5.8 to 6.2 in soil?

[Sctanley007]

Setup is a 2x4 with MH TSL2000. Growing in HF soil with 4 & 5 gallon pots.

Began growing autos on November 1 and have been using Jack’s Tap line. I’ve been getting guidance from their customer service lead to get their regimen down. So far the plants are growing great and the buds all look outstanding. However I’ve got leaves going yellow and showing signs of deficiencies.

The two on the right are at 66 days. Rear right Seemango, right front is critical xl. Back center and left are gnomo’s which sprouted November 5. The two in front are 21 days today.

Previously I just used Jack’s classic 20-20-20 with silica and CM+ and never saw anything but perfect leaves. I’m seeing yellowing and rust as well as a few spots.

Im watering until runoff but not as much as I use to with photos. I was thinking perhaps a lockout. But doesn’t make sense with several plants.

The rep is adamant that the solution be ph’d to 5.8 to 6.2even though I’m in dirt. I’ve always read those numbers are for hydro not soil. I’m thinking the plants aren’t getting everything they need at that percentage. I’m thinking about bumping up the ph to 6.5 as I’ve done for years and see if the situation fixes itself.

Any thoughts?

ps- I do realize the Seemango is at the recommended harvest so she’s looking nicely beaten up.

 

[Lime]

6.5 for soil.
5.8-6.2 is for coco or hydro

 

[Weaselcracker]

In soil it shouldn’t make any difference whether you feed at 5.8, 4.8, 7.8, or whatever. The soil should buffer it (usually to around 6.8) within minutes.

Try a slurry test if you’re in doubt. It only takes minutes for my promix to balance out almost any solution I throw at it.

 

[Bill284]

In soil it shouldn’t make any difference whether you feed at 5.8, 4.8, 7.8, or whatever. The soil should buffer it (usually to around 6.8) within minutes.

Try a slurry test if you’re in doubt. It only takes minutes for my promix to balance out almost any solution I throw at it.

Is it possible that soil is depleted.How long have they been in there.

 

[Emilya Green]

The rep is trying to help you, knowing that your soil has a strong upward drift, with its base pH being set to 6.8 or so. Knowing this, by pH adjusting your fluids to the low end of the soil pH range of 6.2-6.8, you can take advantage of this drift that is set into your soil. 6.2 is actually a very appropriate pH to adjust to in FF soils, because of their strong upward drift, and if you don't come in at the low end, no higher than 6.3 pH, you will tend to get heavy metal deficiencies in your last third of bloom as those deficiencies continue to build. If you constantly adjust your pH to 6.5 in FF soil, you can pretty much assure yourself of these problems, because your nutes never get to see the low end of 6.2-6.5, where those nutes are the most mobile.

6.3 pH is the point where mathematically the most nutes are the most mobile in soil. For this reason, 6.3 for years was the most commonly advised pH to adjust to. 6.5 is exactly in the middle of the range, and in some soils that works just fine... for a while... but 6.5 adjusters are always having problems and coming here for help and for over 10 years I have been giving the same advice I am giving you here. Adjusting to the correct pH is super important in some soils and with some water... other people seem to be able to get by with absolutely no adjustment. I was never that lucky when I ran FF nutes... I had to always carefully adjust my pH to the proper value.

Another thing that is likely to be happening is a salt buildup. FF also recommends several periodic flushes of the soil by running 3x the container size in fresh water thought there in one watering, to clear out the salts and any leftover nutes. If you haven't yet done a proper flush, this is also likely to be causing what is commonly known as a salt lockout.