Winter is not just a dull and dark time for us, our plants are feeling it even more! No light means no food for them, and no food means no more growing! So, it is clear that more light is a good thing and fortunately there are many different indoor lighting options, but how to pick the right one? Because there are so many it is hard to know what is best.

How much light do plants need?

Light needs for plants vary with the type of plant. We have grouped some plants together according to light requirements.

Low light plants.

These plants can use 10-15 watts = 50-250 lumens p/sq foot.

Medium light plants.

These plants can use 15-20 watts = 250-1000 lumens p/sq foot.

High light plants.

These plants can use 20 watts or more = 1000 lumens or more p/sq foot.

So what is a watt and lumen? Here is some handy information to know when picking out lights.

Lumens, how much light a bulb or fixture provides. The higher the number the more light it will produces.

Watts, how much energy a bulb consumes. A good rule to follow for knowing how many watts you need is.

Kelvin (K), units to measure colour temperature. To see if it is warm or cool.

CRI, Colour Rendering Index, measures how colour looks in a room. A CRI of 0 means all colours will appear black. A CRI of 100 means this is how colour will look under natural sunlight.

What is light spectrum?

Blue Spectrum (Cool)

Blue helps plants produce chlorophyll. This is the pigment they need to grow. Blue light also helps with germination and root development for seedlings.

Red Spectrum (Warm)

Red light regulated a plants growth and allows them to produce flowers and fruit. It also assists greatly with leaf expansion and stem growth.

Green Spectrum

Green light allows plants to get the maximum benefit from photosynthesis.

Common plant growing bulbs.

LED lights

Compact Fluorescent Bulbs

Fluorescent Bulbs

How do I know if my plants need more light?

Pests and/or disease may be establishing

Plant Light Tips

Fruit and Flowering Plants

Need more red than blue. 1-4 blue to red with 3000K is perfect.

Seedlings and Starters

Need 2000 – 3000 lumens. Full spectrum with more blue. Light should be close to prevent leggy-ness. LED is best as there is little to no heat.


Need full spectrum with 1000 lumens p/sq foot.