Interactions between irrigation method and liquid feed in bedding crops

What factors need to be considered in your irrigation/feed set-up?

Overhead irrigation

• Liquid feed via overhead irrigation can be as effective as doubling the feed concentration delivered by other methods of irrigation.
• Frequent, smaller doses of overhead irrigation can deliver lower concentrations of feed most effectively.
• The electrical conductivity of growing media may appear low in comparison to feed delivered by other irrigation methods, so monitor plants for deficiency before increasing feed amount.
• Overhead irrigation delivery of liquid feed can give more consistent results than feed delivered by other irrigation methods.
• If water use is low, the feed amount can be increased by altering feed/water ratios.
• In hard water areas the pH of growing media increases more when using overhead irrigation than with either capillary matting or ebb and flow.

Capillary matting with irrigation

• Capillary matting retains water and can lead to lower water use and lower feed availability.
• If water use is low, the feed amount can be increased by altering feed/water ratios.
• If feed/water ratio is increased, monitoring of growing media EC is important as capillary matting can build up excess nutrients.
• Nutrient toxicity can happen if EC is high leading to poor quality, stunted plants.

Nutrient toxicity in pansy

Ebb and flow irrigation

• Plants grown with ebb and flow irrigation can grow bigger than with other irrigation methods.
• The EC of the growing media stays higher than with overhead irrigation.
• If water use is low, the feed amount can be increased by altering feed/water ratios.