Any grow light has to be immediately over the plants. In most cases, within a couple of inches of the tops of the plants. That's the only way the plants intercept a lot of the light. If you have a lamp on the ceiling, most of the light will be illuminating the walls, not the plants on the floor. It's matter of degree. Would such a light work? Sure, but very poorly.

You could probably drop a wire from the overhead fixture to a hanging grow-light over the plants on the floor.

If you got a whopping bright bulb, consuming loads of power, maybe plants eight feet away would get enough light. I know of no such bulbs. They'd be dangerous.

Grow-lights for plants replace sunlight. The sun is BRIGHT! REALLY BRIGHT!

Ironically there is no plug in this part of the bathroom, or I could invest in a grow light stand to put in there. That's why I never previously did much seed starting, we have so much shade at our house and no space really for a seedling growing set up. The heater is already operating on an extension cord . . .

You can easily get an a/c socket that screws into a regular (A19) light bulb thread. Sorta like this

https://www.homedepot.com/p/Leviton-Socket-with-Outlets-White-R52-01403-00W/100184555 (though they make them without the lamp sockets).

Screw that into the light fixture up top. Then the glow-lamp just hangs down on it's own a/c cable that is connected to that a/c socket up top. You'll have to do some diddling to make sure it hangs with the lamp pointed down, the right distance off the shower floor. This sounds very doable. A walk-in shower sounds like a great place to start seeds.

Hubs and I are actually going to implement said scheme today! We're going to use a shop light frame and two tubular grow lights. We found this instruction manual online, https://extension.umd.edu/hgic/topics/pvc-light-stand but hubs just said it would be easier to just mount some hooks on the ceiling and hang the light from an adjustable chain. We have some old tables in the garage that will fit in the shower stall, to raise the plants up on.

Smart move! Don't feel you need a real "Grow-Light" though, BTW. They're expensive. If you're doing indoor gardening, through plant maturity, those might be optimal, but for seedlings, who cares? The seedlings don't. Regular T12/8/5 "daylight" fluorescents will do fine. Again, the lights should be just an inch or two above the tops of the plants. So make sure the lamp height is easily adjustable. As the seedlings grow, you'll have to move the lights up (or the plants down).

Yeah, actually that's what I'm buying. They say "daylight" on them but are also marketed as grow lights. Not terribly expensive. I'll report back when we get it all set up!

It ain't pretty but we were trying to spend minimal money and use salvaged stuff from the garage. Those pots are not optimal, but I plan on transplanting the tomatoes to smaller pots if they survive. This year I am basically going to be growing some tomatoes just as a seed source for next year since I am about a month and a half behind. I had planned on getting tomato plants from my usual benefit plant sale fundraiser but it has been cancelled this year. Not due to the plants, due to not having volunteers to run it. Not sure I will have that great of a harvest. But some trials of various varieties to see which ones perform best. I don't have much of a spot for starting seeds but if this works I may expand it next year.

I haven't really found my ideal tomato yet for canning in my garden. I love the beefsteaks for flavor but the folding is a pain to peel around. These seeds are what I could get, my friend sent them to me. Most are heirlooms with the folding, except one, "Golden Jubilee" which my friend says she likes for canning. Could not get a hold of any "Rutgers" seeds this year.

Actually, optimal humidity levels for tomato seedlings is 80-90%. Bet you can manage that in a walk-in shower. Just keep an inch or so of water in the basin, below the plants, and keep the doors closed.

Is there no safety legislation about electricity in bath /shower rooms?

First of all, this is a handicap accessible shower "room." It's much larger than the typical shower, even the typical walk in one. It's the size of a walk in closet with a doorway and lined with ceramic tile and a composite floor, not glass panels. It has two windows. We do not use it at all, and have never used it as a shower. It's also in a large separate room off the actual bathroom, with nothing in it. In the US, many showers and bathrooms have lights in them due to their large size.

Ok. Obviously bathrooms and showers have lights in them but it's just that electric sockets, lights, other than specific sealed bulkhead types certified for bathrooms, and regular light switches are all illegal in a bathroom here, however large it is. It just seemed dangerous to have extension cables, ordinary lamps and sockets in a bathroom. And even more so with basins holding water.

