Problem with sudden death

[2Whitty]

Hi all, Newbie here. I need some help please.

I have pics here of my sad 8 week old dwarf! It finally died due to something I do not know and need help to figure out if it is a soil borne disease before I plant again.

Outdoor grow in soil mix of 40% fresh organic soil mix (Packaged) (No nutes), with 30%Coco fibre, 20%peat moss & 10%vermiculite.
Planted in early spring, gets about 6 hrs direct sunlight & 6 hrs ambient light/ shade each day. Days getting longer now up to 14hrs daylight here is SE Qld. Australia

8 weeks old only got to 300mm (12") tall but was starting to flower. I topped it twice, going well, fed Charlie Carp (NPK 10,2,6) every 4 -5 days and in the last 2 feeds added a dash of liquid Potash. had also added Seasol, a soil conditioner (No NPK) about 7 days before. I also added lime and baking soda to raise the ph twice a few weeks apart with the last application about 7 days before it died. Ph was 4.5 is now about 6.5

It did rain for a few days the week before then it just wilted & died in 24hrs. I had a smaller seedling too, 6", it also just wilted and died in 24hrs a few days before the 12" one. I have a third one thats looks like it's going to go the same way to now. Pic attached of that too. The others did NOT look sick before they wilted and died. May have had aphids as some other plants nearby did and i did wipe a few off the leaves. I'm not sure if the small spots on the stem are aphids or not.

Strain - Unknown seeds came from grower in Vic. Australia
# of Plants - was 3 now .5
Grow Type - Soil
Grow Stage - Vegetative
Bucket Size - garden bed
Lights - (2) 400 Watt HPS
Nutrients - see above
Medium - see above
PPM - ?
PH - 6.5
RH ?
Room Temperature -ambient temps 17C - 26 or 28C (63F-79/82F)
Soil Temperature 25C (77F)
Room Square Footage - 3' x 3'
Pests - May have aphids. a few spotted on leaves

Thanks for any help.

https://www.420magazine.com/community/gallery/1449283​

https://www.420magazine.com/community/gallery/1449284​

https://www.420magazine.com/community/gallery/1449285​

https://www.420magazine.com/community/gallery/1449302​

https://www.420magazine.com/community/gallery/1449303​

 

[smeghead]

2 Whitty, thats a damn shame my friend.
It looks like they rotted away, although the first one looks as though its been eaten at the base?..
I know in aussie you have some nasty big bugs, any burrowing grubs?
If nothing ate it?, then I say a little to moist. Your soil mix looks alright except id replace vermiculite with perlite.
Vermiculite holds alot of water, perlite doesn't. That will help with drainage.
Let the plants dry out between watering..cannabis really likes dry toes between feeds.
If its gonna rain, then let the rain do its job and stop watering yourself, just top up with a bit of food when it dries out again.
Last thing PH isnt as important outside, but 4.5 is way to low..6.5 that you had is a bit more like it.
Hope you get it sorted bud, if im not wrong, you down there are just into spring...your gonna grow some monsters!!
Happy growing.

 

[smeghead]

Whitty, me again.
Just looked at your soil again, deffo replace vermiculite with perlite. Raise the amount of perlite to 25% and lower the cocco and peat a little, both cocco and peat can hold water..maybe soil 50%, perlite 25% for drainage then maybe the other 25% a mix of peat and cocco.

In the growers forum, there's an organic growing section in which there is a thread called building a better soil.
Lots of info there about soils..lots of great growers on here willing to share and help..get round and have a read, but don't be shy about asking questions. .

Lots of aussie growers joining at the moment. .can I suggest looking for journals in progress or use the search bar at the top.a few members to look for.

Aussiebluethc
Hortishorti
Both aussie members

Also for outside growing, 420 members
Colamonster
Sphnx
Good luck bud, we'll get it sorted.