I have had several inquiries recently about my use of grow lights for starting seeds inside, so I thought I would share my advice here for all of you to reference as well. There are several benefits to starting seeds inside in early spring. Not only does it extend the length of your growing season by 2-3 months, but it also gives you more control over cultivar variety (exponentially more options) and growth methods. If you are anything like myself, you have windows big enough to start seeds but they don’t get direct sunlight. As a result, your seedlings lean toward the window and as they grow they become “leggy” with brittle, elongated stems. This is a liability. Weak stems leave your plants vulnerable and ultimately make the hardening process, when transitioning to your outdoor garden, very difficult. Save yourself the headache and set your precious plants up for success by investing in some grow lights. Here are 5 tips to get your started.
- They do not have to be expensive. Yes, there are grow light sets that fall into the “hundreds of dollars” category but they are not necessary for the standard home gardener. I use this set offered on Amazon – Hytekgro LED Grow Light 45W Plant Lights Red Blue White Panel Growing Lamps for Indoor Plants Seedling Vegetable and Flower (2 Pack) that includes two lights for just $45. The listing is accompanied by a timer adapter and the light panels are comprised of both red and blue lights. This brings me to number two…
- Red and blue light. Both colors (wavelengths) play a role in plant growth. Simply put, blue light enables the development of chlorophyll which is the organelle responsible for converting carbon dioxide, water and solar energy into free oxygen and usable sugars. In other words, they make food which encourages robust stem and leaf growth. Red light plays a more broad role in the overall life cycle of the plant. It is required for germination as well as root, flower and fruit development. This is why you typically see that while both blue and red are included, there is a higher ratio of red lights present. If you are interested in reading more about the science behind lighting combinations I’ve included a few references at the bottom of the page.
- Distance matters. Most grow lights come with a user guide or manual in which they make recommendations for the distance that should separate your lights from your plants. This distance increases as your plants grow bigger but will ultimately be determined by the intensity of the light source that you purchase. I have found it best to error on the side of caution and add a few extra inches of separation to avoid burning my plants. Yup, that’s right. If the light is too intense it will burn your plants, just like the sun does when your seedlings aren’t properly hardened.
- Water from below. One way to reduce the chances of burning your plants is to water from below. When water accumulates on the foliage and then rapidly evaporates off it scalds the leaves. In using grow lights you are increasing the intensity of the light overhead and will therefore facilitate the evaporation process which exacerbates this issue. Avoid it altogether by keeping your leaves dry and watering from below.
- Maintain a normal light cycle. Plants, much like humans, require both a span of time when actively obtaining energy and a period of rest. AKA – sunshine and darkness. Many seed packets list sun requirements as both “full sun/part shade” and the required duration. (i.e. minimum 8-10 hours sun) Onions are a great example for this topic because their bulb development is regulated by the sun. When the length of day reaches a certain duration, the bulbs start to mature. The daylight required varies by cultivar which is why onions are typically broken up into “long-day”, “short-day” and “intermediate” or “day-neutral” classifications. When starting seeds indoors, keep an eye on the sunlight requirements listed for each variety and adjust your grow light cycle accordingly. Generally speaking, vegetables require 8 hours of darkness for healthy growth.
Like any other aspect of gardening, artificial lighting requires some trial and error. The five points listed above should be enough to get you started but try not to get discouraged if your first attempt is less than successful. If you are a grow light pro and have suggestions for light sources and/or methods that you’re willing to share, please comment below for the benefit of our readers. Cheers, friends!
- Photosynthesis under artificial light: the shift in primary and secondary metabolism
- The impact of red and blue light-emitting diode illumination on radish physiological indices
- Using different ratios of red and blue LEDs to improve the growth of strawberry plants
- Unraveling the Role of Red:Blue LED Lights on Resource Use Efficiency and Nutritional Properties of Indoor Grown Sweet Basil