Crop steering is an irrigation and climate strategy, developed in greenhouse tomato and adopted widely in commercial cannabis, that uses the plant's root-zone water status as a lever. Vegetative steering keeps the substrate wetter, with smaller drybacks and frequent small irrigations, to encourage leaf and stem growth. Generative steering uses larger drybacks, higher substrate EC and fewer, later irrigations to push flower development.
In practice
Growers measure substrate water content and EC with sensors or by weighing a pot, set a first irrigation time after lights-on, deliver small "shots" until the medium is near container capacity, then let it dry back overnight by a target percentage. Typical guides quote overnight drybacks of a few percent for vegetative steering and larger ones for generative, but numbers depend on the substrate and sensorbeing reviewed. It works best in rockwool and coco, which have fast, predictable water dynamics.
Evidence: grower and industry practice, with limited peer-reviewed cannabis trials.
Don't confuse with
- Drought stress: an uncontrolled or extended dry-down; steering is precise and daily.
- Training: physical shaping; steering is irrigation-based.
Dryback is the drop in a substrate's water content between irrigations, usually expressed as a percentage of its content at full saturation.EC (electrical conductivity) measures how well a solution conducts electricity, a proxy for total dissolved salts; growers read it in mS/cm to gauge nutrient strength.The amount of water in a material as a percentage of its weight; cured cannabis flower usually sits around 10-12% w/w, though measurement method matters.Field capacity is the amount of water a medium holds after it has been saturated and allowed to drain freely; in pots it is called container capacity.Rockwool is an inert growing medium spun from melted basalt rock into fibres, sold as plugs, cubes and slabs, that holds water and air in fixed proportions.Coco coir is a growing medium made from processed coconut husk, prized for holding water and air at once; it binds calcium and magnesium unless buffered.Drain-to-waste fertigation feeds each plant fresh nutrient solution and lets the runoff leave the system rather than returning it to the reservoir.High-frequency fertigation feeds small volumes of nutrient solution many times a day, keeping the root zone consistently moist and fed so small pots can produce large plants.
