Heat stress or deficiency?

Hi, I am about 1 month into flower on a SE Asia outdoor Sativa grow in a greenhouse, and have discovered over the last few days that a small number of the leaves on the lower plant seem to be suffering from....?

In the last couple weeks I have suffered extreme heat and humidity as the rainy season has extended longer than usual (40 degrees C and 90%rh at times). Thankfullyonly about 5% of the leaves are suffering at this point, though I am concerned it may progress.

Any help appreciated, ty

Would be nice to see the rest of the plant.

Yeah, hard to make a call, but weeks 4-6 are when most plants start getting nitrogen deficient, and 2 of those leaves are yellow and lime green. The plant could easily be deficient in other elements too.
It looks deficient to me but I’m in Canada and don’t get to see any heat stressed outside plants.

Here is the rest of the plant, if this helps. As you can see, it looks pretty healthy although due to humidity levels the flowering process has somewhat halted over last couple weeks. Or, perhaps that is partly due to a deficiency? Please help!

They don’t look so bad. Not the darkest green, but they’re not real deficient looking.
Are you feeding them? They will need feed to make bud mass. One of the ways they tell you to slow down plant growth in gardening books is to deny the plant Nitrogen.

Tropical Grower said:

40 degrees C and 90%rh at times

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Great looking. Hemp can tolerate extraordinary heat stress but not permanently.
At least this is even too hot for warmth loving fungus. In a later stage, that could have ruined the bud.
You must get that both down.

Tropical Grower said:

SE Asia outdoor

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I love people with balls of steel!

Tropical Grower said:

Here is the rest of the plant, if this helps. As you can see, it looks pretty healthy although due to humidity levels the flowering process has somewhat halted over last couple weeks. Or, perhaps that is partly due to a deficiency? Please help!


View attachment 5000991View attachment 5000992

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That looks like a pure sativa flowers (less organization). The lower leaves you lost are likely from lack of light penetration. Nutritionally they look good. You have months left, enjoy it.

Thanks for the responses guys! Somewhat reassuring me that everything should be ok.

As far as feeding is concerned, I am giving them compost tea (molasses, fish fertiliser and worm castings) every 2 weeks, though I include a little epsom salt in this every month or so. I also liven the mix up with some fresh worm casting, dolomite lime and bone meal every month or so. I also included a little gypsum a couple weeks ago however will not include that again as I believe that's a 3 monthly thing, and hoping for harvest around that time.

Usually 2 or 3 pure water watering's in between any other feeding, typically every 2nd or 3rd day dependent on the weather (every 3rd day currently due to the weather/high humidity).

Any pointers regarding this approach to feeding (whether to increase this at month 1 flower in particular) would be great!

Thanks again for all responses.

Hello Guys, how're you doing?

Just posting here in a hope for some help, instead of open another thread like this.. These 2 photos are almost 4 weeks a part.

Could you help me about this plant? What it looks like to you guys? Could it be heat stress? it's been couple weeks of high temps, like 30ºC all day in the growroom. They're 7 week flowering..

Coul it be nutrient burn?

By the leaves, you guys can tell what could be the issue? The buds are underdeveloped, not growing or fattening at all.. and I have two other plants that are at slow peace too, but not like this one. It's leaves are just yellowing and drying, buds not fattening.. 150w common home led lights... soil it's a mix of peat, vermiculite, soil, worm casting and frass. With a little bit of lime.

Thx guys