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Fluorescent vs. LED for Seed Starting

Like Velcro, cordless tools and wireless technology, innovations as a result of research by the National Aeronautics and Space Agency have definitely changed the habits of everyday life. These technological improvements extend even to gardening, and investigations into plant growth beneath light-emitting diodes, or LEDs, may permanently alter how plants are started and grown indoors. Though fluorescents have long been the standard light source for starting seeds indoors, LEDs have a number of advantages that may eventually make the use of fluorescents for plant growing as obsolete as the telegraph.

LED Qualities

Have a look at almost any electronic device — it probably has an LED someplace on it, usually to indicate that the device has power. Though these indicator lights have been deliberately dark, recent strides in LED technology have resulted in much more powerful lights which are gaining traction for use in general lighting in addition to for specific uses like plant growing. Contrary to fluorescents, which emit light in a broad spectrum, LEDs are designed to emit light in narrow bands, which may be combined to achieve particular outcomes. Long-lived, incredibly efficient and generating little to no heat, LEDs reduce the power invoice, rarely need replacing, don’t break easily and almost eliminate the need to give additional ventilation or airflow above plants to cool them. Although still costlier than fluorescents, new LED products developed especially for plant growing can be plugged into the wall and linked as needed to form a chain or set of lights.

Factors for Plant Growth

One disadvantage to LED grow lights is their psychedelic look. Since plants use only blue and red wavelengths of light for photosynthesis and growth, LED grow lights utilize mixtures of blue and red bulbs that result in an extreme purplish glow. Much of the analysis so far indicates that these blue and red LEDs result in stronger, more vigorous plant growth compared to fluorescent bulbs over the same time. However, since LEDs are designed to emit light in a really specific wavelength, and not all blue-red LEDs create an equal amount and quality of lighting, research continues on how many species of plants germinate and perform under different kinds of LEDs. Early adopters of this technology will probably find that greater products will become accessible as research progresses.

Fluorescent Lighting

Affordable, practical and widely accessible for most home growers is the traditional fluorescent tube. For years, the standard advice to indoor growers and seed-starters is to use a fluorescent fixture with one cool-light and one warm-light tube, suspended a few inches above the tops of crops. Full-sunlight spectrum lights produce the proper range of light wavelengths, however are far less energy efficient and produce heat which may lead to young plants to grow too quickly and eventually become spindly and weak. Bulbs need replacing every year or two, as older bulbs generate a high quality quality of lighting. Even though a fluorescent light device can look clunky and unattractive, the human eye perceives the emitted light as white, which makes it easier to live with in the home.

Seed-Starting Requirements

Not all seeds need light as a condition for germination. Some species require dark for good germination, like annuals like larkspur (Consolida species). Research remains mixed as to if LEDs or fluorescents are far better for seed germination; some research in Michigan State University indicates that seed germination rates are far better under LEDs, though other studies done at Wofford College in South Carolina indicate that no difference exists in germination rates involving plants started under LEDs and fluorescents, and that fluorescents may actually encourage better ancient root growth than LEDs.

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