please help, nute burn or deficiency?

[Topgear]

Hello everyone i need some help urgently, my plants are yellowing at the tips and it's spreading to the rest of my plants and i'm not really sure why, i don't think it's nute burn as i have been only using 3ml of nutrients per 10l of water. the soil/grow medium i'm using leads me to believe it's a deficiency ill put more info and pics below


What Strain is it? all autoflowers (7) heavyweight fast and vast(only five have this problem 2 are completely fine),(5) cream of the crop cash crop (all of them some worse than others) and (3) Delicious candy cheese(the worst affected and one has completely stopped growing just stalled and hasn't grown in 1 week)

Is it in Vegetative or Flowering Stage? flowering started about a week and half ago been in veg 3 and half 4 week, had this problem since week 2 slowly got worse.

Indoor or Outdoor? indoor.

If Soil... What is in your Mix? 15% vermiculite, 60% biobizz light mix(hydro shop ran out off all mix all i could get) and 25% coco coir.

If Soil... What Size Pot? 11.5L pots with good drainage holes

Size (Wattage) of Light? How Many? 2 x 450 watt mars hydro LED about 600 actual watts covering 1.2m^2

Temperature of Room/Cabinet? 23-30 degrees Celsius

RH of Room/Cabinet? unknown doesn't seem overly humid tho

PH of Medium or Reservoir? unknown ph meter i bought was broke upon delivery new better model will be here tuseday latest

Any Pests? no

How Often are you Watering? the fast and vast are twice the size of the other 8 and get watered every 2 days, the other two strains get watered every 3/4 days depending how dry the pot is at the bottom.

Type and Strength of Fertilizers used? biobizz grow and bloom. used bloom for the 1st 3 weeks until i saw preflowers then switched to bloom exactly 3ml used for every 10L of water for both solutions

Size or Square Footage of Room? 2.4x1.2x2m only using half of tent at moment tho so 1.2m^2

will upload pics below

 

[Topgear]

 

[Topgear]

i'll take more pics in a second phone is charging

 

[Stealthboat]

Might be lockout? 3ml per 10L isn't much, its not even a tsp per gallon. Maybe it lockout? Check your ph as soon as the pen comes. Most of my problems in growing have arisen from ph problems.

 

[Topgear]

Might be lockout? 3ml per 10L isn't much, its not even a tsp per gallon. Maybe it lockout? Check your ph as soon as the pen comes. Most of my problems in growing have arisen from ph problems.

thanks for the reply bro appreciate it , yeah it might be something to do with ph but i've never had that problem before the only thing different to any of my previous grows is the strain i heard autoflowers are very sensitive to nutrients hence the 3ml per 10l i normally use slightly more and the soil which is light mix plus the coco which is why i was thinking it could be a deficiency. they're all still growing tho except one which has stalled and the fast and vast are really stretching so hopefully it doesn't effect quality too much but i doubt i'll do autoflower again they seem to be a myth had much better results of 12/12 from seed than i think i'll get of these current strains.

 

[Stealthboat]

Yeah I hear auto's are more difficult/touchy. Hopefully you figure out if its deficiency, lockout or whatever is happening. Just keep us updated

 

[Topgear]

yeah ph meter will be here later today about 11AM hopefully, so i'll know if it's a ph problem soon enough. the only deficiency it looks like when comparing to a chart i found on here is zinc deficiency in the later stages so if ph is fine i'll order some zinc sulfate and see how that goes. the fast and vast seems to be a pretty good strain for an autoflower very bushy with plenty of bud sites but the other two strains are a waste space in my tent just want this crop over so i can switch back to photo period strains. thanks for your help.

 

[Topgear]

hi everyone PH meter arrived yesterday. the ph of my water is 6.9 i watered the plants and the run off water was 6.8 which from what i understand in soil that is perfectly fine and shouldn't cause lock out. so it might be zinc deficiency??? but i'm still not convinced it is that because looking at the pictures of zinc deficiency the coloring of the leaves don't look the same is mine and two plants are fine. but when i look at the deficiency chart it looks exactly the same. i may have over watered at the start but surely it would stop getting worse now i'm only watering every three days? and the bottom of pot soil is fully dry by the time i water. could it just be the autoflowers are hypersensitive to feed? and there is enough enough nutrients in light mix for the first 3/4 weeks? and they are burnt. i've never had this problem on any photoperiod strain i've previously done. let me know if you need more pictures any input would be greatly appreciated. thanks

 

[Stealthboat]

I went and checked BioBizz, I believe it is a soilless medium, so it can be run like hydro. The site even said "ph 6,2" on the side, i think that means aim for a ph of 6.2 with this stuff? For hydro, you want a ph of around 6.2-6, maybe this is the problem? If not that, I see your temps reach 30C sometimes? That is pretty hot, max of 28C would be better. Stirring up the top inch of soil 1 day after watering will allow more air to reach the roots so do that if you haven't been. Try this stuff and see what happens

 

[theengineer]

looks like calcium deficiency; are you using a cal/mag supplement? growing under LED seems to require it

 

[Topgear]

thanks for reply bro appreciate it . i have cal/mag supplement and use it probably once every week or two because the water in my area seems low in salts. this is the 1st grow i've done with LED's tbh i never even considered it could be that even tho now you mention it i do remember reading something about LED's needing more cal/mag for photosynthesis due to the full spectrum of light not being present? i'll start adding cal/mag into every water from now on see how it goes. i think the poor soil mix i chose plus it being autoflowers isn't helping at all because i have never had any problems with photo-period strains in my usual soil mix. i thought i was a pretty good grower until this happened it's opened my eyes to how much i have got to learn..

 

[Topgear]

I went and checked BioBizz, I believe it is a soilless medium, so it can be run like hydro. The site even said "ph 6,2" on the side, i think that means aim for a ph of 6.2 with this stuff? For hydro, you want a ph of around 6.2-6, maybe this is the problem? If not that, I see your temps reach 30C sometimes? That is pretty hot, max of 28C would be better. Stirring up the top inch of soil 1 day after watering will allow more air to reach the roots so do that if you haven't been. Try this stuff and see what happens

thanks for the reply and taking the time to look up the stuff i'm using . yes it has reached 30c but probably only a couple of times and not for extended periods of time it's normally sitting around 27c and drops to around 22c at night i don't personally think it's a heat issue. i normally try to avoid using ph down as i read it can kill of beneficial bacteria and with the ph being 6.8 i don't reckon it could cause the problems i am having now. but i will stir the topsoil to allow more air to the roots as more air definitely won't hurt and could help my plants in general.

 

[Stealthboat]

Ok, temps sound good then. Yeah idk the whole deal with ph down yet but I know using it is better than dealing with lockout 24/7. Good job stirring the top soil and adding some cal/mag