Brown edges and one yellow leaf

Hi there, I've done some research on the 'Guide to Nutrient Deficiencies' and come up pretty stumped as to what problem we have.

It looks like it could be cal/mag deficiency and some burn marks from the light, but I'm unsure so ANY help will be appreciated...

Grown in pure coco (Should perlite be added?)

Using Formulex @ 7.5 ml per litre with every water (usually once a day with 10% run off in 3L plant pot) - Should I switch to another set of nutes? (Suggestions would be great!)

Grown 3 inches away from a 125watt blue CFL @ 6400k

As a first time grower I apologise if I am abusing this forum!

Cheers

Nute burnt because you fed the little plant too much every day. Flush with 5.8 water and dont feed every day its too small and is now sick so stop feeds and reduce waterings for a week or until clear recovery. When you resume feeding cut nutes by 20% .

Thanks very much, BUDS, will try that tonight and this week!

It's hard to know with coco as a lot of people say it's the same as hydro, so I thought it needed the same amount of nutes as hydro; supplying the plants with a little less than the recommended dose on the bottle... I guess that's the wrong thing to do until the plant is a lot bigger??

OK, I flushed the plants with distilled water yesterday. They have got visibly worse today but I suspect that's because of a delayed effect of over feeding... is that right?

I was wondering if I should flush again... The coco's pH is now reading at 7.2. Should I flush with a stronger 5.5 solution today?

I am also now getting crispy dark green parts on new growth and the top leaves, is this still a symptom of nute burn? (can post pics)

Any help will be greatly appreciated...

Best

thay look the same as my 3 girls at the moment only im 5 weeks into flower and it is over feeding
thay may get worse before thay show signs of improvement an that could take a week or 2 but buds is right cut down watering and stop all nutrients for several days

GestureStew said:

OK, I flushed the plants with distilled water yesterday. They have got visibly worse today but I suspect that's because of a delayed effect of over feeding... is that right?

I was wondering if I should flush again... The coco's pH is now reading at 7.2. Should I flush with a stronger 5.5 solution today?

I am also now getting crispy dark green parts on new growth and the top leaves, is this still a symptom of nute burn? (can post pics)

Any help will be greatly appreciated...

Best

Click to expand...

*BUDS nailed it. The crispy is continuing nute burn.

I would only water for a spell, then come back with half-strength nutrient once they've recovered and are showing healthy new growth. cn

OK, they're still alive and doing a lot better thanks to all your help. Big thanks to you! I now have another problem, the leaves seem to be getting paler, losing their sheen​, and cupping up slightly...

They're back on nutes at half strength and are kept around 26-28C in light and 20-22 at night @ 20/4. Fan is continually oscillating gently on the plants with good ventilation. The water/feed I give them is always 20C with a ph of 5.7-6.

A couple of the brown burns in these pictures are from touching the light and the others are from the previous nute burn problem so they might be worth ignoring... sorry the pictures aren't great they were taken in a rush.

A lot of the stems have turned purple but these girls don't get temperature shocks at all...

Does it look like a mag def.?

I'm think of doing another big 5.5pH flush tonight to refresh them.

Best