You read a brief overview of the history of lighting technologies as they relate to growing vegetables at home under lights. While other lighting technologies are available, except for in specialized cases, like where penetrating foliage is required, it is hard to see why technologies other than LEDs would be used now. The prices are reasonable, the power consumption is very low for the amount of light produced, and they are readily available.

As I mentioned back then, light toward the blue end of the spectrum, with numbers toward 6500K are best for proper leaf and stem growth, while light toward the red end of the spectrum, between 2700K and 3500K are best for flowering and fruiting. To look at them they look more like white and yellow.

If you are like most gardeners you don’t want some of your plants to flower and in your garden room you have much more control over that than you would outside. You simply scatter the higher frequency bluer light everywhere in the room, with higher intensity lamps, while using focused lower frequency redder light on the plants that you want to fruit.

I accomplish this by using a regular drop light with a reflector. These are not expensive, and are very widely available. I simply suspend these from hooks that I put into the ceiling. The weight is not very significant, much less than a hanging basket of plants. As the plant grows, you simply raise the light. If you have several, you could switch to a higher lumen bulb. LED bulbs last a long time and it’s likely that if you do this regularly, you will build up a small collection of bulbs that you don’t use all the time. I currently have three.

Though it is much less than other common lighting technologies, they do produce some heat and should be kept a small distance from your plants. How far depends on the individual light. Usually an inch or two is fine. For lower intensity lights, it could be less.

If you have ceiling fan with a light socket beneath it, and if the socket can take heat, you will want to use a shop light LED bulb. If it is an older fixture, designed for incandescent bulbs this will not be an issue, however, this is much more light than people who aren’t gardening normally use in their homes, and some newer, less expensive fixtures may be designed to only take normal household LED ranges.

When new, usually the maximum wattage is shown with the lamp. Use the actual wattage number, not the one that compares its brightness to that of incandescent bulbs of a certain wattage. That number might be larger on the packaging.

Using an internet search engine, type LED 6500K shop light, you are looking for one that uses up to 100W of power and has a standard base. This is important, because these often replace lamps that used so much power with older technologies, they have a special base so you don’t accidentally put a normal light bulb in the high powered socket, called a “mogal base”. You don’t want those, you want bulbs for a “standard base” also know as E26 or E26/27.

I wish I could tell you that one light would be enough to enable you to grow a whole room of vegetables. That is not the case. If it were a room of slower growing, shade loving houseplants, it’s probably more than enough, and you could grow a beautiful display.

We, however, are concerned with fast growing vegetables. The vast majority of these were meant to be farmed out in the full sun. While that one light would probably keep them alive, they would not grow at the desired rate.

As I mentioned earlier, the human eye adjusts quickly to variations in the intensity of light, and for this reason it is impossible to judge it with your eyes alone. Once your plants are growing, they themselves will give you clues as to whether or not they are receiving adequate light.

In the meantime, however, your best bet is the a light meter, or a light meter application on your cell phone.

Things get tricky here, and more difficult to explain than I would like, at the level that I have been able to keep this book on so far. Plants have different light requirements, and it’s much easier to grow some vegetables indoors than others. The difference between them is the light requirements.

We are shooting for 10,000 LUX, at a minimum, of regular household light at the leafs of your plants or 5000 LUX of light from a specialized LED lamp for plants. These are considerably less than actual sunlight, but much brighter than you would normally keep your home. The intensity of light diminishes quickly with distance, and our LED lights produce relatively little heat so we can put them near our plants. Many things, like spinach, will not do well at that level, even though lettuces, mustard and cabbage do.

I know of no good reference for the amount of light required for different crops. What I have learned is from experience. I would like to find such a reference, but so far, I’m building it myself. That said, there has been a lot of great horticultural science done and this chart probably exists somewhere.

Also, light can be focused with reflectors. Bulbs intended as home spotlights have reflectors built into them. Using these can greatly increase your focused light levels for power used because they direct all their light in more or less the same direction.

Unfortunately, for our purposes, most people want higher frequency light of of these bulbs, because they are using them to light some object, or for security lighting, while we are willing to scatter high frequency light to all our plants, only focusing the low frequency light on the flowering plants.

Still, 10,000 lux is quite a bit of light, even if it is about the minimum for good vegetable growth. If a seedling come up spindly, that is very long, this is a clear sign that it is not getting enough light. Remove that seedling, you might rinse and it eat it, depending on what it is. Get more light on the area by hanging a bulb nearer to it, and try again with a different seed.

Another sign of insufficient light is when a plant goes through its seedling phase normally but then grows sparse foliage, and becomes tall. The remedy is the same.

A third case is where the plant grows normally but is nowhere near ready in the time that it would have been outdoors. In many cases you can just wait a little longer, or you could eat it young. While it could be something else, like plant nutrition, if it looks otherwise healthy, and very leafy, it’s not quite getting enough light. You may not have to increase it much.

These are all symptoms of insufficient high frequency light. As I have mentioned a couple of times already, and may again to help you remember, all your plants need that, while only your flowering or fruiting vegetables really need the low frequency light. Please excuse my over-simplification here. Again, I am writing for beginners, and I am remaining on focused on what is needed for basic success.

You can expect to learn enough from this book to grow certain salad greens and herbs that do well under lights, as well as tomatoes and similar nightshades, such as peppers, ground cherries or tomatillos. Beyond that, I am trying to give you enough information to make good guesses in your future experimentation. I think for many people, these are the things that want most from the garden room, because they are the things they eat raw.

Remember that there is time involved. Plants come in varieties, and in this work, I generally use quotation marks to indicate a variety name. I’m going to do that at the very beginning of the next paragraph.

“Rover” round radishes are ideally ready only 28 days after the seeds have been planted. I arrived at this number by adding the days to sprout to the days to harvest on the seed packet. Though I am using these numbers, both indoors and outdoors, I’ve gotten wildly different results from the package. My conditions are just unlike the seed farmers’.

While they don’t have to be the “Rover” variety specifically, small round red radishes make a good general lighting test because they are quick, usually ready in a month or so. If the radishes grow, you will be able to grow a wide variety of salad greens. Not that these really take all that long. “Dragoon” romaine lettuce, for example only takes about 50 days from the time you plant the seed.

This growing time is one of the primary reasons it is useful to have something like that salad tower that contains a lot of plants. If you grew only one romaine lettuce at a time, for example, you’d only get a salad every 50 days