Troubled pitangatuba in grow room

[kybishop]

Hey all,

I set up a grow room this year to get through the winter months with some tropical fruit. My mango's are generally doing great, but my pitangatuba seems very unhappy:






The pitangatuba arrived about 2 months ago with green leaves all around, but now they're all mostly purple. The plant did put on about 2-3 inches of new growth (albeit with the purple leaves shown), so I'm not sure what to think... perhaps my grow light isn't putting out an adequate spectrum?

I'm using one of these: https://medicgrow.com/products/ez-8-led-grow-light

What are your thoughts? Anything I could do to help the pitangatuba along?

[tru]

purple leaves only means 1 of 2 things:
- autumn
- phosphorus deficiency

given that pitangatuba are evergreen, it is option 2 but other plants might be trickier to diagnose if they lose leaves naturally in late fall/early winter

if you do not fertilize your plants, it probably needs some fertilizer;
if you do fertilize, pH your soil and compare to this chart: https://www.researchgate.net/figure/The-effect-of-soil-pH-on-nutrient-availability_fig2_277669269

Phosphorus in general has a very small band of pH that allows high availability, and is why phosphorus deficiency is so common.
It's one of a plants 3 essential nutrients (N-P-K), yet one of the most sensitive with pH, which makes it hard to say whether you need to pH up or down without slurrying first

I think your growlight is waaay more than adequate, you can use photone if you have an iPhone and pay the $7 for the full spectrum led measurement (im a nerd so I do this and retest all the time as they grow but really, its not necessary unless you start seeing sunburns)

Also just a thought, distance makes light intensity decrease exponentially, so inches between plant and light really matter (as long as they are in acceptable bounds)

[Jaboticaba45]

Soil looks too dry. They will lose their leaves in winters if not happy. Will regrow in right conditions. Don't worry too much.

[kybishop]

Huh... just surprising it happened so soon after I got the plant. I did a pH test and I'm at 6.5 so it must just be deficiency. I up potted with a ton of bone meal, so crossing fingers it will bounce back. Also gave it a very good watering 😉

Thanks for the help!

[Daintree]

Bone meal might not be your best choice, since it takes months to break down. I'd go with a synthetic fertilizer that has phosphorus in it.  Some people may shoot me, but I like Miracle Grow.

Carolyn

[Ognin525]

My tuba does the same thing when i bring it indoors for the winter. I dont think its a problem with nutes, led lights lack uv light causing the purple pigmentation im thinkin. As soon as i take mine back outdoors it greens right back up! I feed it monthly and still every year it purples indoors.

[tru]

phosphorus is what plants use to make energy! Phosphorus is necessary to make 'ATP', the essential sugar that plants use to do just about anything. P deficiency is actually more common in younger plants as well, because phosphorus likes attaching itself to things it shouldn't and young plants don't have the developed root system to go searching for it. It happens really often in nature, and you've caught it quite early. It'll make a full recovery 

As far as fertilizer goes, I've tried it all, really; citrus nutrients on tropicals, weed nutrients on tropicals, foliar citrus spray (which worked pretty well to be fair), compost tea, bone meal, crushed sea shells, you name it... because I'd always been taught that slow-release fertilizer is bad for plants and doesn't work.

Let me tell you what... Science has come a long way. I caved and bought the full coverage osmocote, and it's the best decision I've ever made.

I do like half the dose that it says on the jar, and then just forget about everything other than water pH.
The plants have never looked healthier, and I've never tried so little for such great results.

If your setup is on the smaller side, it's $14 for probably 3-5 YEARS of full coverage nutrients.
You already mixed in the bonemeal so in due time it'll be healthy again, but a few months down the road treat yourself, I swear it's so worth it 

My tuba does the same thing when i bring it indoors for the winter. I dont think its a problem with nutes, led lights lack uv light causing the purple pigmentation im thinkin. As soon as i take mine back outdoors it greens right back up! I feed it monthly and still every year it purples indoors.

you got it backwards! UV light causes purpling effect : ) but the purpling and greening back up is interesting, do the light patterns change/perhaps sunburn even? most of the time it white-washes the leaves but sometimes I see purpling effect from sunburn on guavas for example

[Ognin525]

originally i had thought perhaps cold damage considering i regularly feed it but none of my other plants show cold stress. My tuba is the only plant that will do this. Even when plants touch my led lights i wont get burn. In my head i figured it was lack of usable light causing lack of clorophyll, for the past 3 years when i bring it back outside it greens up. I wonder if the wrong spectrum light could somehow create a deficency in a nute? I have a uv lamp from a reptile enclosure i think i might hook up today and see if more uv light makes more purple in it or greens it up. Once i found out itll green up during summer i kinda gave up and just kept my regular routine with it. Ill let u know how the uv lamp goes!

[NateTheGreat]

purple leaves only means 1 of 2 things:
- autumn
- phosphorus deficiency

given that pitangatuba are evergreen, it is option 2 but other plants might be trickier to diagnose if they lose leaves naturally in late fall/early winter

Pitatngatubas turn purple in the cold, doesn't matter if they're evergreen. It could also be to reject excess light, i.e. maybe your lights are too strong.

The plants look dried out and sunburnt. Some of that is normal this time of year, but that mix looks overly dry. They can't handle much fertilizer, might be overfed, meaning it can't take up enough water. Really doesn't look very bad though. I wouldn't add anything other than water.

[nattyfroootz]

What are your temps like at night?
I've got about 20 ir so planted and they purple up alm through fall and into spring

[tru]

Purpling of leaves comes from very cold weather, and is the plant's way of absorbing as much heat as possible from the sun (like wearing a black shirt on a sunny day).
Seeing as winter is but a myth in a growroom, I'm ruling out purpling from cold because I assume it's setup in a house, that probably doesn't go below 68F.

I have 3 pitangatuba (they are babies, idk if that matters) in my growroom that don't look purple whatsoever, and it got to be 6F last night

What I can say is OP, you see how your mango leaves are doing this? ~~~~~~~
This means that you're in too low of humidity

[kybishop]

What I can say is OP, you see how your mango leaves are doing this? ~~~~~~~
This means that you're in too low of humidity

Very good observation. I've been doing what I can to improve my growroom as far as humidity goes. Been slowly covering surrounding drywall in mylar, and thinking of doing the same with the ceiling. Humidity is a constant battle in there, even with a humidifier. You folks have definitely opened my eyes to me having been underwatering though, I'm much more used to my fig collection, which are basically cacti with leaves

As for temperature, I have it in my partially finished basement where it gets to high 40s at the absolute worst. I could see the low humidty being a contributing factor for the tuba. Going to close off some more holes in there now to try and get the humidity up during this crazy cold spell.

[NateTheGreat]

Purpling of leaves comes from very cold weather, and is the plant's way of absorbing as much heat as possible from the sun (like wearing a black shirt on a sunny day).

That's not true, and it's not true that leaves only color for phosphorous deficiency or deciduous plants in the fall. Anthocyanins protect the plant tissue against freezing.

"There have been a surprisingly large number of hypotheses about the potential ecological benefits of producing new anthocyanin pigments in senescing leaves. From a physiological perspective, the most common explanation is grounded in the idea of protection against external stressors such as cold, drought, ozone, UV radiation, or pest and pathogen exposure. Anthocyanins are generated following exposure of the plant to a range of stressors, and anthocyanins have various biochemical properties (e.g., as a chemical antifreeze agent and a powerful antioxidant) that may help leaves better survive stressors. "

http://blog.cdnsciencepub.com/what-experimental-branch-cooling-tells-us-about-the-beautiful-reds-of-fall/