HPS in Winter, LED in Summer? Seasonal Grow Light Strategies

Many experienced growers have discovered that a seasonal approach to lighting can maximize efficiency and results. By leveraging the heat output of HPS lights in winter and the cooler operation of LEDs in summer, you can optimize your growing environment year-round.

The Seasonal Challenge

Indoor growers face opposite environmental challenges depending on the season:

"HPS in the winter and led any other time"

The Seasonal Lighting Strategy

Winter: Embracing HPS Heat

During colder months, the heat generated by HPS lights becomes an asset rather than a liability:

• Heating Benefit: HPS lights convert approximately 70% of their energy to heat, which warms your growing environment
• Reduced Heating Costs: Many growers report significant savings on heating bills
• Improved Humidity: The heat helps maintain better humidity levels in dry winter air
• Faster Metabolism: Warmer root zones promote better nutrient uptake

"I still use 600w HPS because it's cold and the heat is useful."

Summer: Switching to LED

As temperatures rise, the cooler operation of LED lights becomes advantageous:

• Reduced Heat Load: LEDs produce significantly less heat, making temperature management easier
• Lower Cooling Costs: Less need for air conditioning or extensive ventilation
• Reduced Water Usage: Plants typically require less frequent watering under LEDs
• Lower Electricity Bills: LEDs use less power during peak summer electricity rates

Cost-Benefit Analysis of Seasonal Switching

For many growers, the combined savings on heating in winter and cooling in summer can offset the cost of owning both lighting systems within 1-2 years.

Implementing a Seasonal Strategy

Option 1: Dual Lighting Systems

The most straightforward approach is to maintain both HPS and LED systems, switching between them seasonally:

• Install both lighting systems in your grow space
• Use HPS during colder months (typically October-March in Northern Hemisphere)
• Switch to LED during warmer months (typically April-September)
• Store the unused lighting system properly during off-seasons

Option 2: Hybrid Lighting

Some growers use both lighting types simultaneously, adjusting the ratio seasonally:

• Install both HPS and LED lights in your grow space
• Winter: Run primarily HPS with minimal LED supplementation
• Summer: Run primarily LED with minimal HPS (or none)
• Spring/Fall: Run a balanced combination based on temperatures

Option 3: Transitional Approach

For those who can't afford both systems immediately:

• Start with HPS if you're in a colder climate or LED if in a warmer climate
• Save the operational cost difference to invest in the complementary system
• Add the second system when budget allows
• Gradually transition to a seasonal strategy

Environmental Adjustments When Switching

When transitioning between lighting types, several growing parameters need adjustment:

Allow 7-10 days for plants to fully adjust to the new lighting type after switching.

Real-World Results

Growers who implement seasonal lighting strategies often report:

• More consistent year-round results
• Reduced overall energy costs
• Better environmental control
• Less stress on plants during extreme seasons
• Extended equipment lifespan (each system used half the year)

"UK here too. Been MH/HPS for 20+ years now... My main issue is heat, too hot in summer but that heat comes in really handy in winter."

Is a Seasonal Strategy Right for You?

Consider these factors when deciding if a seasonal approach makes sense for your situation:

• Climate Variation: The greater the seasonal temperature differences in your location, the more beneficial this approach
• Budget: Initial investment in two lighting systems is required
• Growing Experience: Comfortable adjusting growing parameters between lighting types
• Space Constraints: Need storage space for the off-season lighting system
• Energy Costs: Higher electricity or heating/cooling costs make this approach more valuable

For many growers, especially those in regions with distinct seasons, this approach represents the best of both worlds—combining the strengths of each lighting technology while minimizing their respective weaknesses.