Greenhouse cannabis: navigating power costs and grid reliability

Your lighting strategy has become a critical business decision that connects plant biology with power management, especially as South Africa's electricity landscape continues to evolve

- Thomas Walker

Running a successful greenhouse cannabis operation today means thinking beyond just which lights to buy. Eskom has been delivering more stable power, with improved energy availability across their coal-fired stations. But let's be realistic: the utility is still managing tight periods with emergency reserves, so smart growers are planning for variability while making the most of this new stability.

Here's what's shaping every lighting decision. First, electricity bills got heavier. Eskom’s direct customer tariffs jumped 12,74% from April 2025, and that’s money straight out of your margins. Second, if you're on a time-of-use tariff, and most commercial growers are, you're paying drastically different rates depending when you flip those switches. Ignore these peak and off-peak windows, and you'll watch your profits evaporate.

The smart play? Schedule your supplemental lighting during off-peak hours wherever possible, and invest in control systems that target a daily light integral (DLI) instead of just running lights for fixed hours. This approach can genuinely cut your cost per gram.

DAILY LIGHT INTEGRAL