Greetings all!
My wife and I live in Southern California, USA; our house is on top of a hill with NO shade from any trees; we have huge sliding glass doors and/or windows on the east, south, and west sides of our house. So, long story short, I believe we have TONS of ambient light. Still, some of my indoor plants (mostly concerned about large dracenae marginata) seem to want more direct light than I can possibly give them; they may grow fine for a few years, but at some point, they start to look less than robust. Don't get me wrong -- I am NOT one of these people who tries to grow full-sun plants in full shade, and then complains when the plant performs poorly.
One option of course is to move the ailing plants to someplace in the house where they get more direct light. I have done that with some, but some plants really cannot go anywhere other than where they are. I am thinking in particular of a huge pot of dracenae marginata (some stalks of which are over 8 ft. tall) -- this pot (a) won't fit anywhere else, and (b) provides an important decorative focal point exactly where it is. [Relatedly: I am a little concerned about the ambient light fading our couch, so I could move the couch to a closet, but then I wouldn't have anything to sit on when I watch TV; sometimes the functional costs of moving something outweigh the benefits].
So...apart from moving plants from their current locations...is there any way to compensate for the possibility that some plants aren't getting quite as much direct sun as they'd like? I have tried some "grow lights" before, and observed no significant effect, but I confess I have only used the 60 watt, bluish, "plant gro 'n' show" bulbs one can purchase cheaply at Walmart and hardware stores. Frankly, I never expected those to do much anyway, and consequently never really got into an appropriate lighting regimen. Are there any "grow lights" that actually work? If so, I am willing to embrace this option wholeheartedly this time. Are there some online sites I should visit to research this issue further, or is the whole notion of "grow light" effectiveness kind of a myth? What kind of lighting regimen should one employ with these kinds of lights (if indeed they have merit at all)?
Also: While I am not suggesting one can easily replace sunlight with chemicals, is there anything one can do with fertilizers to help a plant which may be getting less direct sun than it optimally requires? If I lived in a cave, my doctor might say, "You aren't getting enough sun, so you should take a vitamin D supplement;" are there any parallels for plants?
Thanks in advance for any guidance in this matter!
Chuck