A small guide to using grow lights in your garden

Tomato Plant growing in grow light

PART – 1 : Choosing the type of grow lights

Plants are autotrophs, which means they synthesize their own food by converting light energy into chemical energy and ultimately into food through photosynthesis. Now the light utilized by them is emitted through the sun naturally. But since we are shifting to crowded spaces with little or no exposure to the sun in our homes, it doesn’t mean you shouldn’t consider growing your own veggies. And in such cases, grow lights will come to the rescue. Even in some cases when you think you have a good source of sunlight, it might not just be enough.

The plants can be categorized as long day, short day and day-neutral plants. The names speak for themselves, short day plants require light for fewer hours to flower and produce fruits while long day plants require light for more hours and day neutral plants will bloom irrespective of the duration of light. Most summer vegetables and flowers are long day plants and may require grow lights. If the light in your garden space is not sufficient then short day plants and day neutral plants will also require them.

So how to decide which grow light is best suited for your needs?

Before choosing a grow light you should first know the difference between a grow light and a normal light.

All of us have seen a rainbow which has 7 colours. Each colour is a result of different wavelengths of light. For eg., red colour is emitted due to 650 nm wavelength. Photosynthesis occurs at a specific wavelength known as PAR (Photosynthetically active radiation) which ranges between 400 to 700nm. Normal lights do not emit radiation in this range, that is why we require to grow lights for plants.

There are different types of lights available in the market. The three most prominent ones are LEDs, HIDs and fluorescent ones. 

Incandescent bulbs – these are pretty basic bulbs which can work well with some amount of natural light. But these lights throw out too much heat which may damage the plants. So I would advise jumping on the next one.

Fluorescent lights – They produce less heat and come in a wide range of colours. They give out shorter wavelengths hence their use is limited. They can be used for germination of seeds, root initiation in cuttings or to improve the vegetative growth of seedlings. They can’t be used for fruiting, flowering or vigorous vegetative growth. There are two types of fluorescent lights available – tube style and CFLs. CFLs are a more compact version so they are more suitable for smaller spaces.

High intensity discharges or HIDs – These are extremely efficient, produce very little heat and as a cherry on top, they are cheaper than LEDs. They are of 3 types:

  • HPS – High pressure sodiums emit red orangish light which is great for the flowering stage of plants.
  • MH – Metal halides are used for the vegetative phase of plants as they emit blue wavelength of light.
  • CMH – Ceramic metal halides are kind of a mixture of both HPS and MH. They have a broad spectrum and can be used for vegetative as well as flowering stages of plants.

LEDs – Light emitting diodes are the latest addition to the market. They can be customized according to our needs; they can be coded according to the wavelength required and can be operated fairly easily. Their installation and one time buying costs may be a little high, but they are highly efficient in power consumption, long lasting, space efficient and can be customized. 

So as now we have learnt what are the various options available, we can make a wise choice according to our needs. Here is a small summary comparing all the available options.

TypesHPS, MH, CMHTube style and CFLs
Heat emittedVery lessVery lessHigh 
SizeSmallMediumLarge, CFLs are small
Wavelength/ SpectrumFull spectrumCMH – BroadMH – BlueHPS – redBlueish 
Energy consumptionHighly efficientModerate efficiencyHigh energy consumption
*Lifespan50k to 100k hours or around 14 years6k to 24k hours or 3 years15k to 25k hours or 8 years
CostMedium Medium to highLow

*Lifespan is just an average number based on some survey. Actual life span may vary upon your usage and care and maintenance. 

Part 2 coming up soon!!

Written by:
Antra Thada

Published by Reema

Entrepreneur | Author of 2 Ebooks | Gardener

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