When in the Seedling stage, you want the light to be around 2.5-3 feet above the tops of your plants. Most LED manufactures state their rated watts in the name of the unit and this can be up to double the actual used watts. Thankfully, adding a grow light is super easy. Seedlings I’m larger pots take forever to show signs of growth because they are in larger pots, so the waiting game sucks. - posted in Cannabis Propagation: Hi all, I have 5 SLH feminised seedlings in 1.5 litre coco, theyre about 3 days old, and I have them under a small CFL lamp but theyre really reaching for the light. I've since lowered the light to … Your grow lights should be turned on (or your seedlings should be put under lights) as soon as the first seed starts to sprout. Not Considering the Other Factors. It's just more about what you want to do. Like you, when I just started indoor seed starting, I also had a lot of questions to ask, like 'when do I put my seedlings under light' or “how far my seeds should be from the LED”. Seedlings I’m larger pots take forever to show signs of growth because they are in larger pots, so the waiting game sucks. Should I keep the light on now? The most common mistakes with LEDs are not having enough light and not placing the light at the proper distance.If you do not provide enough light, your plants will not grow to their full potential. The natural light from a window is not going to cut it! LED grow lights are a great aid when growing plants indoors but by themselves they cannot do much. For seedlings you can get away with lower wattage or have the light at a good distance away. Q: Last spring I had lots of luck starting seed of coleus, impatiens, zinnias, marigolds, and vinca with just one fluorescent light.I want to add more this year, and I'd like to know which lights are best. Impatiens grown after germination under blue (B), green (G) and red (R) LEDs or fluorescent lamps (FL). I was wondering when do put seedlings under the light? It's just not a big deal one way or another when the little lady is so small. And yes, as the dude above said, you can of course switch to your LED. It can't use all that light when it's a little seedling anyway. I started ... 72 plants per tray – because I plan to plant out these cold season plants under row covers or in the greenhouse as soon as they are big enough to handle. “When can cannabis seedlings be put under lights or in the sun?” is a common and sensible question that is often asked by novice cannabis enthusiasts after germinating seeds indoors under lights.. For those who are growing indoors, cannabis seedlings may be put under lights as soon as they emerge from the soil or growing medium.. How much light for cannabis seedlings? Add a simple timer, which will turn the light on and off automatically, to make a simple but effective growing system. I know that LED's can burn seedlings even though they don't put out a lot of heat, so I started out at 56" as per the manfacturers recommendations but quickly realized that's way too far after some reading on here so that only lasted a day. If not when is the best time to do it please. Figure 1. Takeaway: Grow lights are a great tool for making the growing process more efficient, but they can also be harmful to the plant if not used correctly. The light is just over 2 foot above the seedlings. When can I put seedlings under the big light? I know that LED's can burn seedlings even though they don't put out a lot of heat, so I started out at 56" as per the manfacturers recommendations but quickly realized that's way too far after some reading on here so that only lasted a day. My 2 foot 4-bulb fluorescent grow light will arrive tomorrow and I’ll put that over my seedlings instead. When Do I Put My Seedlings Under Light? How to Use LED Grow Lights 2019. as long as there is no darkness interval between putting them under different lights, and there is still the reccomended dark period, this should be fine. Seedlings need more light than full grown plants, ideally as much as 16-18 hours a day. Also, if the seedling is still crooked do i wait to put them under the lights or can I just place them under? Once you are in Vegetation, you can lower the LEDs to be around 2-2.5 feet above the tops of the plants. A simple test you can always use to tell if you are too close is hold your hand under the lights … And that's actual wattage used. I start my seedlings under a 400w mh from the time they break soil, I place the light at 18" above and have done that for nearly 15 years now with amazing results, that being said I'm not to familiar with led so i suppose shouldn't suggest what I'm not familiar with.