Milky Way F1 light burn ?

[AlanJohnson]

Hello, here's my MW F1, not being cocky I know she's doing well 18 days into flower. But once it leaves the canopy the leafs are getting a little yellow, it's had a little CalMag on the last feed and a little tad of extra N, all new growth below that is perfect so I'm thinking light burn as they still look like decent fan leafs, my panel is at its highest, only 100w and doesn't get to hot as long as there is air from a fan (even on low speed) the max it gets directly under is around 28/29⁰C, the tip of the Cola is 2.5" away from it.

What do people think, just light burn ?

Thanks

Those pics don't do it justice, under the light you can see the yellowing coming in a little from the outside of the leaf, anything lower than 6" away comes out perfectly albeit a tiny bit of nail polish lol

 

[Phyto]

Sure looks like it, either raise the lights or turn them down.

 

[AlanJohnson]

Sure looks like it, either raise the lights or turn them down.

That is the problem, my DIY setup made from an old set of draws has limited height and the light panel is as high as it will go and I cheaped out on £20 and didn't get a brightness control ballast, heat isn't the problem as directly under it I had it at 26⁰C with my fan on low rotating over the canopy.

She had a feed before of 2ml/L Canna Bloom and I put 1ml of Canna boost in an got it to PH 6.0/6.5 (I had to use my litmus paper.....which I prefer TBH) due to my not cheap PH and EC all in one not working properly, it needs recalibrated.

I reckon I'm just going to let it ride as it doesn't look unhealthy and most leafs are praying and it's been under it for 19 hours as I nodded off, normally I will give it 14 hours.

I have put in my spray bottle 1ml of Veg, and a few drops of baby bio (a general mainly very concentrated Nitrogen fert, and I'm just spraying the legs, trying to keep any away from the buds.

I'm hoping it will give it an N uptake.

Thanks mate

it looks really yellow under the lights.

 

[KG1]

If you put a thermometer under a light it will track light radiation not air temperature.

Thermometer need to be shaded from all light and wind to read true.

The science of how to read air temperature is better explained as if I went to the desert, weather report accurately says air temp is 45c. But I put a thermometer unshaded in the sun and it now reads 90c as the sun heated it past air temps.

Unfortunately with bad readings some then try and blast too much wind and it creates a bad environment.

Seems counterintuitive as most seem to put theirs in the light but if we break light and heat transfer down into radiation conduction and convection we see we want to omit all light radiation conduction just leaving us the air which we read by convection as the air passes slowly over our meter noting that wind will have the opposite effect and cool it.

The met office actually uses this science to bring you your local air temps and so should you to get an accurate reading of which for most of us it's pretty similar to the air in the room we grow in.

With extraction I can't heat a tent by much so feel just monitoring the room temp and not the tent tent works perfectly plus gives me accurate readings without placing a thermometer anywhere near a light.

Technically 150w is a crap heater of air, not only is it inefficient but if so low wattage I'm sure you can see the difference between that and a small 500w foot heater. Of course it feels warm under it but that's you precieving light radiation not air temperature.

Hope that helps, training and topping could keep the plants lower but I'm sure you really want to pull the trigger on a mars hydro 90x90x1.60 tent and pimp this grow up a level

 

[AlanJohnson]

If you put a thermometer under a light it will track light radiation not air temperature.

Thermometer need to be shaded from all light and wind to read true.

The science of how to read air temperature is better explained as if I went to the desert, weather report accurately says air temp is 45c. But I put a thermometer unshaded in the sun and it now reads 90c as the sun heated it past air temps.

Unfortunately with bad readings some then try and blast too much wind and it creates a bad environment.

Seems counterintuitive as most seem to put theirs in the light but if we break light and heat transfer down into radiation conduction and convection we see we want to omit all light radiation conduction just leaving us the air which we read by convection as the air passes slowly over our meter noting that wind will have the opposite effect and cool it.

The met office actually uses this science to bring you your local air temps and so should you to get an accurate reading of which for most of us it's pretty similar to the air in the room we grow in.

With extraction I can't heat a tent by much so feel just monitoring the room temp and not the tent tent works perfectly plus gives me accurate readings without placing a thermometer anywhere near a light.

Technically 150w is a crap heater of air, not only is it inefficient but if so low wattage I'm sure you can see the difference between that and a small 500w foot heater. Of course it feels warm under it but that's you precieving light radiation not air temperature.

Hope that helps, training and topping could keep the plants lower but I'm sure you really want to pull the trigger on a mars hydro 90x90x1.60 tent and pimp this grow up a level

It's basically air temp in the grow box whatever you call it, if the central heating is at 23⁰C then the grow is 23⁰C maybe 24⁰C as TBH I don't even check anymore and there's air always moving over it.

These days I just go off what my girls are looking like, if they are not praying and dropping then I will put them in my dark wardrobe until the next day, this usually happens only in veg though when there's lots of plant matter.

That's when was still stretching last week, it's only now now those top leafs seemed to be getting bleached, any fan and those little ones you get that I don't know the name of are fine, do I'm expecting them to start going really yellow near harvest when the bud starts eating them, she got feed 2 days ago with no more colour change just the buds packing on weight now.

I'm not a science guy when it comes to growing now due to the pain in the arse it was using the Wilma's in 60/40, yeah you 6ft plant and rugby ball Colas but it was so unforgiving, especially each 8 pot Wilma has its own tank and we would use 4 of them with a 600w HPS over each of the 4 Wilma setups.

The lower one has just been awake since 08:00 and it 09:30 now and the pics are a week apart.

I'm just going to leave her now apart from her Canna Terra Bloom (down to 2ml/l as at 3ml/L that's when she started to paint her nails) oh and I also stick in a few drops off baby bio and PH it to 6/6.5 with limus paper but the more accurate 5.5 to 9 stuff, that's about the only test I use these days.

I read about people using boost products ect and when I've looked, no one company can decide on when to use PK, or how many times it tells you to use CalMag and the rest.......are these mainly gimmicks? Just I've got sample bottles of things like (huge bud stimulator) (Big and Hard lol bud stimulator ect lol.

Do any of you people use them and are they worth it, I do have CalMag and will use it with a few drops of N if they look off during Vedge, but never any boost or the like.

Info on that on that would be appreciated also.

Thanks,

Srece6