Help heat stress?

[Breezy]

I noticed the two closest colas to the light look like their stretching wierd I'm not sure if this is normal or not as it's my first grow.

Temps are 76light on 70light off
Humidity 27%
pH 6.3
Nutes biothrive bloom
Lights 250hps and 150 HPS - distance from both is 9 inches
comin to the end of 5th week of flowering

Is this normal ? Or is their a problem ?

Thanks again

[NebulaHaze]

They look great to me! I can see what you mean that the tops of the buds are stretching but I think the buds may just be developing and getting bigger/longer, which is a great thing. As long as the buds are staying symmetrical all the way up (like they are), and you don't see any long, thin spires (which are a sign of heat/light stress) I think you're good The buds look very well developed for week 5, and definitely look like they're going to fatten up even more over the next few weeks!

[desertdan]

Why do indoor plants get heat stress and outdoor do not? I have seen outdoor with no stress at105 degrees as long as they have water. From what I read here plants indoors can take no more than 80 degrees. Why?

[NebulaHaze]

There's two big types of stress that often get lumped together, light stress and heat stress.

Outdoors, plants don't really get light stress because the sun is the same distance away all the time. Cannabis plants are adapted to deal with the light levels produced by the sun on a clear day, and thrive under lots of light. However, if you have really powerful lights when growing indoors, and keep them really close, they'll actually be delivering more light to your plants than the sun ever could. When that happens your plant leaves can't "work" hard enough to process all that light. As time goes on the leaves starts shriveling and looking burnt/deficient from overwork. That's light stress, even though it often looks similar to the symptoms from heat stress.

When it comes to heat, it depends a lot on the strain and the setup. Some strains are great at dealing with heat, for example Sativa and Haze strains tend to be very heat-resistant. Other strains, like Indica-based strains, often start struggling at much lower temperatures.

However, many indoor growers have their plants in 95°F or even higher and their plants survive. But just like outdoors, plants grow better at 80-85°F than at higher temperatures. Even outdoors, a plant won't grow as good as it could if it's getting 105°F weather every day.

If you have a plant that's suffering from light stress, it will be a lot more sensitive to heat stress and vice versa. This makes it easier to stress your plants indoors because if the grow lights are too close it can seem like plants are incredibly sensitive to heat when partly it has to do with the amount of light, too.

[Breezy]

That's awesome thanks this website is the best by a long shot .

One more question the plant is really yellowing I realized I was giving it half the bloom nutes I should have ,I can see some signs of brown curling at the tips . Is this all part of the natural process of the plant ?

[NebulaHaze]

It's normal to see some yellowing, but you do want to make sure the plant has enough green leaves to last until harvest. Can you post a picture of the whole plant in the setup under natural light? A closeup of one of the affected leaves (while still on the plant) is also really helpful If you see a little brown curling at the tips it's probably nutrient burn which is no big deal as long as it's not spreading.

[Breezy]

Here are some pics. If it is nutrient burn how do I go about fixing it and also the relative humidity is at 22% should I raise that also ?

[NebulaHaze]

You can't actually get rid of nutrient burn, once it's there it's there, but it's mostly just cosmetic. Your plant does look pretty pale all over. I would guess either it needs more nutrients, or the light needs to a little bit further away (HPS are really powerful, and if you keep them too close your plants can get light burn even if it's not too hot).

[Breezy]

Well a beginner mistake I was making I is feeding it half the dose that was recommended I started today with full nutes for a week then possible flush ? Also the lights are 9" away from the highest cola. Thanks again for the help nebula

[Breezy]

Bump please

[NebulaHaze]

9" away is pretty close for an HPS, I would move it a few inches further away to see if the yellowing stops