Rust already?

I’ve had this occur constantly when plants go into flower but never this early. This is a sativa-dominant auto and I’m seeing it already. Any ideas about what it is will be welcome.


Spider Farmer sf-2000 led 200 watt
Fox Farms Ocean forest soil
Temp range 67 dark, 84 light
20 on, 4 off
For this early stage I’m using distilled water with a ph of 7. Would think the above soil has enough nutrients.

Should have plenty of food in that mix and it can often burn young plants but that does not look like nute burn but possibly low Calcium which seems odd too with fresh soil like that.

Distilled or good low ppm RO water has no real pH and can be considered neutral when watering your plants. It will not affect the soil pH either way. It's all I've ever used the last 20 years in DWC or potted plants.

I'd just keep an eye on it for now and if it doesn't seem to be getting worse as new leaves emerge than it could be just a break in period as the nute levels are most likely pretty high. I've seen a lot of peeps with fried babies using that stuff.