We have put together some of the questions we get the most often on LED lights and best practices to optimize your lighting solutions investment. If you have additional questions, please use the form on the Contact Us page or email us at


What spectrum is best?

When it comes to LED lighting for crop growth, there is no perfect spectrum for everything. The best spectrum requires a situational conversation, and is not a simple answer.

The light spectrum is a variable that interacts with other environmental factors such as light intensity, CO2 concentration, temperature, nutrition, plant morphology, and genetics. Therefore, a balanced, full spectrum approach is often the most sensible option to ensure favorable results regardless of these many variables.

However, in some cases, it may be necessary to adjust the light spectrum for certain setups to focus on specific growth aspects. For instance, to encourage expansion, a spectrum higher in far-red light may be used, while a spectrum heavier in blue and possibly UV may be utilized to enhance compactness, coloration, and taste/smell/chemical intensities.

In addition, when selecting the ideal spectrum, we must also consider the impact on worker safety and the operational costs and electrical efficacies associated with different spectra. Ultimately, determining the optimal spectrum requires a situational discussion that considers all of these variables. In conclusion, there is no single perfect spectrum for LED lighting in crop production, and it is important to evaluate each setup on a case-by-case basis to determine the most suitable spectrum for each specific scenario.

How much light do I need?

This is the single most important question in a light plan. Too little light will lead to bad results regardless of all other lighting features, and too much light is a poor investment. The amount of light provided to the plants is a crucial factor that determines the overall success of the crop.

The appropriate amount of light to deliver to the plants depends on the crop type, environment (greenhouse/indoor, temperature, CO2, etc.), the growth goals, and the business situation (budget, electricity cost, utility incentive availability, target customer preferences).

Although some general guidelines may exist, the best approach is determined through a comprehensive discussion that includes rounds of calculations and modeling to fine-tune the solution.

Determining the optimal amount of light for LED lighting plans is a complex task that requires a thorough analysis of all of the above factors. Let’s discuss your specific needs and objectives to design a tailored solution.

Which light model should I use?

To maximize cost-effectiveness, we generally use the most powerful light that maintains uniformity and avoids excess lighting. In a greenhouse, a light bar is preferable to a higher-shadow light. In confined spaces, a multi-bar or multiple lower-powered lights may be necessary to achieve uniformity without requiring a large height and/or grow area size.

Additional considerations include the shape of the grow area relative to the dimensions of the lights, placement of other equipment to avoid, and special features like control, mounting, special voltages, and extra protection. Ultimately, there is no one-size-fits-all solution that is both cost-effective and convenient. We can help identify your unique requirements to create a solution that is the right fit.

How high should the light be?

As with many lighting questions, generalities can lead you wrong. To achieve optimal results, we typically recommend that the height of LED lights be between 50% to 100% of the light spacing, with 60-75% often being ideal.

For example, in a greenhouse with lights on 12’ centers, the minimum height should be 6’, and around 8’ is great. Higher heights can result in a lot of wasted light outside the grow area. A lower height is preferable for a small quantity of lights to avoid waste, while a higher quantity of lights can be positioned higher with less loss since most lights are not on the edges where light can be wasted.

This guideline applies to indoor light bar setups as well. For multi-bar lights with 6-12” light bar spacing, the ideal height is around 9” from light to canopy, but higher is acceptable in highly reflective rooms or when neighboring lights are present. Let us help you map this out for your space, so you can make informed decisions on the appropriate lighting.

How should/can I control the lights?

Control strategies for LED lights depend on the setup, goals, and existing equipment. In simple setups like indoor growing of greens and herbs, a timer is often sufficient, while in higher intensity situations like cannabis, dimming is important to allow gradual increases in intensities as plants grow and acclimate.

For small setups, use built-in dimming dials for minimal cost and complexity, but for larger setups, use dedicated light controllers or tie the lights into a broader environmental control system to reduce equipment. TotalGrow lights should be able to work with any controllers. It is recommended to have a timer cutting power during dark hours, rather than relying on dimming, to ensure no chance of night interruption triggering vegetative growth of short-day plants like cannabis. 

In a greenhouse, it is ideal to have a photosensor monitoring natural light levels to reduce LED light levels when there is ample sunlight. For lower intensity setups, dimming is not helpful and the sensor should simply cut power to the lights. For a higher intensity setup where the majority of the light is coming from the LEDs, dimming is generally worth utilizing. Most greenhouse climate control systems offer this functionality already and TotalGrow will simply help coordinate these features without adding a new interface. For smaller/medium greenhouses a simpler control system may be in place and TotalGrow can offer a complete lighting control system.

What happens if there are problems with the lights?

TotalGrow Lights have a 5 year warranty and we will promptly address any issues with the light fixtures.

The most common issue that can arise with LED light fixtures is not the LEDs, but rather the power supplies that convert AC power to the exact DC voltage/current needed for the diodes. Lower quality lights will fail early because of this, but even a high quality light has a small chance of a problem given enough time. We will provide diagnosis and resolution no matter how the problem presents.

Let us know if your plants are not growing as expected and we’ll investigate light placement, hours of operation, and environmental conditions, etc. to determine the best solution.


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