
I found this on line and thought I would share it.
http://vegvariety.cce.cornell.edu/
A descriptive journal of hydroponic gardening projects; this blog replaces a paper journal, and is intended for my record keeping purposes. It is not intended to teach hydroponic gardening, but is rather a record, including editorial comments, of what has worked for me. Copyright © 2019 Hydroponic Workshop Weblog - All Rights Reserved.
The UV LED project box is simply suspended by a clip from the reflector shield, as I just could not bring myself to build any sort of support for it.
Day and Night:
Day length or duration of light received by plants is also of some importance.Poinsettias, kalanchoes and Christmas cactus flower only when days are 11 hours or less (short-day plants). Some plants only flower when days are longer than 11 hours (long-day plants), while others are not sensitive to day length at all (day-neutral plants).
Day Length:
Increasing the time (duration) plants are exposed to light can be used to compensate for low light intensity, as long as the plant's flowering cycle is not sensitive to day length. Increased light duration allows the plant to make sufficient food to survive and grow. However, plants require some period of darkness to properly develop and should be exposed to light for no more than 16 hours per day. Excessive light is as harmful as too little.. When a plant gets too much direct light, the leaves become pale, sometimes burn, turn brown and die. Therefore, protect plants from too much direct sunlight during summer months.
Supplemental Light:
Additional lighting can be supplied with either incandescent or fluorescent lights. Incandescent lights produce a great deal of heat and do not use electricity very efficiently. If artificial light is the only source of light for growing plants, the quality of light or wavelength, must be considered. Plants require mostly blue and red light for photosynthesis, but for flowering, infrared light is also needed. Incandescent lights produce mostly red and some infrared light, but very little blue light. Fluorescent lights vary according to the amount of phosphorus used by the manufacturer. Cool-white lights produce mostly blue light and are low in red light; they are cool enough to position quite close to plants. Foliage plants grow well under cool-white fluorescent lights, while blooming plants require extra infrared light. This can be supplied by incandescent lights or special horticultural fluorescent lights.
This phrase in particular caught my attention: " Plants require mostly blue and red light for photosynthesis"The LED grow light I am planning will only produce red and blue light. The theory being; why waste energy producing green, orange, yellow and violet, when the plant does not use, or need it? Plants reflect green light, that is why they look green to us..
As an experiment I have added a small project box containing six UV LEDs to the lighting supplied to the dianthus and ornamental pepper. The spectrum is in the UV-A range of near visible light. I have read several studies regarding the effect of UV light in plant growth. Some studies have concluded UV is detrimental, and some conclude it is beneficial. The LEDs I added have a wavelength between 395 and 410 nm. This wavelength is not considered harmfull and is very near the wavelength of blue light where photosysthesis begins.
Again, time will tell....

As I am continually starting small batches of seeds to keep the ebb and flow systems populated, I find the small propagator above to be ideal. It is a discarded container used to package greens from the supermarket.
Although we enjoy fresh salads in the winter, warm tasty greens are a welcome addition to our table.
This week we received a very elaborate 124 page full color catalog, printed on coated stock, from Baker Creek Heirloom Seeds. As a retired purchasing manager, I am aware of the cost involved in producing a catalog like this. It appears that these folks are very serious about marketing their seeds.
Our area in upstate New York is in the process of recovering from a severe ice storm. Everything was coated with an inch of ice, and hundreds of thousands of homes were without power for several days. As of today, there are still tens of thousands without power. One night the temperature was at four degrees, and it was not fun at all. The hotels were filled, and there were no generators, batteries, propane, or kerosene heaters to be found for sale anywhere in the area. We were without power for four days, however, I am fortunate enough to own a generator. Well, we have been through this any number of times over the years, so be prepared is a good motto to keep in mind.
As we progress into winter the seed catalog folks begin filling my mailbox with gardener's porn. Not that I mind in the least, as it sure beats credit card offers. (remember them?)
The plant in the photo is a Black Cherry tomato started from seed on November 5, 2008.