Same with a kitchen. Lots of water. Lots of electricity. But you don't take showers in your kitchen. The rule here should be that if the code police come around, make sure you're not taking a shower with your plants while the light is on. Certainly an extension cord hanging from a ceiling light in a shower stall is dangerous for people taking showers.

Again, we have NEVER used it to take showers in. It is my folks house, and when I visited I once took a shower in that bathroom because there was a problem in the main bathroom, the one with the tub and shower that we actually use. The floor was so slippery in there I almost killed myself. I urged my folks not to use it as well. Shortly thereafter my mom died from a fall, (not in the shower) and my dad moved out. Two years later my husband and I moved in. From day one for the last five years no one has used that shower. I had dreams of redoing it, maybe even putting in a soaker tub in that space, but no more. There is no other water going on in that room, the sink and toilet are in another room. So maybe doesn't meet code, but isn't being used unsafely either, and for six weeks does not seem to be a big deal. We can't use the shower water, it is treated with salt. We use rainwater from our outdoor rain barrel, and a small watering can.

I should have made it clear that I was joking. OF COURSE you aren't taking showers in a former shower stall where you're growing plants. Just like you aren't taking showers near an electric stove in a kitchen.

Yes, I knew you were joking. I was just reiterating that I am not cavalier about electricity and water . . . I'm a science teacher so I know the basic physics involved. Ironically, the total lack of any use for that large space with two windows for light, was what prompted me to think that it would make a good seed starting area. Unfortunately, the main reason I have never started seeds indoors at home before is because you really need a south facing site with strong exposure to sunlight, something totally lacking at my home unfortunately. I don't have the money right now to invest in a whole big light tray, nor the space in my home since the south facing area of the house is where the living room, family room and dining room are, with zero extra space. Unfortunately, my book addiction has taken up a lot of wall space! Initially I thought the shower room with the windows would be great, but I forgot just how much light seedlings need to grow strong. It's still going to be touch and go. Not sure what I am going to do next year if I want to get into this in a big way.

receptacles in wet locations like bathrooms and kitchens are required to be ground fault receptacles. Switches and light fixtures are pretty much whatever you want. It doesn’t make any difference if you’re not looking to pass a building or electrical inspection.

Eh, maybe if I decide to use the room next year I will have my husband design an adjustable frame for the lights and we can use an extension cord and run the connection for the light from the next room electrical outlet. Or I will pay an electrician to run an outlet into that room. The light bulb adapter cost me three bucks, I had all the rest of the hardware.

Then again, it might be a kick to take a shower surrounded by seedlings!

If you want more space for seedlings, you could probably fit them all in the shower if you do a multi-level design. Lots of smaller trays stacked on top of each other.

In our burg, code is that receptacles in bathrooms have to be no less than three feet away from a shower, and of course need to be GFI-enabled. And, oh yes, if you're trying to reproduce sunlight, you need a LOT of light. The sun is VERY bright. Some would say, hey, I can read just fine, must be plenty bright. Wrong!

Man I am getting it from both ends! I showed my Dad my project and he was worried I ruined the shower! I really don't care, if the tomatoes eek by for a few more weeks until I can get them into the ground, it will all soon be pandemic history. But I do need to figure out a long term way to start seeds if I am going to do this properly next year . . . I used to work for a greenhouse so I could always ferret away a few plants for myself, but no longer, at least for the near future. It's a space issue more than an electricity and light issue. The shower room does have some potential. I had also thought about getting a multi tiered shelf and setting it up in the living room, but that is more expensive and also has kind of an "in your face" footprint for my home . . . the living room is more of a tiny parlor/sitting room. The family room is much larger but has virtually no windows or wall space, a la "open concept." There is a big sliding door to the back porch, but it is a shaded north facing thing so no good. Plus it is the door to the outside as well as being the only source of natural light in there so not a space to put a seedling starting shelving unit. Tiny kitchen, dining room full of books, two small bedrooms with very little wall space not taken up by clothing storage . . . the huge shower room off the master bedroom, is starting to look better and better! I will have to forgo my soaking tub, but maybe someday I can redo the whole bathroom to incorporate a whole indoor gardening motif!! If only my windows didn't face a busy road . . .