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A Guide to LED Grow Lights NZ

During a growth cycle, plants react to varying light intensities. These different light ratios influence how the plant responds and develops in terms of taste, nutritional content, form and flowering. In the horticultural field, light is measured in photons, and there are several metrics used to measure the efficiency of lighting in a growing space:

Metrics to measure the grow light efficiency 

Photon Flux (PF)

The number of photons in μmol/s emitted from the light source. This metric covers the whole spectral range that plants are sensitive to, while PPF refers to just the photosynthetic region. 

Photon Flux Density (PFD)

The number of photons which actually reach the plant from the light source 

Photosynthetic Photon Flux (PPF)

The number of photos emitted from the light source in the range of photosynthesis (400nm – 700nm) 

Photosynthetic Photon Flux Density (PPFD)

The number of photons that actually reach the plant from the light source within the photosynthesis range (400-700)

In order to create different light ratios, the LEDs grow lights for sale at Herbal House are the best option, as they have a narrow peak bandwidth which can be optimized for different plant species. 

Types of Plants Impacted by Light 

Short Day (Long Night) Plants

Plants that need a long duration of darkness to flourish. Flowers only bloom after the plant receives less than 12 hours of light. Examples of short-day plants include those you’ll see during Spring or fall: Chrysanthemum, kalanchoe and ipomoea. 

Long Day (Short Night) Plants

Plants that need more than 12 hours of light, and only a short period of darkness to bloom. Long day plants typically flower during the Summer, and includes a lot of garden vegetables like lettuce, potatoes and spinach. 

Day Neutral Plants

These aren’t impacted by day or night. Examples include vegetables like cucumbers and tomatoes. Their flowering can only be controlled by the natural development of the plant, or changing their surroundings to a low temperature.

What type of light do plants need? 

It’s the intensity (quantity), duration (photoperiod) and quality (spectrum) of the light that impacts the plants and combining these measurements changes the plant form (photomorphogenesis), growth direction (phototropism) and flowering time (photonasty). The amount of light or photons that a plant receives each day can be measured as Daily Light Integral (DLI). 

Chlorophyll absorption within the leaves of the plant will determine the growth rate, as this is where photosynthesis takes place. To adjust the morphology of the plant, light will need to be absorbed by the phytochromes which react to the environment around them. 

How Does Light Impact the Plant? 

There are 3 mains ways in which lighting impacts the plants: Plant form, growth direction and flowering time. 


This is the process in which plants convert light into a chemical energy. Light energy is absorbed by chlorophyll in the plant’s leaves and then used to enhance the plants growth, while emitting oxygen as a waste product.


Indoor grow lights NZ can impact the plant’s form and size through photomorphology. Growers can decrease stem length of certain plants by using a specific lighting quality. 


The duration of darkness will impact the formation of the plant’s flowers. Plants tend to be either a short day, or long day bloomer.

By controlling the amount of time plants are exposed to light can help to change the flowering, leaf build and germination processes.  To influence the flowering, growers can use a combination of hyper red (PR - 660nm) and far red (PFR - 730nm).

Phytochromes react to these light spectrums to replicate the effects of day and night. PFR is initiated through use of red light at 660nm to provide daylight, and can be reverted to nighttime by activating a far-red light of 730nm which converts the light back to PR.

By creating day and night for the plant, growers can control when plants flower, without having to take seasons into consideration. The easiest way to control light exposure is by using the types of indoor grow lights online at Herbal House. 

Types of lighting application 

There are several lighting applications that horticulturalist use, all depending on the type of farming and lighting they’re working with. These are top lighting, inter lighting, vertical farming or consumer products. 

Top Lighting

Top lighting supplements sunlight, and therefore is held above the plants. The application helps to enhance the process of photosynthesis and the quality of the plant.  Top lighting is common in greenhouses. An example of top lighting would be high-pressure sodium (HPS) but due to the heavy power consumption of the HPS, and the heat they emit, this type of lighting needs to be placed further away from the plants. 

Inter Lighting

LEDs are perfecting for inter lighting. As the name suggests, inter lighting is when lighting sources are placed in between the plants and leaves. This means that both the top and bottom sides of the leaves are in the light, rather than the bottom sides being in the shade (this is the case with top lighting). LEDs are better for inter lighting as HPS luminaires can damage the plants with their heat. 

This type of lighting is typically supplemental, rather than sole-source and is used alongside natural daylight in greenhouses.  

Vertical Farms 

As the name suggests, vertical farms are when the plants are grown in layers on shelves vertically, rather than side by side. Vertical farms are used for saving space and growing a large crop in a small space. In such cases, light is placed directly above the plants. Indoor LED grow lights are used so that the light produced is ‘cold’ light and does not damage the plant. 

Vertical farm plants grow under completely artificial, sole source lighting. This means farmers can control the duration, intensity and quality of the light the plant receives. In order to yield the best plants from a vertical farm, white or blue light is needed. 

Grow Bulbs 

Indoor grow lights are perfect for the horticultural hobbyist. This lighting doesn’t create rapid growth, but allows plants to flourish under low light conditions indoors. A variety of white LEDs are used with a converter to create different lighting mixes throughout the plant’s growth cycle. 

Grow Boxes 

Grow boxes are the latest lifestyle trend which allows people to grow plants, herbs or vegetables within their home. The boxes use completely artificial light, giving growers the flexibility to adjust the lighting conditions when needed. LEDs with different wavelengths are used to create the perfect lighting recipe for the plants. Grow boxes come in all shapes and sizes, so setting up your grow space is different for everyone.