Home Improvement

Lighting For Indoor Plants and Starting Seeds

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Plants use light to convert carbon dioxide and water into the energy they need for growth, through a process called photosynthesis.

Seeds do not require light to germinate; instead they require warmth and moisture. Supplementary lighting helps establish strong roots and sturdy stems for faster germination of seeds.

Select a light fixture that can easily be moved over seed starting trays, such as fluorescent fixture with long, tubelike bulbs that produce both warm (red) and cool (blue) illumination. For optimal results, opt for fluorescent fixtures with long tubes producing both red (warm) and cool blue light (cool).


Fluorescent lighting was once the go-to source of supplemental plant lights for indoor gardeners, but has since been outshone by LEDs. Yet fluorescents remain easily available and easy to use; fluorescents make ideal grow lights for smaller seedlings or plants that don’t require as much light, such as seedling trays of seedlings growing from seed. Try 2-tube fluorescent systems equipped with one warm and one cool bulb and position them 2-3 inches above seed trays as they grow – use a timer so your lights stay lit 12-16 hours every day!

T5 HO (high output) fluorescent tube lights offer enough illumination for most indoor seeds and plants even when placed on heat mats, even when using T5HO bulbs that emit blue-tinged Kelvin scale values such as 4000K or 7500K bulbs. Furthermore, these cool to the touch lights don’t damage young seedlings and plants when touching. Look for tubes producing color values in this range to maximize success when germinating or establishing seedlings or seedlings requiring little light (other than lettuce). When purchasing tubes it is best to seek tubes producing blue Kelvin scale values such as 4000K or 7500K to maximize results when germinating or establishing.

Many people mistakenly believe they can just place indoor seeds in a south-facing window and expect them to sprout, but that usually isn’t enough sunlight for sturdy and robust growth. When faced with so much exposure to sunlight, seedling stems often stretch for it instead of staying put – the end result often being spindly plants instead of strong upright stalks.


Indoor seed starting usually requires ample light for optimal germination. Some seeds require special conditions like porous seed-starting mix. Most seed packages provide information on this matter and may even provide suggested dates such as eight weeks before your expected last frost date.

Standard incandescent bulbs do not offer enough wavelengths in the blue and red parts of the spectrum to provide adequate lighting for growing plants, while some halogen bulbs produce enough illumination at this wavelength to be beneficial, but these produce much heat and only last up to 3,600 hours before needing replacement.

Fluorescent lights make an excellent supplement light source, as they are inexpensive while offering the necessary blues and reds. Plus, fluorescent tubes are more compact than LEDs so they fit easily into an average fixture. There are even full spectrum fluorescent indoor plant bulbs available which screw directly into regular fixtures to offer more of the right wavelengths than typical household fluorescents; though finding these in garden centers may prove challenging.


LED (Light Emitting Diode) lighting has provided indoor gardening enthusiasts with an effective and cost-effective means of improving indoor gardening practices. LED lights offer many advantages over conventional lights, including energy efficiency and long lifespan. Furthermore, their low heat emission allows them to be placed closer to plants without fear of scorching or dehydration; plus the customizable spectrum makes LEDs suitable for all stages of growth.

Full-spectrum LEDs more closely mimic natural sunlight than traditional bulbs, producing specific forms of chlorophyll for optimal plant growth – for instance red light aiding flowering and fruiting while blue lighting supporting strong stems and leaves.

Standard LED grow lights cannot meet the lighting needs of most seedlings, leading to stunted growth and weak plants in homestead settings. We recommend investing in dedicated grow lights for indoor seeds and starting plants; otherwise, sunlight may damage them as their roots reach towards sunlight without receiving sufficient illumination from standard LEDs. Alternatively, high tunnels, caterpillar tunnels, or recycled milk jugs might offer better indoor growing solutions than sunny windows for creating indoor growing environments; otherwise seeds will stretch towards it without getting enough light needed for optimal growth.

Natural Light

Plants are popular decorative indoor elements and add a sense of natural beauty to our homes, while serving multiple functions, such as air purification and humidity regulation. Unfortunately, many plants don’t receive enough natural lighting in their current locations – supplementary electric lighting provides an easy and cost-effective solution to providing plants with enough light to thrive and grow.

Natural light refers to sunlight that we experience during daylight hours, covering the visible spectrum from violet at one end to red at the other and vital for all life processes, including photosynthesis. Artificial lighting usually contains blue-violet wavelengths while natural lighting offers broad-spectrum illumination that more closely mirrors that of nature’s sun rays.

Natural light is often defined in terms of any source that closely emulates sunlight; examples include full spectrum grow lights or shop lamps placed an inch or two above seedlings or plants.

To minimize shock to outdoor-grown plants brought indoors, it’s essential that they acclimate slowly. Start by keeping them in shaded areas for just an hour each day until gradually increasing this period over the course of one week so they become used to stronger outdoor lighting conditions.