Lighting Question

New to the forum so sorry if this has been asked before. I sprouted my beans using the water and peroxide soak, moist paper towel in the dark. All beans sprouted. I moved them to my rockwool cubes yesterday morning and put them in my grow cabinet. They are very young and tender as you can understand. When should I begin to start my light cycle and what hours of light should I be using. I have read about sprouts stretching toward the lights and am trying to avoid this. Any advice is greatly appreciated. Thanks


@Gar Welcome to the forum!!!

What kind of beans are they? Auto, Feminized or Regular?

Not that it really matters I suppose in seedling stage.

As far as the cycle, most here would say you can start with 18/6 cycle but some use 20/4 or even always on for the first week or two. Really just a matter of your preference and additional cost to run lights longer.

As far as intensity, it depends on your light. In all stages your intensity should be dialed in to what that stage needs in terms of PPFD or PAR. Most light makers include a chart to tell you how far to place your light above the plant at each stage of growth. This height will vary between manufacturers and even from model to model even though they may look the same.

If your light is dimmable you can adjust the dimness to achieve different PAR at same height. The manual should recommend settings as well if the light has this feature.

If you don’t have the manual I would suggest downloading an app named Photone. It is a light meter that is easy to use to test the intensity of your light. You just choose the type of light you are testing and what units you want to test. I test PPFD. You have to pay for access to some features but the value it can bring to knowing whats going on with your grow far outweigh the minimal expense of the app.

In general the intensity you want in PPFD is:

200-300 in seedling stage
300-600 in vegetive stage
600-900+ in flower stage

If your intensity is dialed in during the seedling stage it should minimize any unwanted stretch.

I can’t stress enough how important keeping a check on the lights makes for best possible outcome.

Good luck with your grow!!!

The beans are Autos. I am currently running a Kind LED light that came with the cabinet and it does not have any way to adjust the light output. I did set the timer for a 20/4 cycle. Would like to move that to a 18/6 in a couple of weeks.

I appreciate the info and knowledge.

If ya growing autos there is no reason to go 18/6. I cut my autos to like 21/3. They need to be growing as much as possible… My experience has been keeping the light close keeps them from so much stretching. :sparkles: This is my White Widow auto born on July 1st. Abo

ut 7wks old.

Here is another that quit eating and just kept getting taller. Same seeds same nutrients . It juss happens