YOU WANT WET PLANTS, NOT SOAKED PLANTS
While these are all beneficial to plant growth, the downside of getting the process wrong can leave root zones
either desiccated between inadequate irrigations, or more
commonly, oversaturated, deoxygenated and prone to root
dieback and pythium attack. Unlike soil in a field situation, hydroponic systems have a highly restricted root zone
volume, which makes moisture and nutrient control and
supply far more critical for maximum growth.
Irrigation for the Right Substrate
Most hydroponic substrates are designed to hold a
certain amount of air and moisture between irrigations.
However, there are wide variations between different growing mediums with regard to these properties.
Luckily, substrates are usually selected based on their
suitability for different crops, climates and irrigation
systems. Porous and highly free-draining substrates such
as LECA (light expanded clay aggregates) chunky perlite,
various grow rocks and similar materials drain freely
and are highly aerated, but hold less moisture between
irrigations than many other mediums.
Fine-grade coconut fiber, peat, some grades of stone or
rockwool, vermiculite and organic mixes tend to have
a much higher water-holding capacity, giving a greater
degree of buffering capacity when it comes to root zone
moisture content, but are more prone to overwatering,
root suffocation and die back.
“
Irrigation schedules for different substrates
need to be matched to the properties of the
medium being used.”
Careful selection of emitters in drip systems helps ensure the correct
level of irrigation is maintained.
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Maximum Yield USA | October 2016