Summer has finally arrived on the West Coast. The cucumbers in the greenhouse are behind because of the cool wet weather. Now my goal will be to control the hot greenhouse environment. Fluctuating temperature is often the major cause of plant and crop damage.
Ventilation and air circulation is a priority. Greenhouse vents and louvres will be wide open and circulating fans are set at high speed. An exhaust fan system in one of my greenhouses works very well to control the greenhouse temperature. This greenhouse is in a sunny location and the cacti and orchids are there for the summer months. With the prediction of a hot July, I will have to consider attaching a shade cloth to the outside of my glass greenhouse. Shade cloth fasted to the outside of the greenhouse prevents the heat from building up inside. For further information regarding shade cloth and exhaust fan ventilation packages visit the B.C. Greenhouse Builders website www.bcgreenhouses.com
Increasing humidity will cool the atmosphere and bring down the temperature in the summer greenhouses. To keep moisture and humidity in the air I always have some watering cans filled in the summer season. Concrete floors and benches will also take moisture out of the air. I hose down the floor and benches on hot days. This action is called “damping down” and you can feel the humidity rise.
Plants will require more frequent watering sometimes twice a day depending on the weather and the plants. Greenhouse tomatoes and cucumbers will suffer if they are not watered daily during the summer months. My cucumbers are in a self-watering grow box but the tomatoes I watch closely. On a dull day, they may get a cup of water and sunny days may receive half a gallon of water twice a day. I start feeding tomatoes and cucumbers after flowering and the fruits are starting to form. A liquid tomato fertilizer high in phosphate and potash will encourage fruit formation.
Just a quick note: We have enjoyed another fresh salad. That was the third crop from the leaf lettuce plants. So successful I will seed another container of leaf lettuce for fresh salad crops in late summer early fall.