Had to look up how many tablespoons of baking soda are in 100 grams. There are 21 grams per tablespoon (at least according one site I looked at, others have it lower at about 15g/1T.) which means you used at least 5 tablespoons in a mere 1 liter of water. That amount is staggering. Had it rained it would have washed all the baking soda off anyway so it was pointless to apply it in the first place. Only advice I can give is that you should wash off what you can and hope for the best. And next time be aware that any home remedy can do much more damage than what it's meant to prevent.

Rodney

Hello theforgottenone1013. thank you for your aswer.
And can I wet tomato the plants? I was told to NEVER wet the leafs

While it is advisable to avoid wetting the leaves when possible they obviously do get wet when it rains and do just fine. In this case I don't think you have any choice but to do so and hope it helps some.

As Rodney said, it wouldn't have done any good anyway as mildew (a vague catch-all term for many diseases that all have different causes) is not caused by rain to begin with and if present, has very specific treatments available.

You have learned a valuable lesson about when to listen to advice and when to just nod and then ignore it.

Dave

Baking soda isn't a good idea imo. If it is a strong solution and there are even powder residue on the plant, you should continue to see your leaves burn even more. Just pinch the dead leaves and let it continue to grow. When I started gardening I used it and ended up burning all leaves and killing the plants. Even the alkalinity of it is too strong when it run off and seeps into the soil changing the soil pH. I do use Safer Brand's Sulfur sometimes. Sometimes it's better to just leave the plants along if they're healthy.

There are lots of diseases in Florida and my plants are more likely to catch diseases after rain, more often the smaller seedlings. It's inevitable, but a plant with healthy root system and healthy soil is more able to resist. Mulching around the base of the plant to prevent the leaves from touching the soil also help. These aspect are more important than trying to keep the leaves dry imo. The fungal spores will find your plant eventually even if dry, or a diseased soil will get to it.

Imo, it's not a good idea to take advice from someone who make too much of a definitive sweeping statement, like NEVER this and NEVER that. I worry too much about little things when I started gardening as well, sometimes it's counter productive to do more for the plant than it need.

Yes, the moment I came home and saw the black spots on the leafs I knew I have learned a big lesson!
Thank you so much for your help!! So, I've washed all the plants with water and there aren't any white spots anymore. So, I have a few questions:

1) Should I cut off the blacked leafs or just leave them?

2) How do I need to wait to I know if my plants are going to produce tomatoes or not?

3) Do you think my plants will be OK? Should I go to the gardening center and buy new plants?

How long depends in part on your location and climate. Best guess - within a week you should see new healthy growth on the plant. Any severely damaged leaves should fall off or be removed within that same time.

In the mean time you can do some research into the 2 primary forms of mildew and learn about their symptoms and recommended treatments so you will know in the future. Google 'Downey Mildew' and 'Powdery Mildew'. But also keep in mind that in most of this country they are not the primary disease threats for tomato plants.

Common Tomato Disease Identification Keys and Controls

Dave