Is this a mag deficiency?

This is my first grow and I'm on week 4. They are autoflowers.
I'm using a 70/30 coco perlite mix.
I drain to waste 1x a day until I get about ~12% run off or so.
I use jacks 20 20 20 and lotus cal mag (4-0-0). It's 11% cal and 3% mag.

Anyways my leaves started turning yellow last week, at the bottom. They've now started turning more yellow near the top. I have some burnt tips too and I noticed those before I noticed the yellow leaves.... that was the first thing that got me worried. The leaves on the bottom look worse now and one has a brown edge that's dying. My ph for the water I use is 5.9.

Any ideas?????

P.s. sorry the picture of the dying leaf was taken under an led, I took new pictures today but couldn't find it again.

That Jack's AP 20-20-20 fert is for live soil with microbes. All that urea is mostly unavailable to the plant. A good hydro nute is usually about four parts NO3 to one part NH4.

7CardBud said:

That Jack's AP 20-20-20 fert is for live soil with microbes. All that urea is mostly unavailable to the plant. A good hydro nute is usually about four parts NO3 to one part NH4.

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I didn't know they had one for soil.

Should I introduce another nit source? I'm assuming there's a liquid option.

Baystatestank said:

Should I introduce another nit source? I'm assuming there's a liquid option.

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I'm not a Hydro grower. But maybe switch to the normal Jacks or GH trio if you want liquid nutes. I have a feeling that urea is fucking shit up. Just a guess though.

Yeah it's looking like I'll go with 321 in the future. I'm stretching my dough right now so unfortunately I have to find a cheaper short term solution. Thanks for the help.

Baystatestank said:

Yeah it's looking like I'll go with 321 in the future. I'm stretching my dough right now so unfortunately I have to find a cheaper short term solution. Thanks for the help.

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@7CardBud might have a better option. He's a synthetic guy.

Or borrow @HydroKid239 's Leprechaun and maybe you can get some free stuff, .

There could be other issues as well that you need to dial in, like PPFD of the light, RH, Temps, salt lockout in the media...etc.
I just had two clones that looked just like your plants. After I moved them from the LEDs and put them closely under T5s, they greened right up.
The added heat the T5s produced upped the transpiration of the plants and corrected the issue.

Urea needs a couple weeks to be broken down by microbes. In coco you're adding a nute daily that has 50% of the N supplied as urea, that is mostly an unusable salt taking up PPMs sitting in your media. I know some people add microbe teas to coco, but that shit is usually expensive stuff.
If your own a budget, I think a solid hydro nute sould serve you best.

This should make about 120 gallons. If you opt for liquid.
Amazon.com : GH Flora Series' General Hydroponics 32oz Quarts Trio FloraMicro FloraGrow FloraBloom, 1 Set, (Many ##) : Patio, Lawn & Garden

This should make about 600 Gallons. If you want to scale grams.
Amazon.com : MASTERBLEND 4-18-38 Complete Combo Kit Fertilizer Bulk (12.5 Pound Kit) : Patio, Lawn & Garden

I've run masterblend before, it's solid and fairly priced per gallon.
They recommend 3,3,2 but I like the profile of 3,3,3. The extra epsom in coco is probably a good bet as well.

Here is the profile for a 150PPM Nitrogen solution. I use rainwater or RO so if you use tap or well your EC will be higher with more Ca,Mg.