Help with black spots on basil leaves please

[Akasa]

Hi all, I was hoping for some advice about my basil plant's leaves developing some little black spots. Our indoor basil plant had some aphids destroying it so four days ago I gave it a decent spray with Nature's,Way Pest Spray (active ingredient potassium salts of fatty acids). Since then all the bugs seem to have gone but my basil leaves have developed black spots, especially on the lower leaves (pictures attached). I don't think it's overwatered, if anything we're very careful to water only every few days if the soil feels dry because we previously killed a plant with overwatering. Our basil plant lives next to a window, we're in Australia and it's currently a rainy summer. Any advice as to what is causing this and how to fix it would be greatly appreciated. Thank you in advance!

 

[Marck]

Greetings, welcome to the Forums.

This is a bacterial leaf spot that Basil (Ocimum basilicum) often gets in humid conditions.
If possible, grow your basil outdoors in full sun in a place with open air flow. Ideally, out of the rain, such as on a sunny porch.
If the basil must remain indoors, still do what you can.
Remove all leaves with black spots and dispose of them. Continue to do this daily.
Also, remove dead leaves from the soil surface and mulch the soil surface with a fresh wood chip mulch. Sand or pebble could also work.
When you irrigate, try only water the soil surface and keep the leaves dry.

 

[Akasa]

Thank you Marck, will follow your advice. Fingers crossed!

 

[akhileshmaurya68]

Hi,

I know one solution for this kind of bacterial infection that may work. Use neem oil or margosa oil for disinfection.

Regards

 

[Akasa]

Thank you. Will also give that a go if the black spots worsen !

 

[pionjane]

Is growing basil very problematic? I've heard that this herb is very picky

 

[Marck]

Is growing basil very problematic? I've heard that this herb is very picky

Not always. Often basil does fine in the right conditions.
Another thing I should emphasize more is crop rotation. Don't grow the same annual crops in the same bed or container year after year.
Growing the same crops in the same spot allows pathogen levels to build up higher than they would otherwise.

 

[pionjane]

Not always. Often basil does fine in the right conditions.
Another thing I should emphasize more is crop rotation. Don't grow the same annual crops in the same bed or container year after year.
Growing the same crops in the same spot allows pathogen levels to build up higher than they would otherwise.

Thanks! You've given me confidence. I think in the next month I will start growing basil.

 

[Ruderunner]

I don't think basil is picky at all. I usually get 3 inch seedlings on memorial day and by September I have shrubbery. 3 feet tall and 2 feet around. This is outdoors.

We have poor results growing anything indoors but have come to the conclusion that our energy efficient windows block too much uv for indoor plants.