Tomato production as it it’s best when daytime temperatures are between 18°C to 29°C, and as those living in Australia will know summer heatwaves can deliver days on end of temperatures over 35°C and fruit set will be impacted.
The solution is to reduce the stress on the tomato plants by providing shade during the hottest months of January and February. Using a lightweight, white, UV stabilised shadecloth allows sufficient sunlight for growth while assisting with water saving, reducing evaporation and providing protection from wind.
Increased yields may result from shading Tomatoes, as you will be reducing the stress on the plant – and flowering, pollination, and fruit set can continue.
A 50% white shadecloth is commonly used in commercial greenhouse production, usually placed inside the structure underneath the ceiling as a retractable curtain that can play an important role for managing temperature. It is important to note that the 50% refers to the reduction in light, the reduction in actual temperature is about half that – so you will get a 25% reduction in heat.
The types of fabric used are either knitted or woven. Woven is constructed from woven polypropylene. It is about 30% heavier than knitted and typically costs more. The lifespan is about 10-12 years. Woven is more plastic looking than knitted and has a distinct grid of horizontal and vertical lines. Woven cloth is only available in black.
Knitted shadecloth is made from knitted polyethylene and has an expected life of 7-10 years. More cloth-like to the look and feel and has threads running in various directions. Due to the construction, it will not unravel if cut or if a hole occurs and it is available in various colours.
50% white shadecloth is ideal for placing over your vegetable garden in January and February to protect the tomatoes from the summer heat. Heat stress forces a plant to increase transpiration to survive, and will impact plant health and fruit set if the heat continues for prolonged periods.
Building a structure to support your shadecloth can be simple or complicated – Adelaide’s local radio gardening program on 891 recently featured shade structures for tomatoes – read more and view photos here.