Germination and lighting question about autoflowers

From a fellow grower: I am brand new to AutoFlower seeds, I have a Supercloset grow box, with a germination/heat pad- Can you give me advice on the germination process/lighting, and lighting for the grow with Autoflower seeds? Do I use the Cool then Warm lights that I have for Vegetation/Flower phase or just one light throughout? Do I use 18 hour on/6 off for Veg, 12/12 for Flower

Germinate the seeds by placing them into a small cup of tap water in the dark for 24hrs. If you have hydrogen peroxide then you can do a 50/50 mix instead of just water for better oxygen but it’s not necessary. After the 24hrs is up the seeds should be cracking open and some may even have a tap root sticking out. Transfer the seeds to a damp paper towel inside a ziploc bag(do not close the bag) for another 18 to 24 hours. The temperature should be around 75 to 80 degrees for the best results. Once the seeds have at least a 1/4 inch tap root they can be placed into the grow container/medium your using about an inch into the medium. Cover the top with a clear dome of some sort to keep the humidity up. Brand new seedlings get all their water intake from the air until they establish a root zone. Make sure not to over water them during their first week.

Lighting an autoflower can be whatever you want as they decide when they want to flower. I would recommend an 18/6 light schedule during the vegetative period and a 12/12 schedule for the flowering period. The light should be around 18 to 24 inches above the plants during veg and around 12 to 15 inches during flower.


Thank you for the great advice!

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Hi again, sorry, few clarifying questions:

  • I have a germination kit i bought with my grow box from Supercloset- a tray, rock wool cubes, dome, and heating pad- Would you recommend your method instead?
  • I have not heard the hydrogen peroxide addition, makes sense
    -After they sprout, and I put them in the dome, should I immediately turn the lighting on, or wait a few days? How about the circulation fan and filter?

My apologies for the basic questions, I’m a total rookie, probably over thinking, but I don’t want to screw it up!

Thank you!

If you don’t click the arrow to the bottom right of a post the person posting it may not notice your post which is probably why you haven’t received a reply to your question. Most members are really good getting back to eager growers.

I wouldn’t use the rock wool if you are growing in soil or coco, it just gets in the way. Rock wool would be a preferred method for hydroponic grow.

The heat mat is important to get the seeds germinated, use it under the cup of water and with your seedlings until they get established.

Use a humidity dome until the seedling pop up, then you can remove it several hours a day. After they have been up 2-3 days the humidity dome shouldn’t be needed.

You can wait a day or two to turn the lights on, I turn them on right away for the heat. Fan won’t be needed until they are up and established, charcoal filter isn’t needed until they begin to stink, usually in flower.

Thank you!

I should’ve clarified, I am using hydroponics, the grow box I bought has hydroponics, and small baskets to transfer the rock wool cubes to, after they germinate.

Do you recommend the cup of water method for germination, rather than the rock wool method, even if I’m using hyrdoponic? Do you have an opinion on the suggestion to add hydrogen peroxide to the germination water?

Thanks for your help! I’m afraid I’m going to screw it up from the start!

This is the germination ‘kit’ I bought with my Supercloset grow box.

Supercloset Total Germination Package.

I don’t typically use rock wool, but from what I know you need to “prepare” it by soaking it with water and from what I can tell, some mild nutrient. I think HDI (Hydrodynamics international) is a company that makes rock wool and their website should explain how to prepare it.

Once the rock wool is prepared you put can put the seed directly in the rock wool, or if you want, you can germinate as suggested above and place the seed with tap root into the rock wool. If you are doing more then one plant you might want to try it both ways to see what works best for you.

I did 18/6 whole time last run this run I’m doing 20/4 i don’t recommend changing to 12/12 nor do breeders recommend for autos good luck

Just a fyi if you do not have a thermostat controller you’re heat mat will run at full power and WILL exceed that 80°F temperature so just keep an eye of the mat so that you don’t cook you’re seeds also you can pick up a controller on Amazon for around 30$

Thank again, I appreciate your advice, and taking the time to help!

Thank you, excellent advice, I was hoping someone had experience with autos, as this is my first try with autos.

Thank you!!

One other thing I’d like to mention about using rock wool to germinate your seeds… make sure you enlarge the hole in the rock wool. I’ve had seeds fail because the tap root ends up on top and the new growth has problems growing past the seed husk blocking its way.

Ah, good to know! It does have a controller, not sure how accurate or reliable it is, I’ll keep an eye on it.

Thank you very much!

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Excellent advice, that makes perfect sense, will do!

Thanks again, much appreciated!