Indoor Grow Light Seed Starting

 This year I want to run an experiment and see just how much food I can grow in my new and improved garden. Normally, you can't put seeds or plants into the ground until mid-May or you risk frost damage or frost kills. I work out of state so if a frost gets announced, I'm likely not home to cover my plants and they get killed off. This happens every year to me. Young plants are a bit more susceptible to frost damage in a light frost but a "hard" frost will kill everything.

 To get as much of a jump on the growing season as I can get, I am going to attempt to start some of my seeds indoors under a growing light. "Real" grow-lamps are very expensive but research over the past couple months leads me to believe that seeds can be started and decent growth can be maintained with other types of lamps.

 There are three key characteristics to lamp light that determine whether or not the lamp will function as a grow lamp. First is the Lumens the lamp produces. A lumen (symbol: lm) is the unit of luminous flux, a measure of the perceived power of visible light emitted by a source. Just think of it as the brightness of the light, though there is more to it. The number of lumens the light has should be printed on the box somewhere. The generally recommended minimum lumen level for a grow light is 4,000 but over 6,000 is better.

 The second characteristic is the temperature of the light, measured in Kelvin. Note: this is not the heat temperature, but rather the color hue of the light. It is measured in degrees of Kelvin (K) on a scale from 1,000 to 10,000. Typically, Kelvin temperatures for commercial and residential lighting applications fall somewhere on a scale from 2000K to 6500K. A light bulb's color temperature lets us know what the look and feel of the light produced will be. Lower K lights are "soft and warm" and higher K lights are bright and harsh to our eyes. Grow lights need a K rating of 6,000 or above.

 The last characteristic is the color spectrum. True grow lights emit light from the red through the blue ranges of the spectrum. But that is one reason why they are expensive; it is more complicated to build a light that is multi-spectral. Most indoor lights have a narrow band of included colors. If you can afford a true grow light, go for it. I can't, so I selected a light that is more blue (the radiation is blue light but what the human eye sees is a harsh white light).

 If the grow light is your primary light source, which it is in my case, then it needs to be on for most of the day, 20 hours minimum. That can add up to a lot of electricity over the course of several months. So mine set up is going to run off of my solar electric system that I recently built.

 To keep other costs down, I wanted to use things that I already own and keep purchases to a minimum. You aren't saving any money growing your own food if you have to buy a lot of stuff. For my system, the only thing I bought new, specifically for the grow light build, was the light and it was $79 at Lowe's. The light I chose is one I recently installed in my mud room to replace a fluorescent light fixture that went bad. I replaced it with an LED light that provides 4,000 lumens at 6,500 K.

 I used an old gas grill that was on my scrap metal pile for the frame. I removed the top part, where the grill and flames would be, and striped it down to the frame.

I needed a surface to set the seed starting tray and was going to cut up some wood and figure out how to attach it when I remembered the grill rack inside the burner unit should be exactly the right size. So I attached that with small bolts and washers.

Perfect fit and I don't have to worry about the wood getting wet and rotting.

 I looked around the basement for a plastic bin that was big enough for the seed tray to fit inside and I also needed to insulate it because this will be in my basement where it stays about 50-55 degrees, which is much too cool for most seeds to start. I had saved the insulation from some boxes of mail-order foods we ordered when my wife was recovering from surgery. This is very good insulation and it was faced with aluminum foil (or aluminized Mylar, I'm not sure which). The insulation will allow the tray and seed medium to warm up and the aluminum will reflect more light to the plants once they sprout.

 For this first trial, I seeded the flat with three types of lettuce and one type of spinach. These are cool weather crops and both are frequently grown indoors with grow lights. However, these are older seeds, some from 2020, and germination rates won't be 100%. I planted extra seeds in each cell so if I get at least 30% germination I will be fine.

 

 As you can see here, this light, as powerful as it is, only draws 43 watts of electricity. My Delta Pro has a capacity of 7,400 watt hours and it is hooked up to 960 watts of solar panels, so it will never run out of power.

 The picture on the left shows the whole setup. I do have a small worry that there might be too much heat and the seeds won't sprout and if they do that they might get burnt back by the heat. But I am hoping that the water in the seed tray will prevent too much heat from building up. Evaporating water should cool it down as should the cool room.

 The picture of the right shows the interior of the grow box. The aluminum surfaces insure that the light is multi-directional so the plants, if they grow, won't be "leggy", as most plants get when light comes from one direction only.

It's an experiment and nothing is lost if it fails. But if it works, I will have a virtually free way to start plants indoors so that I can transplant partially grown plants instead of trying to start seeds outdoors before conditions are optimal. If this works, I could have fresh produce in June instead of September and that is a huge improvement. Fingers crossed.

	1 March 2024 Update: I have been monitoring this system since I set it up and it looks like I typically use 12% of the battery capacity over the 14-15 hours that there is no sun. Because of the mountain to my south, no direct sun hits the solar panels until about 9:00 in the morning. This early in the year, sunset is at 5:00. That gives me eight hours of sunlight, though there is some reflected light before and after those hours. Even so, the Delta Pro is fully charged by 12:00 noon and stays fully charged until the sun goes down. My peak collection time, because of the orientation of the panels, is between 12:00 and 2:00. During that time, I am inputting between 850 and 1,200 watts of electricity.