Basil plant indoor getting dry and weak

I have 5 Indian basil plants in pot with organic soil
It was all good but now suddenly they start dying I have many plant flies in that pot not sure that is reason or weather I am in Chicago area but plants are inside. Please help. Photo attached you can see one is started getting weak and one is already down. I have added pebbles on top layer to get rid of flies but no help. Still they are there.

Hello!
You should be able to grow basil indoors regardless of climate, so the simple fact that you are in Chicago shouldn’t be a problem.  

Where do you keep your plants? Are they on a drafty windowsill or by an unsealed window where the temperature might be too low for them to be comfortable?

Did you have them growing outside and then brought them indoors? Sometimes they can experience ‘shock’ from a sudden temperature and light changes and lose their leaves before recovering.

You mention ‘plant flies’. That’s pretty vague, but I would bet you have the tiny, pesky, black gnat like flies that hover just above the soil. In my experience that is tied to soil that is either contaminated or much too wet for your plant. Is there adequate drainage in the pots? Basil doesn’t like ‘wet feet’.  Your attempt at a cure by placing pebbles on the surface of the dirt may compound this problem as it will help retain moisture in the pot. I’d remove the pebbles and put the plant in a non-direct sunspot in your house. This will help to dry the soil a bit.

Check for any little webs or bugs on the underside of the leaves. IF you find any, you can dip your finger in Neem oil and put it on the edge of the plant pot to kill/repel the bugs. Neem oil is safe and natural. IF your plants weren’t so small and struggling, it would be safe to use diluted with water directly on the plant. I’d keep it on the pot for now since they are not healthy.

If your soil is contaminated, you are best to repot with new soil, but beware that your plants may not survive if they are already weak. In the picture I see one small young plant and one tiny one that looks like it is dead in the pot. BE sure to remove any of the dead plants as the dead organic matter will draw more flies/gnats.

I see in your pot you have a small jar that looks like a fly trap with maybe vinegar in it? I’d take it OUT of the pot…put it about 8-12 inches away from the pot to draw the flies away. I fear that your method is keeping the flies right where you don’t want them.

Lastly, I think you are saying you have several potted plants, but this one is problematic, while the others are doing well. IF that is the case, I’d simply get rid of the problem pot altogether (throw soil and plants away). If you have any kind of contamination, it could spread to your other plants.

Good luck, and I hope this helps!

Thanks for your reply i have removed those pebbles and also cleaned once layer of organic soil, it was vary moist and now days no sun so i arranged a little warm light at distance to simulate sun, I hope it should work. Thanks!!

I use a ruby red heat lamp about 6 feet from the plants to extend the season in my unheated greenhouse. They seem to like the infrared heat. The air temperature is too cold now so they have gone to seed and turned brown. The tomatoes however have continued to ripen.  A tall pot with water wicking up from the bottom seems to be there favorite so that there is a warm dry surface and deep water so they don't get stressed. Lack of water seems to stimulate early blooming. Depending on whether you use the leaves or blossoms or both.

I agree, sounds like fungus gnats and too much moisture can make them worse.  One tip I have is to set up a humidifier on a timer, indoor environments are a lot drier than the outdoors,  This can also help you worry less about under-watering, since they are getting a little bit of moisture every day.  I have the timer set to 30 minutes mid morning and it has been working for me.