Let there be light: lots and lots, all the time

First I did what they said. I used the SF recommended light schedule and dimmer settings and distance from the plants. When yield underwhelmed, I added nutes. Better, but not great.

Then I started pushing the dimmer settings, throwing a few extra photons in the mix. Plants responded by stretching until I ran out of adjustment for distance, yield a bit better, but I noticed my plants were never quite as plump as others. So I chased nute schedule and dosage, and went to giant, seven gallon pots, and the next pair started out ok, same as before, stretching seedlings wanting to fall over, and I’m thinking more thin plants.

So I just watered and ran my reduced dosage trio, and started some LST in the big fabric pots. Just about four weeks from sprout, and they’re lush and going great. In days I’ve been able to get nice LST going, and the leaf volume is incredible.

Then, crazy old stoner has a BFFO. about two weeks ago, or end of week two above ground, I wanted to check my plants early one morning, so I hit the bypass on the timer to light up the tent before the regular 6AM schedule. After watering, I went about my days, more watering, vigilant nutes according to my reduced dosage, and started LST, and never gave it another thought. Last might, after adjusting LST restraints, I thought “man, I’m getting this now”. Lush, healthy leaves galore, growing like crazy. Yeah, you dummy. They’ll do that when you run your light wide open, 24 on, at more or less the recommended distance. I’d forgotten about the bypass switch. I assumed the light was on 18/6. Miracle additive for plants, light!

Takeaways include, light sellers lie about power and energy savings. Yes, modern LED arrays are very energy efficient, but you still gotta put the electrons in to get photons out. The old school six hours rest was about cost for power versus yield. Your modern LED array runs cheap enough, time to yield and tent space become the limits, not power costs or heat from lights.

Plants, like people, crave what they don’t have. I do believe the sharp cut off of an 18/6 schedule encourages stretching by cutting light suddenly. The plant responds by reaching. Leave light on all the time , maybe less plant energy wasted on stretch, and more investment in the good stuff?

@Northcountryguy this all depends on the power of your light and the DLI.

Lower ppf lights are safe to run like that, but higher ppf lights can easily exceed the DLI threshold and start stunting the plants.

Light is good and cannabis likes a lot, but like they say too much of a good thing can be a bad thing.

I’ll keep that in mind if I start getting healthy looking plants that underperform. But honestly, as with the soil mixes that claim seed to weed capabilities, all in one, cool and cheap to operate become cult goals, like bikers chasing dyno numbers on a dresser, sometimes they sell us numbers because we buy them. But plants want light, and don’t pay the bill. As long as I’m not seeing sunburn or other distress, I think I’m in the fat part of the curve.


@Northcountryguy don’t forget too though that if you’re growing organic that rest time is actually essential. Cannabis exudes during dark time and the root exudates attract and feed the microbes that break down the nutrients for the plant.

No dark time means no microbes or soil life and usually equates to a runty or dead plant in a fully organic grow.

After some consideration, I restarted the timer, with a 21/3 schedule. Running the SF 1000 light, I’m not sweating the power bill. I’ll give ‘em all they want. But if a short nightly break is better than constant pounding, I’m fine with that. I do think the inadvertent 24 on schedule helped more lush, bushy veg than I’ve been seeing, and definitely running the light at 100 percent right from the start rather than follow the SF dimmer recommendations helped. (I had a mature plant in with seedlings for two weeks, so I had to run it high, then just adjusted distance but kept the light on 100% right from the start. A confluence of deviations from normal, and it seems to be working.

1 Like

21/3 wow!
When them gals gonna dream?

I had a crop of Autos that got stretched. It was due to wrong light heights.
I just got my Vivo and I set the height to 24 over.
About half way through veg I realized they were getting lanky. I posted an image on this site and Reed Daddy had me lower them. From there on out I keep them 10 to 12 over. I also maintain about a 20°tilt that I change sides on water days. Get deeper light penetration.
I brought them to harvest. They never recovered. One grew more like a vine. It would have laid on the floor of I had not propped it up.

I start and stop my lights with a 2 hour margin at 70% to mimic sun rising and setting. Be really cool to have dinner kind of Lazy-Suzie that would rotate once an hour. Tilt your lights to 23° and you got planet earth and Sun in your tent.
I’ll harvest my photo Banners next week. They are monsters.

I honestly don’t know what to think. Autos are a freak of nature as it is, they’re bred to ignore their natural photo sensing, in favor of genetic flip. I understand why that worked for rudalis to begin with, essentially round the clock summer sun in Siberian summer, much like our Alaskan venues where they raise thousand pound pumpkins. We take that rudalis genetics and apply it in artificially lit and fed situations as if light no longer matters except as fuel supply.

I think that’s only half the story. When they go vine batshit, a thirty inch strain pops forty, the main cola trying to deep throat a light that’s at max height, it’s not because they’re happy, and it’s diverted a shit ton of resources into twigs.

Give me a lush, happy little bush that fruits like crazy, and isn’t stretching because it’s getting plenty of light, I think that’s more like what an auto is genetically wired for.


@Northcountryguy I tend to agree with you. Too much of a good thing can be bad, which is why I like the 18/6 schedule. My COB led light only has a veg switch and a bloom switch, no % intensity, either they are on or off. Like in the old days when I grew under 1000w metal halides, it was on or off. So when things are on, they are ON! Full power Scotty!

Whenever I tend to my garden, I try and pretend I’m a plant and what would I like as a plant? Light, lots of it! You don’t see too many people lying on the docks suntanning first thing in the morning or evening, only when the sun is high above and strong. Once I’ve had my 18-hours of rays, lemme sleep for 6!

1 Like

I still use them lights @spudgunner i love them i have 3 four hundred metal halides