Grow Lights

Grow lights are a gardener's best friend! You can use grow lights to propagate seedlings and cuttings, to supplement sunlight in a conservatory or greenhouse, or even to grow and bloom annual plants indoors without any need for sunlight whatsoever! These amazing devices will open up the whole plant world to you! With the help of environmental controllers and simple ventilation, you can simulate the conditions of your chosen plants' native habitats irrespective of where you happen to live in the world.

Grow lights: Revealing the Entire Kingdom of Plants to the World's Growers!

"What's wrong with the Sun?" you may ask. The answer is nothing, of course. Sunlight has been driving photosynthesis in plants for around 425 million years. But growers are definitely missing a trick by ignoring the possibilities of grow lights. Not only can you propagate plants at any time of year (when it may be too hot or cold to do so easily outside) but it's possible to grow any plant you can think of no matter where you happen to live in the world.

Sunlight is made up of different "colors" - this is what plants have evolved to exploit over millions of years. The general aim of artificial horticultural lighting is to replicate or supplement sunlight. Of course, given the Earth's tilt on its axis, different regions of the world have effectively evolved different types of plant life that have adapted to those conditions.

As indoor growers, we want to grow any plant we wish, no matter where we happen to live, and regardless of the time of year. The grow light is our key enabling tool in this quest-not only in helping us to broadly simulate the Sun, but also playing a key role in allowing us to recreate the native conditions of the plants we want to grow.

Sunshine Spectral Distribution Chart

If there's one type of sunlight, why are there so many different kinds of grow light? 

Different grow lights are designed and best suited for different applications. Propagating young plants requires a softer, kinder light, rich in the blue part of the spectrum. Growing up juvenile plants to maturity requires the same blue-rich light, but with greater intensity. Flowering plants generally require more oranges and reds to simulate the harvest Sun. You see, different plants want different kinds of light at various times in their lifecycle.

Next, let's break some stuff down. We'll start by taking a look at the three main areas in which grow lights are commonly used:

The Three Main Applications of Indoor Horticultural Grow Lights

1. Daylight Supplementation

Daylight supplementation in a conservatory with metal halide 400W high intensity discharge grow light.Grow lights can be used to supplement existing sunlight levels-this usually takes place in a greenhouse or conservatory. Here the light from grow lights is mixing with natural daylight. This technique is often used to over-winter semi-hardy or tender plants in cooler climates where they would not usually be able to survive. It can also be used at the beginning of the growing season to help plants get a head start or to induce multiple crops of annual plants in a given year.

2. Total Sunlight Replacement

Magnum XXXL - 8" Grow Light - this air-cooled grow light fixture is commonly used by indoor growers who wish to use grow lights for all their plants' lighting requirements in a total controlled, indoor gardening environmentOther indoor growers use grow lights to totally replace sunlight. This takes place indoors in well insulated rooms. Typical applications include the propagation of seedlings or cuttings for later transplantation-perhaps to the outdoors, a greenhouse, or to a "full-cycle grow room". Yes, it's possible to grow and bloom plants entirely indoors using grow lights-even light loving plants that thrive under intensely bright conditions. With total sunlight replacement, the light spectrum offered by the grow lights (often a combination of grow lights) is especially important as they are now totally responsible for all light energy the plants will receive.

3. Plant Steering and Spectrum Augmentation

Agro T8-Compatible LED Single Color Lamps can be used to augment spectral distribution of existing grow lights and / or natural sunlight, often to help steer plants towards generative production (i.e. flowering / fruiting)Specialist grow lights are used to augment the spectral distribution of daylight or existing grow lights. Certain "colors" or parts of the light spectrum are known to promote flowering and fruiting, increase the production of essential oils, help to combat plant pests and molds, or reduce vertical growth-i.e. keeping plants low and squat - more suited to indoor horticulture.

Grow Lights Articles

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PDF Infosheets

PDF: Before You Buy: Basic Principles

A grow light is probably one of the most exciting purchases any new grower can make. Whether used as a complete replacement for the Sun, or to supplement natural light levels, there are several different kinds of grow light available so it’s important to choose the size and type best suited to your application: i.e. propagating young plants, promoting vegetative growth, and driving flowering and fruiting.

Before You Buy: Basic Principles [PDF Link]