About Greenhouse Growing Season

Building

• The greenhouse building must be equipped with proper heating, watering and ventilation systems if it is to be productive year-round, especially in areas with cold and snowy winters. To grow plants in a greenhouse, grow lights may be required for plants to make up for shorter days with less sunlight, and more heat will be necessary to keep the greenhouse at a stable temperature. Consistent watering of the plants is also important for growth.

Pests

• Although pests are less likely to appear in winter, they can thrive in the warm, contained environment of a greenhouse. Check plants for pests throughout the growing season and keep pesticides on hand in case they become necessary. An outbreak of mites, aphids or another type of pest insect can severely damage a crop and end the greenhouse growing season prematurely.

Preparation

• In order to ensure a successful growing season throughout the winter, the greenhouse should be cleaned thoroughly in the fall and in the spring. Remove all tables, plants and items that can be taken outside and clean the windows, floors and walls with a garden disinfectant to kill any mold and mildew. These fungi thrive in warm environments, and can cause health problems and plant damage, especially during the winter.

Plant Types

• According to the Washington State University Cooperative Extension, growing cold-tolerant plants in the winter can be more profitable. The greenhouse can be kept slightly cooler, which reduces heating costs. Plants like lettuce, chard, spinach and turnips can be grown throughout the year and produce profitably in a greenhouse. With extra heat and lighting, plants like melons and tomatoes can bear fruit; however, their yields are often lower and of a lesser quality.

Considerations

• The greenhouse season alters with the regular seasons, despite the farmer's ability to grow plants year-round. Changing the focus of the growing as the seasons change enables farmers to produce profitable vegetables by focusing on the plants that will grow the best during the off-season. Clean the greenhouse properly in between planting seasons so that any pests, mold and mildew present are removed and do not cause damage later on during the growing season.