I will be planting my tomato and pepper starts soon. Last year I had them under the grow lights at night and off during the day. This didn’t seem to cause any issues for me but I read a lot of people saying that it isn’t good to do this. Thoughts?
by SunshineFloofs
11 Comments
I have mine on for 14 hours starting at 630
Can’t imagine any reason why plants would care what time it is, even if they experience one super long day when you move them outside. Some plants need a certain amount of dark for various hormonal reasons, but not tomato or pepper.
This just keeps them a little warmer at night when you’re likely to have the heat lower.
I don’t worry too much about light timing. Shit I’m running 24/7 now because the house is unheated. I need the lights to bump my temp up to a reasonable range. Coincidentally my tomatoes and peppers are going nuts with growth. They’re all dwarfs so I’m fine with it. When the cold passes I’ll go back to 18/6 or 16/8 or so.
It doesn’t have any meaningful impact as long as they get a light and dark cycle. Plants do require a period of darkness though. Doesn’t matter when you do each
Nightshades don’t care about day length. They just don’t gain additional benefit past ~16 hours, so you’d just be running lights for no benefit, wasting electricity.
It won’t hurt them, but it’s also not really helping. Tomatoes and peppers don’t need light at night, they actually benefit from a **dark period** to rest, just like they would outdoors. Leaving grow lights on at night won’t usually cause problems short-term, which is why your plants were fine, but over time it can stress them and lead to weaker growth. A better setup is lights on during the day for about **14-16 hours**, then off at night.
This vid shed some light on grow lights
https://youtu.be/79lAUJH-2hE?si=Gl2j9KK1HN-R7Gec
Electricity costs more in the evening than during the day, so having them on when it’s cheaper would be better. Otherwise, they don’t know what time it is.
I keep my grow lights in 24/7 and get incredibly healthy seedlings…after the plants are sturdy enough I move them outside for real sunlight, then back under lights at sundown. Lights are lowered to almost touch the leaves at every stage.
What zone are you in? I’m in 6A and don’t plan on starting Chiles for another 5 weeks.
As for the light, you should give them a natural dark cycle with the light.
I intentionally run my indoor grow lights mostly during non-peak electric utility usage hours. In some cases, you might get lower rates per kwh from your electric utility.
Also, plants know light, but they don’t know the difference between 12am and 12pm and don’t care.