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Lighting for indoor plants and starting seeds

Quick facts

  • Sufficient light is important to growing healthy plants.
  • Select a plant with requirements that match the light environment in your home or office.
  • Supplemental lighting can make up for a lack of natural sunlight.
  • There are many types of artificial lights in different styles and sizes to fit your needs and budget.

Light is one of the most important factors for growing houseplants. All plants require light for photosynthesis, the process within a plant that converts light, oxygen and water into carbohydrates (energy).

Plants require this energy in order to grow, bloom and produce seed. Without adequate light, carbohydrates cannot be manufactured, the energy reserves are depleted and plants die.

How plants are affected by too little or too much light

Potted light green geranium plant with long thin stems and few leaves.
Plants like this geranium become leggy when not grown in enough light.
  • When plants lack light, they don't produce chlorophyll (the green pigment in plants), and plants can turn pale green to yellow to white.
  • Plant stems become “leggy,” meaning stems become long and thin and appear to be reaching toward the source of light.
  • A lack of sufficient light causes the plant to grow long spaces on stems between the leaf nodes (the point where a leaf grows out from the stem).
  • Plants without sufficient light may also drop their leaves, especially older leaves.
  • You may find that a variegated plant (leaves that are white and green) may revert to being solid green.
  • Flowering plants may fail to produce flower buds.
  • Plants exposed to too much light may result in scorched and bleached leaves.

Choosing the right plant for your available light

Succulent plant in a ceramic pot and macramé hanger in front of a window with an overhang casting a shadow.
Overhanging roofs can block light for part of the day. Even though this window is south-facing with plenty of natural light, the plants get indirect light for much of the day.

Before getting a plant or starting seeds, determine the quality and hours of natural light in your space. Then choose plants with light requirements that match your indoor environment.

While a plant may tolerate lower light growing conditions, more light may be required to promote dense foliage and flowering.

Low light

(PPF: 50-150 umol m-2s-1 / 50-250 foot-candles / 10-15 watts)

  • A low-light plant would be suitable for a north window or a fairly dark corner.
  • Low-light plants require little to no direct light. In their native growing environments, these plants are “understory plants” meaning they grow underneath the branches of larger plants.
  • Low lighting is not sufficient for starting seeds indoors.
  • In environments with less light, plants grow more slowly and use less water. Avoid overwatering by feeling the soil.

Medium light

(PPF: 150-250 umol m-2s-1 / 250-1,000 foot-candles / 15-20 watts)

  • A medium-light plant would be suitable for east-facing windows or located near a west-facing window, but out of direct light.
  • You would need artificial lighting for starting seeds in medium light.
  • Like the low light plants, these plants will not dry out as quickly. Avoid overwatering by feeling the soil.
Houseplant in a ceramic pot near a window with sunlight streaming through.
An unobstructed south-facing window will provide the highest level of natural light for plants.

High light

(PPF: 250-450 umol m-2s-1 / more than 1,000 foot-candles, more than 20 watts)

  • A high-light plant would be suitable for brightly lit locations such as south- or southwest-facing windows.
  • You may be able to start seeds without artificial lighting, but seeds that need more time indoors, such as tomatoes and peppers, may become leggy without extra light.
  • High-light areas can be warm, making plants dry out faster. Check these plants more frequently and water when soil is dry. 

Houseplants for different indoor light conditions

Just like choosing plants for sunny or shady areas of your outdoor garden, it’s important to choose plants that will grow in the existing light conditions indoors. And you may decide to add artificial grow lights to increase light energy to your plants.

The following houseplants are listed under the light conditions that provide the best indoor growing environment. 

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Adding artificial lighting

Artificial lighting can be added to make up for the lack of natural sunlight. Once you have an idea of the available light in your space and the plants you’d like to grow, you may decide to add supplemental lighting.

The most common types of lighting include LED and fluorescent bulbs, but you may see incandescent and high-pressure sodium bulbs when shopping around. There are pros and cons to using each type, and all can be found at local hardware stores or online.

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Authors: Julie Weisenhorn and Natalie Hoidal, Extension horticulture educators

Reviewer: Neil Anderson,  horticulture professor

Reviewed in 2020

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