Help... soil

Hi, I am into day 57 (week growing 3 auto's in SOIL- green gealto, royal ak and cookie. It's my first time, so please forgive any ignorance and thanks in advance for any help. Everything ok-ish up to now, apart from a slow and shaky start, thinking I underwatered first few weeks and she was only 35cm tall on day 32, she's now 77cm. Gelato has suddenly started to display some deficiency, I tihnk, in the leaves. Bear in mind there are only two leaves showing this but they are both fan leaves coming from the main cola up top.

I've been slowly upping the nutes and my latest feeding schedule was: Alg Mic 2.5ml, Bio Heaven 2ml, Cal mag 1ml, Grow 1ml, Top Max 3ml, Bloom 3ml. I've noticed my run off ph gradually reducing. The latest for this plant was - in at 6.47 - out at 6.01.

I'm not sure what to do. It looks like it could be a magnesium or nitrogen or sulfur deficiency, or perhaps there's too much salt in the soil causing a lock out? I've now got a meter to measure PPM's in additon to Ph but only just got this so haven't been monitoring up to now.

Plan of action was to flush through 10 litres of really weak nutes, then give a normal watering with nutes above. Lift the light to give her a break. Would be very grateful for any advice.

Thank you

What medium?

Never seen before.

I'd prolly get some bottled water and submerge the pot for 30 minutes to soak.

Gentlemencorpse said:

What medium?

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Sorry I shoul;d have said - SOIL

recharge said:

Sorry I shoul;d have said - SOIL

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I meant specifically... people call all kinds of things soil these days that are actually peat moss or the likes. But if its actual potting soil my guess is pH issue. If your nute solution is going in at 6.5 and the runoff is 6.0, the root zone pH is closer to 5.5, which is pretty low.

I'd flush with plain water pHed to 6.5 until the runoff comes out to something close to the same, then resume feeding every other watering.

This is the leaf on one of my plants where the root zone pH was too acidic ... looks like a similar issue to me. I thought it was a chlorine issue until another user on the site got me on the right path.

Gentlemencorpse said:

I meant specifically... people call all kinds of things soil these days that are actually peat moss or the likes. But if its actual potting soil my guess is pH issue. If your nute solution is going in at 6.5 and the runoff is 6.0, the root zone pH is closer to 5.5, which is pretty low.

I'd flush with plain water pHed to 6.5 until the runoff comes out to something close to the same, then resume feeding every other watering.

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Sorry for late reply, I'm using BioBizz All mix. I read somewhere else that I shouldn't be upping and downing the ph with this type of soil as it acts as a natural buffer and will "right" the ph by itself. Have you had experience growing in this paricular soil? I'm using all BioBizz nutrients as well.

Thanks

Gentlemencorpse said:

I meant specifically... people call all kinds of things soil these days that are actually peat moss or the likes. But if its actual potting soil my guess is pH issue. If your nute solution is going in at 6.5 and the runoff is 6.0, the root zone pH is closer to 5.5, which is pretty low.

I'd flush with plain water pHed to 6.5 until the runoff comes out to something close to the same, then resume feeding every other watering.

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btw - I did what you suggested. Each plants took around 11-12 litres and I finished by giving them a weak dose of nutes. No one has died thus far and it's 24 hours on so fingers crossed!

I can confirm what Gentlemancorpse is correct. Best course of action is flush without nutes. Build up of salts can cause roots to actually have problems up taking nutrients and can lead to nutrient lockout. Nutrient lockout can look like various conditions, ie pH issue, nutrient deficiencies, light burn.
Flushing with pH'd water no nutes is the solution.