Convert fluorescent shop light to grow light?

[jw]

Yep, just change the bulbs. My father was a plant guy and he had many grow lights. Just plain 4ft. fixtures with Grow-Bulbs.

[jamesgangnc]

It's probably too far away and too little light for any thing but starting stuff or house plants. Not full sun plants.

If you really want to grow crop style plants you need a ton of light. Look at metal halide and high pressure sodium lights. You need about

1000 watts per 4'x'4' space. I've seen a 1000 watt metal halide bulb held 6' p from a shadowed spot next to where full sun was shining. The full sun was still brighter.

[Jim Elbrecht]

Good point-- I raise the plants or lower the lights. [I use plain fluorescents just above the tips of the plants.]

These days I'm just over wintering Zone 10 plants in zone 5/6 in my basement.

Jim

[jamesgangnc]

If you are just keeping tropical alive over the winter that works.

I've looked at some green houses that one of the local research companies tests things with. They have a ton of those big round high pressure sodium fixtures in it. Like the ones you sometimes see in the ceiling of warehouse style stores. Except these are spaced about

4 times as dense and about 10' off the floor. Hate to see their electric bill.

[hrhofmann]

Sounds like you need sunglasses if you work there.

[HeyBub]

You will probably lose the civil suit.

The police lab, and a confirming analysis by the state narcotics bureau, will confirm that the submitted substance was high-grade Marijuana, formerly found only in the high Andes and represents a significant threat to the youth of the community.

[The Daring Dufas]

Yea, there was one crime lab run by an Affirmative Action scientist who would give law enforcement whatever analysis they wanted. I think the news story I watched about the whole cluster coitus told of people being sent to death row based on the manufactured test results. Amazing how many innocent people were hurt. A lot of stuff had to be redone at great expense. I'm trying to remember if it happened in North or South Carolina.

TDD

[Vic Smith]

My wife used standard shop lights in the basement to grow many plants from seeds. Kept them on 16 hours a day. They grew fine with no visible mutations.

--Vic

[HeyBub]

There's a presumption on your part that "innocent" people were hurt. The fact is, people go to jail, not for what they did but for what can be proven. Often what was done cannot be proven and what was proven was not what they did.

It is not an exaggeration that our prisons are full of "innocent" convicts. At least that's their story.

[krw]

Well, if they're trying to mimic normal sunlight, that would make sense. ;-)

[The Daring Dufas]

I know what malicious prosecution is and the importance of getting the right lawyer. I experienced it and the only person in my case to wind up in prison was the arrogant little creep who was the prosecutor. I discovered in person that law enforcement doesn't want to admit they're wrong and prosecutors will refuse to admit they're wrong in order to CYA. You can't sue them so the only thing to do is go to a much more powerful group with more and bigger guns to criminally prosecute them. If the little law man lies to the bigger law man, the little law man goes to prison. Of course any law man can lie to us lowly peasants.

TDD

[TimR]

I've always been a bit skeptical whether there's any added benefit worth the cost of the high priced grow lights.

I've used the recommended two cool white to one warm white ratio for growing plants with regular fluorescent tubes, it works fine.

I'd caution the OP to check whether his shop light can handle F40 tubes. We bought some shop lights where i work designed for 32 W bulbs, and they overheated badly on 40's.

[HeyBub]

The rule I quoted originated with Alan Dershowitz. Another of his rules is: "In virtually all criminal prosecutions, the defendant is, in fact, guilty."

I'm glad you were able to skin the system and get off (even if you were guilty).

[The Daring Dufas]

If they didn't know it was all a lie to start with, they knew it later and refused to take any action until I went to the FBI with it. It's amazing how the FBI can stir things up and get them to pay attention.

TDD

[Una]

I have now read up on the light emitted by various lighting systems and it seems to me there is little utility in using "tuned" growing lights. When efficiency is defined as some measure of photosynthetically useful light per dollar spent, most are less efficient than these fluorescents, except in the very long term. The very long lifespan of LCDs can be an important factor in some applications. My plan includes building a winter sun room with windows toward the equator, and people spend a lot of evenings in that room, so for me ordinary "white" fluorescents are a good choice. The question is do I want normal output or high output?

The lights will be used to overwinter tender plants, and start cuttings and seedlings. All the plants in question have survived many winters in the house with only ambient light but none of them are getting enough light for good health.

The fixture including bulbs came with the house. The 2 bulbs are 4 ft and marked F48T12CW Sylvania. Are these bulbs normal output (NO), high output (HO), or very high output (VHO)? "F48T12CW fluorescent" search results mostly refer to VHO bulbs. The cord on the fixture is very short and it is plugged into an outlet near the ceiling. So, no lowering the fixture closer to plants without an extension cord. Next step; take down the fixture to check out the ballast.

Una

[jamesgangnc]

I'd agree that you're not gaining much by using "grow" fluorescents verses regular warm ones. But as far as light per electric dollar the metal halide and high pressure sodium are not even in the same neigborhood as flourescent. Even a 70watt hps is blindingly brighter than a whole collection of fluorescents. If you shop around you can get hps grow light fixtures on adjustable hangers pretty reasonably. Sometimes I see them on craig's list as well. If you are in the construction business most parking lot and exterior commercial building lights are hps and work fine as grow lights.

[Una]

Like I said, what matters is the amount of photosynthetically usable light per dollar spent, over some duration. Dollar spent includes capital costs and operating costs. If I had to start from scratch, and I didn't work in the same room, I would not go with fluorescent lights. But in my case it makes economic sense to use the existing fixture, if it can be made to do the job.

Una

[Hell Toupee]

I'd use whatever you've got. There's not enough difference between the grow-tubes and standard tubes to justify the increased expense for a noncommercial operation. And I say that after running a greenhouse for nearly a decade.

The length of time the lights are on will have more effect than the type of tube or fixture used, as will the distance of the lights from the tops of the plants. Get the lights as close to the plants as you can (preferably around four inches), since light intensity drops off dramatically with distance. Hang them on chains or some other way to move them up and down as needed.

[jamesgangnc]

Or hang a shelf under the lights that you can move up and down.

[Vic Smith]

IME there's not much "capital cost" anyway to light a lot of plants. I set up 2 of the standard cheap screw-together metal shelving units, You can usually find then for less than $20 each.

8 2-bulb 4' shop lights which I got on sale for about $8 each. Bulbs run about a buck each. That'll light a couple hundred seed containers. She has 360 degree garden around the house. She was a greenhouse worker when she was a kid. Less grass for me to cut, but more turns.

But - I put 8 4'x11"x1/2" boards on the shelves because the shelves are only 3'. Think I had that lumber, but it's probably worth 20 bucks.

2 strip outlets, maybe 10 bucks. Anyway, that's 100-120 bucks done the cheap way for a lot of seedlings.

Cupholder hooks on the overhanging boards hang the lights on the chain that came with the lights. Think she adjusted height a few time a season - just move chain links on the hooks.

It's all sitting there 20 feet away, minus a couple shop lights I grabbed to replace bad ones elsewhere. Probably idle 5 years. She did it for 3 years, then stopped.

Seeds aren't cheap, especially "exotics,"and you get too many that won't sprout. There's timing issues with transplanting outside. Labor in planting and caring for seedlings. Biggest deal is bad seeds though. That pissed her off good. Got bad ones from different suppliers. Anyway, she can get robust plants at the garden centers pretty cheap and ready to go. And she likes to shop there. I never figured out the cost difference, but it's not tremendous.

So it's probably best to start small as you are doing. Me, I've just got more "stuff" sitting around until I figure what to do with it.

--Vic