When to start fertilization?

Hey awesome grow community! I have 8 new sweethearts and have them in Fox Farm Happy Frog soil. They are about 2 weeks post sprouting and one is a monster so it’s in a fabric bag. All they have ever had is distilled water, to this day. I have a 5’ x 4’ x 6’ grow room (6’ height) with 360 CFM exhaust fan and have 2 SANSI 36w LED (170w equivalent) and one 300w Canagrow COB LED in the middle.



Quick Learner

Rest of Harem all about like this

When to fertilize? What NPK, very low I assume? When to switch to Fox Farm Grow Big 6.4.4? Thank you all in advance!

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Not for awhile, ffhf has tons of nutrients, I didn’t start till week 5/6, careful not to over water

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First Welcome to the community I think your seedlings look nice and healthy.As @Tinman mentioned be careful about over-watering the seedlings. Try to water in a round 6 inch pattern away from the plant. Good luck.

All they’ll need for the first 2-3 weeks is water. Since you’re using distilled water keep an eye out for calcium or magnesium deficiencies.

With happy frog you could start with low doses of nutes around week 4-5. If you don’t have a pH meter, get one asap.

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Thanks all. Right now I spray distilled water around base of plants twice a day. Then they go into a propagater at night with heated pad and lid on. So it seems like I should wait a couple more weeks. Will look for cal/mag deficiency.

I would look into investing in another light, I don’t think that will be adequate coverage for flowering that many plants.
Quantum boards are always a good option. You’ll need 4 minimum in that space. 5x4 isn’t real common. 2 Quantum board 120’s in the middle of the 4 panels would give adequate coverage. dbrn32 Is the guy to ask if you have lighting questions.

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@dbrn32 can you check my lighting further up in this post? I only plan on small batch 2-3 plants at a time. Thanks @Covertgrower for the tip on lights!

I agree you are probably under powered for space that big. 20 square feet is a big grow space. Even if you don’t use all of it you will have light going to places other than plant canopy.


So I use 12” of the edge of the floor for some equipment and grow in the remaining 4 x 4’ space. Will a Quantum light board be adequate for this space?

Two of these will be good for a 4’x4’ space.

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It’s best to remove as much equipment as possible from the tent. Humidification, and dehumidification should be taking place outside of the tent. Keeps heat out of there. Except the exhaust fan obviously. @The_Analogkid