inexperience grower needs help guys!

hi guys. my third grow but first with autoflowers. and so just in time the problems have arrived.... anyway. my project is.

6 different strains all autos (Snowstorm, Auto Mazaar, Bubblelicious,Speed Devil,Fast Bud,Diesel Ryder). 3 of them in 14 ltr/3,9 gal pots and 3 in 18 ltr/4,7 gal
tent dark room 90x90x180, light HPS 400 dual spec Philips son-t-agro,exhaust fan RVK 125mm (325 m3). i have 20/4 hours light schedule.

soil Biobizz allmix, Nutes Biobizz (grow,bloom,ruite juice). my temps are 20-27 and humidity is always beetween 45-60%.my water ph is 6,4-6,7 always. and my runoff when i water is 6,4-6,5.i use tap water but i leave it 2 days in a tank for the chlorine. the first 15 days the were under 210 watt CFL 6500K. now they are under HPS.

till day 16 they looked fine. first at day 17 the Mazaar started to appear yellow/golden spots on the middle leaves. now the same spots are at 4 of them. also the speed devil has a hole on one of her leaves.it seems like it's been bitten somehow i think. i haven't added anything yet.just water. i was thinking of starting next week a very low dosage of grow food... also today i discovered a spider net in beetween 2 leaves.i checked with the microscope but i didn't find anything on the leaves.... if i have something like spidermites where exactly should i have to look on the plant? sorry about the pics.they were the best i could get.

here is the problem



and here are today at day 20.


any advice would be very helpful...

your soil looks like it has very little perlite. when you water does it drain fast? or does it sit there like a puddle. and it also looks very wet.

no. it has 30% perlite in it. it's biobizz allmix. i just took the pic just after i waterred them...

Spidermites are smaller than a pinhead. Look on the bottom of leaves for specks if you think you may have em.

I think your plants look like they are doing very well. My plants always experience a bit of yellowing in the first couple of weeks. I would be more concerned if they were bigger and yellowing on more leaves.

is it possible these yellow/golden spots and the little cuts on the leaves caused by nitrogen def? someone told me that but i thought N def starts with yellowing the lower leaves(whole discoloration not spots). i'm going to add some cal/mag vitamins today in the water and i'm thinking of foliar feed them.or is it better to water them wih the cal/mag? they have about 300mg of calcium each pill.are 2-3 pills in 10 litres water enough?

Bro its a major shock for a seedling goin from a cool 20 deg fluro to super high intensity 600w at 27deg. They are stressed but should be ok in 1-2 weeks, no feeding and little to no watering in this stressed period.

i guess you are right.. i didn't think this although in my previous grow when i changed from 200 to 400 watt (cfl lights) they seemed a bit of "depressed" for a few days. but they were just droopy.not spots.

anyone knows about this?

i'm going to add some cal/mag vitamins today in the water and i'm thinking of foliar feed them.or is it better to water them wih the cal/mag? they have about 300mg of calcium each pill.are 2-3 pills in 10 litres water enough?

Click to expand...

hi guys.. it's me back. i think i tried to take better pics so take a look again to help here!! the problem seems to affect all my plants and is getting worst i think. the New leaves are starting to yellowing... specifically there is a discoloration beetween the veins...i think you will see it in the pics.. the spots looks like they stopped i guess... or they didn't get much worse.... anyway.. the ph of my soil is 6,4-6,5. temps and humidity are good. i haven't feed anything yet cause allmix is hot soil... the only thing i gave them was calcium vitamins in their water one time, cause i couldn't find cal/mag supplement these days.. today i'm planning of giving them their first food. 1/4 of biogrow and cal/mag.

what do you think?

Try Mg. Epsom salt ..tsp to a gallon of water for a start.