LED Panel distance and intensity

[herrjack24]

Hello! I was wondering if any of you by chance used to grow cannabis using a Spider Farmer SF 2000 - 200W LED panel or something similar because it's the first time using LED panel and the plant grow 7cm (2.7") tall in just 3 days since she break the soil.
As far as i know the plant stretches if it does not have enough light. But i respected Spider Farmer guidelines, and still the plant it's already 7cm which i consider it a major stretch.
It's my first time using LED's and i didn't knew what to expect. I was afraid not to burn the plant so i followed Spider Farmer growing tips. It says the distance must be at 24" - 30" at 50% intensity.
Can you tell me your experience using LED, distance, intensity etc

Thanks

 

[Chasev89]

Hello! I was wondering if any of you by chance used to grow cannabis using a Spider Farmer SF 2000 - 200W LED panel or something similar because it's the first time using LED panel and the plant grow 7cm (2.7") tall in just 3 days since she break the soil.
As far as i know the plant stretches if it does not have enough light. But i respected Spider Farmer guidelines, and still the plant it's already 7cm which i consider it a major stretch.
It's my first time using LED's and i didn't knew what to expect. I was afraid not to burn the plant so i followed Spider Farmer growing tips. It says the distance must be at 24" - 30" at 50% intensity.
Can you tell me your experience using LED, distance, intensity etc

Hello, my first grow kit was from spider farmer . I had the sf1000 though. In general you can start with your dimmer around 70% at 14” or so and work the % up as the grow advances. You’ll want to be at %100 for flower. The spider farmer set was great to start. I do love my new Vivosun stuff a bit more though. Hope you have a good day buddy.

 

[Delps8]

Hello! I was wondering if any of you by chance used to grow cannabis using a Spider Farmer SF 2000 - 200W LED panel or something similar because it's the first time using LED panel and the plant grow 7cm (2.7") tall in just 3 days since she break the soil.
As far as i know the plant stretches if it does not have enough light. But i respected Spider Farmer guidelines, and still the plant it's already 7cm which i consider it a major stretch.
It's my first time using LED's and i didn't knew what to expect. I was afraid not to burn the plant so i followed Spider Farmer growing tips. It says the distance must be at 24" - 30" at 50% intensity.
Can you tell me your experience using LED, distance, intensity etc

Thanks

The recommendations for lighting for the SF2000 are here:

and the PPFD map is here:

Below is the light data from my most recent grow.

For the first few days after germination, the light was at 100µmol but, after day 4, was at >=300µmol

Spider's advice of 24-30" and 50% will work fine because that's very little light and that's all that plants need in germination.

Unfortunately, they don't have a PPFD map for 24" but rough math and an educated guess tell me that they're pretty much in line with the PPFD values I use.

If you look at the PPFD maps at 12", 16", and 18", my thinking is that at 24" the light will be putting out about 600µmol so 50-75% of that will be 300-450. The 450's a bit high for a young seedling but that's where you'd want to be at 21 days.

You're wise to be concerned about stretch. I've been an active participant here and on another site for >3 years now and my opinion is that growers lose far more yield by not giving their plants enough light than they do by giving them too much light.

That's not a stretch (pardon the pun) because it's very hard to damage a plant by giving it too much light. It's negligent. On the other hand, it's easy to not give cannabis much light — it will still grow well and look nice — but the grower ends up with perhaps 50% of the crop they could have had if they had fed their plants well.

My preference would be to avoid the 24" hang height all together. Per the post by @Chasev89,if you go off of a PPFD map, it's easy to set the dimmer % to get you in the ball park for PPFD. I can do the guesswork from a PPFD map because I've spent a lot of time learning about grow lighting but it's easier to work from the 18" map and set the dimmer to about 30 or 35%.

The biggest issue and I hit this even though I use a $600 PAR meter daily, is to watch the plants. We can measure how much light is falling on a plant but only the plant can tell us how much light it can use.

The biggest sign that your plants are getting too much light is that they will curl up their edges ("canoeing" or "tacoing") or they're turn the leaf vertical, like a Venetian blind. If that happens, raise the light a couple of inches. The leaves will uncurl and, after the plant has grown a for a couple of days, try lowering the light again.