heat stress or nute problem?

[Rusty Trichome]

Water ph a tad high, but likely the soil buffers are still doing their job. 6.3 to 6.8 ph is acceptable range for ingoing liquid ph. (for both, the water and the nutrient solution) Did you get a soil probe or a ph pen?

Miracle grow instructions are usually for a two week period. Go with the low figures recommended, and sneak-up on the maximum dose the plants can handle. I believe I was using a teaspoon per gallon per week. (1/2 teaspoon per gallon, twice a week) Been a while though, so you'll have to double-check if that sounds right per instructions. (too many nutrients used, too crappy a memory)

Did you let the leaves get too close to the light?
Check the undersides of the damaged leaves carefully, and look for little black spots. If you see none with a magnifying glass, then it might be either some drops of water or nutrient solution splashed on the leaves and left to dry, (a no-no) or possibly overdoing the MG. Way back when I used MG, I had better success dividing the feeding days into twice a week at half-dose. And actually...I've never lost that habit regardless of the nutrients I use. (it works well)

[evilbeaver]

I ordered a soil tester, not arrived yet. Tryin to get my hands on some litmus paper as well seems nowhere around here sells it anymore though.

Think it may be possible I overfed them, and in fact started feeding way too early. You're right about the MG feed routine, the pack recommends 1.25ml spoon in a litre of water every 2-4 weeks.

Don't think I let the plants get too close, I've been over-cautious in fact. My flatmate has his almost touching the light, where as mine are a few inches. His look fine (and are bigger). I don't really want to do this as I work 24hr shifts and the rate its sprouting recently would worry me. Although my flatmate keeps an eye on them :thumbsup:

Can't see any black marks on the bottom of the leaves. Will try posting an updated pic later. cheers man

[evilbeaver]

I've lost the cable that connects my phone to my pc so can't upload any photos atm, but the plants are looking really good.

I've not given them any nutes since my original post here, and have also been watering exclusively with bottled mineral water. The evil spots haven't spread any further and theres lots of fresh growth going on. I will resume feeding soon and see how they react.

If everything goes to plan I think I'll put them into flower in around 3 weeks time and hopefully will have some nice results to show you guys, thanks a lot for your help :thumbsup:

[Rusty Trichome]

Good luck, and keep us informed... :thumbsup: