healthy growing environment. Over time, debris and pathogens can accumulate, potentially harming your tomato plants. Regular cleaning removes dirt, pests, and diseases, reducing the risk of contamination. Sanitising helps eliminate lingering pathogens, preventing disease outbreaks. This practice sets the stage for vigorous tomato growth.

Proper soil preparation and container selection are equally vital. Well-prepared soil ensures that your tomatoes receive essential nutrients and good drainage. Containers should accommodate your chosen tomato varieties. Moreover, ensure they allow for root development and prevent overcrowding.

Step 3: Choosing tomato varieties

Red tomatoes

(Image Credit: Flickr)

Selecting tomato varieties tailored for greenhouse growth is crucial. These varieties are bred to thrive in the controlled environment of a greenhouse. They often exhibit characteristics such as:

  • disease resistance
  • compact growth habits
  • fruit that sets well in these conditions

Recommended varieties include ‘Early Girl,’ ‘Sungold,’ ‘Celebrity,’ and ‘Big Beef.’ By choosing the right tomato, you’ll set yourself up for a successful greenhouse harvest.

Step 4: Planting tomatoes

Greenhouse tomatoes

(Image Credit: Flickr)

When planting tomato seeds, adhere to best practices for optimal growth. Begin by ensuring proper spacing between plants, typically about 18-24 inches apart. This method ensures healthy air circulation and prevents overcrowding.

Plant seedlings at an appropriate depth. Bury them about 1/4 to 1/2 inch deep in well-prepared, nutrient-rich soil. Maintain consistent moisture levels and provide adequate support as they grow.

Step 5: Providing ideal conditions

Red tomato plants planted in a greenhouse

(Image Credit: PickPik)

Tomatoes in a walk-in greenhouse require precise environmental control. Maintain temperatures between 70-75°F (21-24°C) during the day and slightly lower at night. Ensure humidity levels are around 60-70% for optimal growth. Adequate lighting promotes photosynthesis. Preferably with 12-16 hours of sunlight or supplemental high-quality artificial lighting

Regular monitoring of temperature, humidity, and light levels is vital. Be prepared to make adjustments as needed. Use fans, vents, shade cloth, and heaters to maintain ideal conditions. This vigilance ensures your greenhouse tomatoes flourish in a carefully controlled microclimate.

Step 7: Pruning and training

Greenhouse staff harvesting tomatoes

(Image Credit: Flickr)

Pruning and training tomato plants in a greenhouse offers several benefits. They encourage better air circulation, reducing the risk of diseases. Pruned and trained plants also allocate more energy to fruit production. This, in return, results in larger and more abundant tomatoes.

To do this in a greenhouse, use stakes or trellis arches to support the plants. What’s more, regularly remove side shoots and lower leaves. Maintain a single or double stem system to maximise space and light utilisation.

Step 8: Pest and disease management

Hobby greenhouse tomatoes are susceptible to pests like aphids, whiteflies, and spider mites. Also, diseases including powdery mildew and botrytis. Organic control methods involve introducing beneficial insects. Take ladybugs, for instance, and use neem oil or insecticidal soaps.

Chemical options include pesticides and fungicides. But take note that their use should be judicious and follow safety guidelines. Regular monitoring, proper sanitation, and a balanced growing environment are key.

Step 9: Harvesting and storage

Tomatoes harvested at a greenhouse

(Image Credit: Flickr)

The right time to harvest tomatoes is when they reach full colour and firmness. Typically, when they are fully ripe or slightly underripe.

Gently twist or cut the fruit from the vine, leaving a small stem attached. Be careful not to bruise or damage the tomatoes during harvesting. After harvest, store tomatoes at room temperature or in a cool, dark place to ripen further. Avoid refrigeration, as it can affect the flavour and texture.

Enjoy your freshly harvested greenhouse tomatoes at their peak!

If you haven’t found the ideal growing sanctuary yet, Garden Buildings Direct has you covered! In addition to greenhouses, we also offer a wooden growhouse and potting shed.

Next on your reading list: 5 Best Plants To Grow In Your Greenhouse