Supplement with sunlight?

I was wondering how much of a difference it can make if I am able to take my plants outdoor for a few hours a day (3-8 hrs a few days a week)? Would this have a noticeable affect and could it have a negative affect due to returning to a lower amount of light for the rest of the time (flowering or Vegging matter?).


Not sure I can make it happen every day or a set number of hours but I'm thinking on the days I can setting them outside in the natural sunlight for a few hours a day could only help and I could turn off the lights for a few hours save on the electric bill a little.

Depends on your indoor lights. It's entirely possible that your grow lights are providing the plants more light than the sun can, in which case bringing them into the sunlight would actually lower the amount of (plant-usable) light they are getting.

Well, I kinda doubt that I am gonna have this problem as flowering is under 400w and veg is 250w.... sorry probably should have mentioned this.

i would love to know the answer to your question because i do the exact process your talking about i think it does work my plant seems plenty healthy

If you have a decent bulb, and you are hitting 5000 lumens per square foot, then your light is almost definitely better for the plant than sunlight. There've been some discussions about this. Around 7-10 thousand lumens per square foot is midday sunlight at the equator. But raw equatorial sunlight is not plant-optimized like good bulbs are, so most of that light is actually not used by the plants. With a horticultural bulb, a much higher percentage of that light is plant-usable.

If you have your 400 watt light over an area of 3' x 3', the bulk of your plants will be better off under the light. The plants at the edges, farthest from the bulb, they might do better with sunlight. With your 250, probably all those plants would be better off under the sun, unless you have it very close to the plants (which can obviously cause other probs, like frying them).

Assuming your 400 watt bulb is on 12/12 and you pay $0.20 per kilowatt hour, taking them outside every single time, and never running your light at all, would save you about $29 per month. So about 50 cents every time you cart them in or out. Adjust accordingly if your electricity rate is higher or lower.

Hope that helps!

What do you think about a 50 watt HPS along with 3-42watt and 1-14 watt warm light cfl's over the top and 5-14watt warm light cfl's around the sides with mylar. The top lights are within 2-3 inches of the plant. The HPS had one of those clear covers on it which absorbs most of the heat

im sorry also my space is 2x2x4 and plant is currently 21 inches 2.5 weeks into flower

Bongulator said:

If you have a decent bulb, and you are hitting 5000 lumens per square foot, then your light is almost definitely better for the plant than sunlight. There've been some discussions about this. Around 7-10 thousand lumens per square foot is midday sunlight at the equator. But raw equatorial sunlight is not plant-optimized like good bulbs are, so most of that light is actually not used by the plants. With a horticultural bulb, a much higher percentage of that light is plant-usable.

If you have your 400 watt light over an area of 3' x 3', the bulk of your plants will be better off under the light. The plants at the edges, farthest from the bulb, they might do better with sunlight. With your 250, probably all those plants would be better off under the sun, unless you have it very close to the plants (which can obviously cause other probs, like frying them).

Assuming your 400 watt bulb is on 12/12 and you pay $0.20 per kilowatt hour, taking them outside every single time, and never running your light at all, would save you about $29 per month. So about 50 cents every time you cart them in or out. Adjust accordingly if your electricity rate is higher or lower.

Hope that helps!

Click to expand...

Wait, what? Sunlight isn't as good as lamps? Las time I checked, plants evolved for billions of years to use sunlight, not grow lamps.

Sure, sunlight is good for plants. But grow lights can provide more plant-usable light. Nothing says we can't improve on nature, and in this case, we have. Except that grow lights do cost money to operate and the sun is free. That's one area we can't really improve on sunlight: cost.

Basically, you're saying that because the sun's been around billions of years, it's best at anything light-related. Welp, it ain't so. There are lots of light-related things we can do now that the sun can't do at all. Like cutting through sheet metal, LASIK eye surgery, nano-cleaning of rare paintings, storage of data via optics and so on. Including creating bulbs that dish out more PAR light than the sun does, at least with the sun 93 million miles away and the grow light a few feet away.

A simple demonstration of our power over light can be found in any tanning salon. Wait for a bright, hot day. Bask in the sun for an hour with your shirt off. Then go into the biggest, baddest tanning booth the place has and set it on its highest setting and wait an hour. If you're still alive, you will be waaaaay more burned from the tanning booth. They actually have controls on some of them so you can't kill yourself, like a governor on cars, but for light intensity. And they could easily make them even brighter; they just don't want to kill their customers (too quickly).

Bongulater what about the light i have compared to the sun

I put mine outside from around 10 til around 5 everyday (unless it's shitty out) and they seem to love it. When I take them out the leaves look sort of flat, at the end of the day when I bring them in the leaves are pointing up toward the sun.

I'm using 6500K daylight CFL's keeping them about and inch away from the plants.
IMO there's no substitute for the sun when it comes to growing things.

You got me, hendry. CFLs are so variable. And distance matters hugely. Light intensity decreases with the *square* of the distance, so an object 10 inches from a bulb receives only 1 percent (1/(10^2)) of the light that an object one inch away would receive. When the lights are small, like CFLs, even an inch can make a big difference. And then you have multiple CFLs *and* a small HPS. Just too complicated. Get a light meter!

thanks for the advice i really dont know where to easily get a light meter, but would you say with all those varibles i have it would be best to just put it in the sun everyday then.

Thanks for all the replies, one more Q, I kinda figured with the 250w they would be better off, but I was wondering since they are on a 18/6 schedule and they would be getting like 4-8 hours of bright sunlight then 10-14 hours of a lower level light if this would have negative affects like stretching, sun bleaching, ect... Just anything in general that I should be looking out for?

Did it for the first time today, they seemed to like it.