When to Add Nutes to FFOF?

[GalaxysEdge]

I started my grow in solo cups using Fox Farms Ocean Forest soil. I transplanted to 3gal containers two days ago which will be their final pot. My question is...

How will I know when to add nutrients to the soil?

I've read that it takes generally about 20 or 30 days to use up whats already in the soil. Do I start taking PPM readings around then? What PPM am I looking for to let me know that I need to start adding nutrients?

Thanks all!

 

[mysticepipedon]

I'd say that's about right.

What I've noticed during my current grow is that under LEDs, the plants will show deficiencies, particularly with Mg, but also the other macro nutes, right after you flip if they don't have the right nutrition. Then they show light stress a lot more.

I'm running 4 clones of the same LED-sensitive plant. One got a store-bought mix called Coast of Maine, the other three got FFOF. CoM is twice the price and I've never heard of it before, but I figured this was for weed bro science, so the expenditure was worth it.

The CoM plant is a darker green, two of the other three FFOF plants show Mg deficiency, the third is a light green, just a hair away from showing a deficiency. Now, the CoM plant is doing fine, while the other three show light stress.

So, bottom line, at around 20 days, I'd supplement with some epsom salts dissolved in your water and keep them on veg nutes for at least a week into flower, if you're using LEDs.