Yellowing in early flower after flush and synthetic nute switch

Hi again guys, back with the regenerated sour diesal auto that I topped by accident, it has come back with a vengeance and stand 6-7" taller than the same sour diesal seed that I planted at the same time.

I noticed some deficiencies in this one right after it began flowering and just got a bottle of sledgehammer so I decided to flush the soil and then switch the plant into my liquid nutes from Fox farms (tiger bloom and cal/mag).

After the flush I gave another feeding (3 Tsp tiger bloom - 1 Tsp cal/mag - 1 gallon water pH’d after mixing) with the synthetic nutes so there wouldn’t be lost grow time, after the switch I’m seeing some more yellowing of the lower leaves which looks like potassium deficiency but I know at this point that I don’t know anything so throwing it out there for advice before I do something to make it worse… I was thinking of doing another nutrient feeding this week instead of just plain water but again, don’t want to add fire to fire.

Any advice, as always is greatly appreciated!

@imSICKkid @MattyBear @Covertgrower @beardless

1 Like

Follow the feed guide and give it a full feeding with 20% run off. Also use the tds meter so your able to insure your mix is not to much or to little ppm

Ps did you say you cut a clone from a auto diesel? And this has grown into a full plant?


Thank you, I will do a Ppm test later today to see where the soil is at, I think it went from 1500+ to 600 after the sledgehammer flush, are you suggesting there is a build-up that I need to flush properly? As in, too much nutrients instead of too little?

If the Ppm is too high where should I aim to get it to with another flush? then after that I would immediately do a full Nute feeding or wait until the next feeding date?

No this wasn’t a clone (grew from fem auto seeds) but I snapped the main stem when trying LST right near the beginning to the point where it had only one leaf left, and it regrew surprisingly and I have done LST to it since and it seemed to be thriving until this yellowing, and it’s been good to compare to the other plant I planted at the same tine with the same seeds that is about 2-3 weeks from harvest - here is what I snapped it to before it started regrowing:


If your growing in soil learn to do a soil slurry test (YouTube) with distilled water.

If your using fox farms ensure your following the correct ppm scale. This below as been adjusted for most of the tds meters we have.

If your having issues the easiest thing to do is to do a full flush until your ppm is like 400 and then give a full feed (checking that feed with a tds and ph meter before giving) if it’s to high of ppm dilute it with water if it’s not enough add more nutrients. When ppm is right PH it to 6.5 for soil.


You’re a hero, you just mentioned so many things that I knew about but overlooked like checking the TDS of the solution before feeding and somehow I’ve never come across that fox farms chart before so I need to study that.

I’m going to go and study the soil test with distilled water that you mentioned too as I just picked up a jug of distilled water yesterday.

I’ve got my first tent arriving tomorrow and will be moving on to my first photoperiod grows, loving this forum and the support so far, I wouldn’t know half of this stuff with it!

Thanks again!


No sweat, it’s a modified chart you won’t see it anywhere all the other fox farm ones are on the 700 scale I belive and this one is the 500 scale.
Download it print it and laminate it for your grow room or save it in a gallery on your phone to reference all the time.
Also get a VPD cannabis chart and do the same thing.

Don’t water with distilled water, use tap water just save the distilled for testing. Oh and make sure you add a carbon filter to your tap water line or let it sit out for 24hr for chlorine to evaporate before you feed it to your plants or animals.


Do you also have the grow big and big bloom? The 3 are designed to be used together. You could probably get by for a bit using in conjunction with calmag, but I think would eventually be problems. Perhaps not helping in your current situation.

1 Like

There’s my second mistake it seems… I’ve been using tiger bloom only with the cal/mag as I read somewhere that is for when it is flowering, I didn’t think that the other 2 were needed also… That means my other plant that almost at harvest has been under-fed as well

1 Like

Well I wouldn’t have said you underfed as much as maybe not having the ideal cocktail for them. You seem to be doing alright, so not worth being super critical over.

Well I might just grab some Big Bloom as well then as it’s around week 5 of flowering so as per the chart above I wouldn’t need Grow Big.

This has all been eye opening and I will have to rethink my nutrient and medium for my next grow I think, I’ve heard that Gaia Green Organics are good.

1 Like

I don’t grow with organics anymore and the products I used prior weren’t the most user friendly. So probably bit the best to provide feedback on how current products are.

No worries I appreciate your advice regardless, I did a slurry test as per @Nicky advice and the Ppm was at 275 and the pH at 7.1 when the water was pH’d to 6.6 before the slurry test.

It seems the soil is raising the pH, is this solved with a flush using pH’d water? I have sledgehammer too if that would help but not sure if that affects the pH much.

I also have Big Bloom arriving today so I can give them the full recommended feeding range once I figure out what to do about the soil.

Here is the PPM 700 scale.

1 Like

What would be the difference between this and the 500 scale? Very new to all of this but thanks for sharing

@Dxbbred No clue in the difference to be honest. The chart I posted came in the FF Dirty Dozen box. I guess my PPM meter is 700 as the PPM is pretty spot on with the readings I get.

This comes from Blue Lab which makes good meters. This is the difference. :+1::+1::+1:

1 Like

That’s really helpful thanks, I need to go figure out which tds meter I have now then…

1 Like

Here is a 500 PPM that @MidwestGuy had posted. the only difference I can see is in PPM. I believe most of the PPM meters sold on Amazon use the 500 meter. Hope helps you.

@Dxbbred @MrPeat

1 Like

Sorry @Dxbbred I just noticed That @Nicky posted the same one. Think I’ll have another bowl LOL.


It really does because most TDS meters don’t state what scale they are using which is weird, I will go with the 500 scale for now and purchase a Bluelab TDS meter next so that I don’t have to worry as they do both scales.

If anyone has any advice about the pH raising from 6.5 to 7.1 in the slurry test that would answer all my issues right now. I’m thinking another pH flush before a full nutrient feeding (also pH’d and Ppm tested) but if I’m missing anything, let me know!

Thank you!

I don’t mind any crossover information, that fact that you guys are willing to lend advice is amazing in itself, I love this community