Canola Growing Degree Days and Water Requirements: A 2026 Season Guide
Canola is the crop on every active OCM Agrisystems monitoring site this season, planted in mid-May 2026. That makes it a good moment to walk through how growing degree days and water balance data apply specifically to a canola crop across a typical season.
Canola’s base temperature
Growing degree day calculations start with a base temperature, the point below which a crop does not accumulate meaningful growth. Canola’s base temperature sits at around 5°C, similar to other cool-season broadleaf crops and lower than the base used for grapevines. Every degree above that threshold on a given day counts toward the season’s GDD total.
Tracking growth stages through the season
A canola crop moves through a series of recognisable stages after emergence: the rosette stage, stem elongation or bolting, flowering, pod development and finally maturity. Calendar days alone are a rough guide to when these stages will arrive, because a warm week pushes a crop forward faster than a cool one.
Accumulated GDD is a more reliable way to anticipate timing, because it reflects the heat the crop has actually received rather than the number of days that have passed. Tracking GDD per site lets growers compare how a season is tracking against what they would normally expect, and adjust plans for fungicide timing, desiccation and harvest logistics accordingly.
Water requirements shift through the season
Canola does not draw on soil moisture at a constant rate across the season. Water demand rises through stem elongation and typically peaks around flowering and early pod fill, which is also when the crop is most sensitive to moisture stress. A shortfall during this window has a bigger impact on yield than the same shortfall earlier or later in the season.
This is where water balance tracking earns its keep. Comparing rainfall against reference evapotranspiration, calculated using the FAO-56 method, shows whether a site is gaining or losing soil moisture week to week, rather than leaving growers to guess from rainfall totals alone.
Tracking canola specifically on the OCM dashboard
Because planting dates are recorded per site, GDD accumulation for a canola crop is charted from its own emergence date rather than a generic season start. The water balance chart runs alongside it, plotting rainfall against ET0 for the same period.
For growers monitoring more than one canola site, or comparing this season against a previous one, the Compare Sites tool overlays the same parameters across multiple sites and seasons, making it easier to see which properties are tracking ahead or behind.
The bottom line
Canola rewards growers who track heat accumulation and soil moisture closely, since both flowering and pod fill are narrow windows where the wrong conditions cost yield. The OCM Agrisystems cloud dashboard tracks growing degree days and water balance for every canola site automatically, so the numbers are there when a timing decision needs to be made.
Frequently Asked Questions:
What base temperature is used for canola GDD calculations?
OCM Agrisystems uses a base temperature of around 5°C for canola, consistent with common agronomic references for the crop.
Does the water balance chart include irrigation?
The water balance chart tracks rainfall against reference evapotranspiration for the site. It gives a season-long picture of moisture trends and works alongside the direct soil moisture readings from OCM’s probes, rather than replacing them.
Can I compare this season’s canola crop to a previous season?
Yes. The Compare Sites tool can chart current and historical sites side by side across the same parameters, including GDD accumulation and water balance.