Please help diagnose - New grower

My plants are 4 weeks old. Planted indoors with grow tent and CFLs in soil. Temp between 18 and 32 degrees Celsius. Planted in potting mix and they all did really well for three weeks. I noticed the bottom leaves started turning yellow so I thought nutrient deficiency and gave them a feed, it didn’t help. So then I gave them a spray on the leaves with Magnesium 2 days ago and can’t notice a difference yet.
The top leaves have now clawed slightly , probably because I overfed them trying to fix them, so I gave them a big water yesterday which was drained.
What should I do next? Leave them a while or treat somehow?
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What brand of potting mix? Most are not good for cannabis plants.
Most people on here recommend FFHF or FFOF if using soil.

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Looks like nute burn with some mag deficiency . What’s you ph and ppm from your run off? A support ticket will help with all the info

Strain; Type, Bag seed, or NA

Soil in pots, Hydroponic, or Coco?
System type?

PH of runoff or solution in reservoir?

What is strength of nutrient mix? EC, or TDS

Indoor or Outdoor
Light system, size?

Temps; Day, Night

Humidity; Day, Night

Ventilation system; Yes, No, Size

AC, Humidifier, De-humidifier,

Co2; Yes, No

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Agree with @Watt-Sun and @Jstar. Most potting mixes have timed released nutes which drop ph a lot for regular flowers.
Also looks like some deficiencies calcium / magnesium. CalMag and Epsom’s for that if it turns out this is the case.
Fill out the help ticket and Id the potting mix for Jstar and we can work it out.

That’s a big swing in temps.
I’d also recommend moving her to a bigger pot. She will get root bound if she’s kept in that. Can’t go wrong with fabric pots

Sorry couldn’t work out how to do a support ticket, but I’ve answered the questions below:

Strain: G13 (although not sure if I believe my mate that gave them to me)

Soil: potting mix from hardware store here in Australia. It’s called: Osmocote Premium

PH: I haven’t tested the run off. I tested the soil at 6. I will buy a proper test kit tomorrow.

Nutrient mix: I added a photo

Indoor in text 80cm x 45cm x 80cm (small tent)

Lights: 4 x 25w CFLs and 1 x 130w CFL. All at 6500k

Temp: 18 at night and 32 max at day (Celsius). I also have a heat matt under the pots to keep the pots warm 24/7

Humidity: 60%

Ventilation system: no

I hope all of that helps, and thanks so much for your advice!

I did spray the foliage with a mag spray, pic attached. How long will that take to help?

CO2: no

A.C, humidifier: no

image image

Yeah true , I live in a cold climate, so I have lights off during the afternoon when it’s the warmest. The day time temp has dropped to about 28 now it’s colder.

My grow tent is only 80cm x 40cm x 80cm. So I can only have small plants. The pots are 5 litres. What size pots should I have them in?

Thanks so much for your help

I’m in Australia and it’s called Osmocote Premium. It’s a mix that has food in it already. I’m guessing that was a bad move now haha

Thanks heaps. I sprayed it with just magnesium. How long will it take for that to help?
I’ll go buy some mag/cal and use that instead.

Using a fabric pot would be better . . . but that’s not the problem. Unless it is. You seem to have a mobile nutrient deficiency (mobiles affect lower and older leaves first). I’m wondering if you were overwatering (which is very easy and common). Considering the pot it is in, it may not be getting enough drainage causing root rot. On the other hand, the leaves don’t appear overwatered to me. If it’s a nute deficiency, it looks like Nitrogen to me.

Get the biggest fabric pots you can fit in your space. The nice thing about fabric pots is the plant won’t get root bound even when they get big, although you will be watering quite often when you have a large plant in a small pot.

Once you get your runoff ph and ppm that will give you a much clearer picture of what you have going on.

If you can pick up a ph meter and make sure you are on target there, then the calmag / Epsom salt (or magnesium) will start bringing her around. I don’t spray myself so I don’t know how intake works compared to being in H2O. The important thing is to get consistent nutrients etc.
It takes a bit of time to learn and even problems help you build up your knowledge base. Don’t get frustrated and keep on growing! :grinning:
There are other folks from Australia here, but at the moment the names escape me.

Thank you!

The mag spray I gave them seems to be working already!

I did test the soil which was at 6.

I have also discovered I was under watering them.

They have grown so much in the past two days and leaves are looking healthy whoo!

I will invest in some mag/cal though :slight_smile:

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I’m sure that is a big relief! Glad everything is starting to come around.