Light Burn, Magnesium Deficiency, or Nute Burn?

[Adrienne]

I went back through the older threads to look for pictures that looked like mine and I just can't figure it out. Some googling popped up photos of plants with Ph fluctuations that looked similar. Any help would be greatly appreciated.

[Adrienne]

Well, I did the Fox Farms Sledgehammer flush - 2 tsp./gallon plus another gallon of distilled after the flush - because it was next on the schedule and I thought it might not be a bad idea to hit the restart button anyway given the size of containers I'm growing in. They looked very perky this morning. I will feed them the next watering.

[Schmokin]

Hey Adrienne. Answering your own questions here ;-)
My first thought when seeing your pictures was Light Burn. How close are the leaves to the light? And what type of light is it?
The marks could also be cause by nute burn. Flushing is a good first step to dealing with any nute issues, even deficiencies which can, ironically, be cause by overfeeding which can create a build up of salts around the roots which then blocks out further nutrient uptake.
Glad the flush seems to be working for you. Like you said it works as a reset. Good luck with the rest of it.

[Adrienne]

Hey Schmokin! I was hoping you might chime in. Thank you.

As for nutes, yes, I did the flush, they looked happy, but then within two days their color completely changed and I ran out and bought some Boomerang. That did the trick and I'm going to put them back on the feeding schedule the next watering.

As for the lights... So, I moved my plants outside a few weeks ago, but I have not been able to get them used to direct sunlight. They completely wilt. I had them under a full-spectrum CFL (1400 lumen) as seedlings, switched them to an 180w Apollo Hort UFO LED for a few weeks after, but then they just got too smelly and I put them outside on a NW facing balcony. They did receive direct sunlight earlier in veg, but filtered through a window. Right now they are in the shade. I'm not sure what the effect of not getting direct sunlight will do to them in the long run, but it doesn't appear that they can handle it. Funny because the plant that I threw on the balcony as a sink or swim can handle it no problem.

[Schmokin]

Hi Adrienne
Not sure what to add to this now. I have never heard of a cannabis plant that doesn't like sunlight.
Do you live somewhere outrageously hot?
Is there anything else outside that could be affecting them?

[Adrienne]

No, I live in the San Francisco bay area. Our weather is usually as perfect as a gardener could hope for only we are in a drought so the air is a bit drier than usual. I think the source of all of my problems is that I have them growing in containers that are too small (to contain size), and all of the mistakes a newbie would normally make are amplified by that. I would repot, but they've started flowering. And, whatever this strain is, it's a complete fuss bucket. Good learning experience though.

Thanks for trying to help.

[Schmokin]

I never even noticed the pots.....
It may be possible to repot now if you are careful and gentle with them. I have done it in early flower before and got away with it. I think you might benefit from it rather than leaving them in those tiny cups.
Try again indoors with your lights after the harvest and moving them in and out won't complicate things.
Next year, if you can, germinate your plants in spring time and then plant them outdoors directly in the ground. With your climate they should grow brilliantly. There some good info on this site about soil preparation etc. I cannot stress how much better most marijuana plants (all plants in fact) respond to being in the ground.
Let us know what you do and how it turns out.

[slo-han]

you can't throw your babies into the sun - period. They have to be introduced slowly - a lil at a time expanding the time till they get used to the sun. The sun is way more brilliant then the lights u have. They will sunburn like you would. You can't just "throw them in the ground either" soil prep is important. You can get mesh pots that are 4 feet across - and smaller and you put a prepared soil in these pots and we use drip water systems for these. That being said, you can put them in gallon sized pots but you will only get gallon sized plants. Bigger the pot - bigger the plant, if you are applying the neuts on a schedual. The plant will tell you if u overdose. That's when flushing comes in. This is not a hard hobby to learn if your getting good advice. Do a little more reading and don't depend on the advice your getting here. It's a lil on the lame side - -slo

[Adrienne]

Thanks to both of you for your responses.

I didn't actually throw them in the sun... They were in the shade for about a week to start before I moved them to the sun and they wilted. Moved them back into the shade, they bounced back, tried 3-4 more times to move them into the sun, and then gave up and left them in the shade. The plants I "threw outside" were some extra seedlings I planted just to see what they would do alongside my tomatoes and meyer lemon. Those did very well. Too bad they were males.

Size was always an issue for me and my intention was to keep them small, hence the cups. I do not have space for 4 foot pots, unfortunately. 4" x 7" balcony, no spigot. I used Ocean Forest and followed the trio soil schedule. Other stuff - Sledgehammer, Boomerang, and organic bone meal.

All this is neither here nor there though, because I had to go out of town for a week and unfortunately the watering schedule I left wasn't followed. I have one left that has been shocked back into the stone ages of veg which I will repot. I'll look into the mesh pots. Our Indian summers keep us warm through October, so there may be some hope left for that one.

ETA: My mother was/is an avid gardener, so I am well acquainted with growing things in the ground. Very new to container gardening.