When to Plant Tomatoes in Unheated Greenhouse NZ

Growing tomatoes in an unheated greenhouse in New Zealand comes with many benefits. One of the biggest advantages is the ability to extend the growing season and start planting crops earlier in the year. However, it is important to know when to plant your tomatoes to maximize your yield and avoid potential problems.

Climate Considerations

New Zealand has a diverse climate that varies depending on your location. The climate plays a critical role in determining when to plant tomatoes in an unheated greenhouse. Some areas in the country experience milder winters and warmer temperatures, while others face colder conditions.

If you are living in a region with harsh winters, it is best to wait until spring before planting your tomatoes. In places like the South Island, it is not recommended to plant tomatoes until November as the temperatures are too low. However, areas such as the Northland experience milder winters, making it possible to start planting as early as August.

Seedlings vs. Seeds

Tomatoes can be grown from seeds or purchased as seedlings from a garden center. Choosing between planting seeds or seedlings is important when deciding when to plant tomatoes in an unheated greenhouse.

If you plan to grow from seeds, you'll need to start them indoors (or under cover) approximately six weeks before the expected planting date. This will give them enough time to mature before planting outdoors in the unheated greenhouse. However, if you purchase seedlings, you can plant them directly into the soil in your unheated greenhouse as soon as outdoor temperatures allow.

Soil Temperature and Preparation

The soil temperature is crucial when it comes to planting tomatoes in an unheated greenhouse. Tomatoes thrive in warm soil, so it is important to ensure that the temperature is adequate before planting.

The ideal soil temperature for planting tomatoes is between 18-24°C. This means that the soil should be warm enough to allow for healthy growth but not too warm that it causes problems. To prepare the soil, ensure that it is well-draining and has adequate moisture. The soil should also be enriched with compost or other organic matter to provide nutrients for the tomato plants.

Frost Protection Measures

While unheated greenhouses offer many benefits, they also come with some risks. Frost is one of the biggest concerns for growers as it can damage and even kill tomato plants. To protect your plants from frost, it is important to take preventative measures.

You can install frost cloth, which is a lightweight fabric that provides protection from cold temperatures. Additionally, you can use cloches, which are individual plant covers that provide insulation for each plant. Be sure to remove any frost protection measures during the day when the sun is out to avoid overheating.

In Conclusion

When to plant tomatoes in an unheated greenhouse in New Zealand can vary depending on several factors such as the climate, whether you are planting seeds or seedlings, the soil temperature and preparation, and frost protection measures. By taking these factors into consideration, you can ensure healthy plant growth and a bountiful harvest of delicious tomatoes.