When it comes to greenhouse growth, Ontario is the hottest spot for it in Canada. About 60 per cent of the country’s greenhouse area is in this province – and whether you’re growing vegetables, fruit, flowers or cannabis, every space requires energy.
So, how can you maintain your greenhouse’s productivity, while still keeping energy costs in check? One of the best places to start is lighting. Installing or upgrading to LED lighting can lead to energy savings of between 35 and 50 per cent compared to high pressure sodium lights, which are common to Ontario greenhouses.
LED lighting also lasts between five to 10 times longer than high-pressure sodium options, which can help you save on the costs of replacing your lighting over the long term. In many cases, greenhouse operators who invest in energy-efficient LED lighting see a payback within two to three years, especially with the help of rebates.
LEDs can be the sole light source for a greenhouse operation or they can be used as a supplement to other types of artificial light. In general, here’s what you’ll need to think about before you make the move to LEDs.
Consider how many LED lights you’ll need. If you’re unsure about whether LEDs will be right for what you’re growing, consider starting with a pilot project in a small area. That way, you can experiment with the number of lights, their intensity (how much light they give off), placement and colour to see how it affects your plants’ productivity. Regardless of how many lights you want to start with, Save on Energy incentives are available to help you save up to 50 per cent on the cost of upgrading.
Newer LED systems allow you to have control over spectral light, which can help optimize your growth. Some researchers, including scientists in Ontario, are experimenting with how the colour of light affects certain plants. A team out of the University of Guelph, for example, recently found that pure blue light promotes better flowering over red light in certain plant species. However, they found it could also cause plants to stretch. So, one option could be to use pure blue light in early stages and red light later. Consider which crops you’re growing and what impact lighting colour may have.
The distance between your crops and lights will differ, depending on what you’re growing, so consider how to optimize lighting placement. Using a light rack with a pulley system can help give you more control over how close or far your lights are from your plants.
Using smart LED lighting may also help you improve productivity in your greenhouse. With smart lighting, you can have more control over lighting intensity, duration and colour, or spectrum. This may be helpful for supplementary lighting for crops that require more intensity to thrive.
How and where you use LEDs will depend on what you’re growing. Growing cannabis effectively will require a different setup than, say, tomatoes, leafy greens or flowers, so it’s worth keeping in mind your future goals for your greenhouse and whether you may change what plants you grow.
As with any energy-saving project, it helps to start by assessing your space. Before determining how much lighting you need, consider the amount of time your lights need to operate, the output or intensity of light you need (depending on the crop) and the area of production.
Notably, think about how much light is available at the crop level, so keep in mind what may be potentially blocking or amplifying light levels, or how you can better control it, through curtains or other shading systems.
Knowing your daily light integral, or DLI, is a useful way to figure out how to best use supplemental LED lighting. It’s a measure that lets you know the intensity of natural light your plants receive per square metre in a given day. This will change depending on your location and the time of year, but overall, your greenhouse’s DLI affects plants’ flower number, root growth, branching and yield – in other words, how well they thrive.
Once you have that as your baseline, you’ll be able to make better decisions about how much additional lighting you need to grow your particular crops. Consider working with an agronomist to help you determine how to use your natural and supplementary LED lighting most effectively for whatever you’re growing.
To gain energy savings elsewhere in your greenhouse, consider how lighting may affect other elements of your operations, such as irrigation, heating and ventilation. For example, LEDs don’t give off as much heat as high pressure sodium lighting, which may require you to adjust the heating and humidity in your greenhouse.
Along with saving on the costs of LED lighting, you may be able to save on sensors, dimmers and other energy-saving equipment within your greenhouse through Save on Energy incentives.
In any case, making energy savings a priority for your operations is a great way to grow your bottom line – and gain a competitive foothold in the province’s blossoming greenhouse sector.