rust spots on seedling

[presto]

it started off as some yellowing in the middle of the leaf and then started to go rusty. 3 out of 10 are showing these types of symptoms.

i thought it was burn at first but there's no yellowing/rusting at the leaf tips at all. it's all contained on the middle part of the leaf.

they're about 10 days old planted in soil. they were started in rockwool and as soon as the root showed on the bottom of the rockwool, i planted the cube into the soil.

the only feeding i did was foliar feed them with some EJ Microblast one time. could this have caused the yellowing/rusting on the middle of the leaf?

i have a camera and could take pics but i've never been able to upload pics on this site.

 

[BigJilm]

Need more info
is the soil preferted? Ammended with perlite or aerator?
Do you check pH?
Have you watered?
What was the concentration of microblast that you foliar feed them?
Are the leaves wavy and twisty? Drooping?
Temps and humidity?

 

[Guest]

the yellowing and rusting would come in from the tips if the plant ate from its roots.. but you foliar fed.. so it makes perfect sense to me. sounds like nute burn.

dont feed seedlings so early.

 

[presto]

Need more info
is the soil preferted? yes; 3 month time-release stuff i think

Ammended with perlite or aerator? perlite

Do you check pH? nope; i will do that next time i water tho

Have you watered? yes a couple of times, one of the times i used tap water by accident (pH of 7.4)

What was the concentration of microblast that you foliar feed them? 5ml / gallon

Are the leaves wavy and twisty? Drooping? a couple of the ones that don't have the rust spots have some wavy leaves, but they're green and healthy looking other than that

Temps and humidity? 75-80 F, 60 - 70 humidity

 

[presto]

the lorax wrote: the yellowing and rusting would come in from the tips if the plant ate from its roots

good point. any chance this could be a rust fungus?

 

[BigJilm]

It's not rust fungus--it could be but it is highly unlikely. pH problems, overfert, overwatering, etc symptoms all kind of look like a fungus
It sounds like overwatering to me. Mutiple waterings at 10 days is too much. Were they drench the soil get run off type waterings? Definitely overwatering if that is the case. I usually mix up my soil/ perlite mist it with a spray can and toss it around until it is moist throughout not wet--then put it in the cups. Couple more squirts right where the seed will be placed and put the seed in it. Lightly mist the top of the soil with the spray can every day--but my room is dry and I put a fan on them right away, so you have to base your mist watering frequency on your environment. Don't mist the leaves of a healthy seedling though.
I was a chronic seedling overwater on the first couple seeds I started. It's hard not to do--I think every soil grower had to have overwatered their first couple times. They can go 2 weeks without a full on drench watering--they need time to establish a root system.
I would also start them in smaller containers next time you start seeds this will help with overwatering. Are you using 16oz keg cups?

 

[presto]

yep, those red cups right?

yea i'm thinking about using the smaller styrofoam cups next time i germ some seeds. and ph could definitely be the problem, as i accidently watered with regular tap water one time.

also they were originally placed into rockwool. i think i should have waited for more roots to show out of the sides and bottom before burying them into the soil. i just did it when i saw one root poking out of the cube. so the cube would be drying out but the soil around the cube was still wet.