Hi, I am fairly new to gardening and live in central Florida near the east coast. I have potted three rounds of dwarf French marigolds and have followed all instructions that came with them however they always seem to die within the first few weeks of re-potting them. They were all purchased as young plants from a nursery, not seeds. I have used fungicide. I have kept them moist but not too wet. I used high quality potting soil. They get plenty of sunshine. I am not understanding why they don't make it as I have heard they are one of the most easy plants to grow. Any advice on what I may be doing wrong?

I don't claim any expertise on marigolds but they do grow well in poor-soil areas of my garden without any attention. The soil in your pot looks very rich and organic. Maybe it's too nice. Not all plants appreciate that, surprisingly.

Spider mites could be part of the equation. I don't know what killed your plants, but when spider mites kill a plant, it ends up looking like that.

That is a very good suggestion and something I have not thought of. Maybe a less fertile soil would help. I spray my ornamentals with Sevin so hopefully it is not spider mites but I guess you never know! I am going to try replacing some of the soil in the pot with regular garden soil and see what happens. Thank you for responding

I learned the hard way that marigolds do not like fertilize. Replacing your rich potting soil with something puny like peat moss might be a good idea.

Also, I just dug them up and the roots look good to me. How much water do you give your marigolds? At first I think I was over watering. So I cut way back on watering this time and it is still happening. Even the ones that are doing "ok" are still getting really droopy underneath

Is Sevin safe for marigolds? I have no idea, I don't buy stuff like that, but it seems worth checking.

Marigolds like it dry, maybe once a week watering, do your pots have drainage holes.

Yes my pots have drainage holes; I even drilled some extra holes. From what I am gathering, it is the nutrient rich soil I am using that is the problem. Go figure! And I did check the information label on the Sevin and it states it's safe for ornamental flowers but maybe it's not??? I really appreciate everybody's advice. I am new at this but so far really enjoying gardening

That all sounds good. Sometimes even when you "do everything right" plants just don't cooperate. Keep trying, maybe try marigolds from seeds, or some other different plant. Maybe a Cosmos if you want try try another yellow bloomer.
Sulphur Cosmos (Cosmos sulphureus)
There are specific yellow cultivars, if you want to avoid orange.

Need dryer heat, stronger sun, and look at a problem we southerners have called powdery mildew. Some seasons are just harder on marigolds and the humidity is a killer

About the Sevin...
You don't mention how you're applying the Sevin, or how often. I think the following is true for all forms of Sevin, quotes are from the Sevin dust label.
Sevin is not recommended for use on plants that are flowering. It is highly toxic to our friends the honeybees. It is capable of killing an entire hive. It is contributing to colony collapse disorder. If your marigolds have flowers, you should not be using Sevin on them.
Sevin is not recommended for areas where residue will run off into waterways. It is highly toxic to aquatic life.
Label directions include this statement: "Some phytotoxicity may occur on tender foliage in the presence of rain or high humidity of several days duration following application." "Phytotoxicity" means damage to plant tissue.
Label precautions state: "Begin applications when insect or damage is first observed." Like most pesticides, it should not be used as a routine preventative.
Label also states: "Do not repeat application more than once weekly or more than six times per year." Again, repeated applications are not recommended.
Sevin is an insecticide. It will kill any predatory insects that feed on spider mites. It will not kill spider mites. Killing off the predators can lead to a spider mite outbreak.
So, if :
Your plants have flowers
Run off from your property enters waterways
You have rain or high humidity after applying Sevin
You are not seeing insect damage
You do not know what insects are causing damage or if they are susceptible to Sevin
You think you might have a spider mite problem
THEN you shouldn't be routinely using Sevin! The Sevin could actually be contributing to the death of your plants, not to mention the damage it does to honeybees and aquatic life.
I am not opposed to proper use of insecticides, but please read and follow label directions. And, only use them if you have identified a specific problem you are treating.
Also, again, insecticides do not kill spider mites.

That is all very good information about the insecticide. I originally bought it because I was having major insect issues with my knockout roses and caterpillars were devouring my Lantana and SunHostas. Then I saw some "spider webs" on my marigolds and some of my other plants. I was not sure what exact type of insect it was from so I sprayed those too. I think I will not use it on the marigolds again. I started out using just neem oil but that was not very successful. Do you know of a good insect repellent for flowers that will not harm the bees? Another battle I am having is with fungus, as I am in Florida and it is extremely humid

If I see pesties on a beloved houseplant, I spray rubbing alcohol and that has done the job.

Outside, I don't get involved beyond manual measures like physical pest removal, re-location to a weedy area, trimming the part of a plant where most of the action seems to be located, moving things around, getting more of that plant so there's enough for me and the pesties - at least until their predator finds them and takes care of business. For every pest, there's something that wants to eat it. Poisoning their dinner seems like the wrong thing to do to me. Sometimes the predator needed doesn't show up as immediately as I would like, but there are thousands of critters out there and I don't feel qualified to get involved in their adventures just because I was trying to grow a few pretty plants - which attracted the insect activity. I can get more plants, but we only have 1 nature out there.

Sometimes a particular plant just doesn't do well so I find something else to replace it. There are so many choices.

That may not be the kind of info you're looking for, but it's one perspective to ponder.

I am realizing that I have to accept what WILL grow here, not necessarily what I WANT to grow. Gardening is a new venture for me so I am learning these things along the way. Thank you for the advice

Marigolds draw spiders, they are the beneficial in that case. The French marigolds are what are considered to benefit and protect other plants, the spiders drawn to them are after pests, or whatever else is drawn to those plants. Here in the south we have what is considered the Mexican Mint Marigold, though it is tall and seems to bloom in the fall for me.

Jenunruh, I am always happy to hear that someone is getting into gardening, and asking good questions about how to succeed. There are many different ways to garden, and different reasons too.
I've never used anything stronger than insecticidal soap on outdoor insects, and not very much of that. So, I'm not the one to recommend an insecticide nor a fungicide.
There are, however, some general pest control principles I'd like to share with you.
First, look for plants that are disease and pest resistant.
Learn to tolerate some damage.
Always identify the pest before treating. You don't want to wipe out the pollinators, butterflies, pest predators, and the beneficial mycorrhizal community (among others).
Cultural and mechanical practices can go a long ways.
If you do decide to use a chemical treatment, look for the least-toxic choice.
Again, make sure you have identified the pest you are dealing with, then choose the least-toxic alternative.
Always read and follow the label directions.
Here's a link to some information from University of Florida Cooperative Extension:
https://sfyl.ifas.ufl.edu/lawn...
(Get acquainted--they're a great resource.)
Ask Big Questions!
Here, marigolds are generally grown as annuals. Plant them in the Spring, enjoy through Summer, they will die in the Fall. Relax, treat them as annuals, and find what else does well for you.
Happy Gardening!

As a fellow gardener in high temps and high humidity, I hear you, Jenunrah! This thread has been great for learning about Sevin dust. I would also like to add a wonderment to your original question about the type of potting soil you're using. For example, I have found that the bagged soil with "moisture retention" beads are a death knell to a lot of plants, as they keep the soil weirdly moist, which in turn, causes fungus, and then the plant dies. Just wondered if that's what you used originally?

Do NOT add soil from your garden to the potting soil. It makes it even more moisture retentive. If anything, add fine orchid bark or perlite to reduce water-holding capacity. When you water make sure that plenty of water comes out the bottom so you know all of the soil is wet. Marigolds do great if you plant them 1/2" or so deeper than they are in the grow pot. They develop roots on the stem that is buried. From what I can see it looks like yours are planted to high. When you plant them, tamp the soil down firmly to make sure all the roots are in contact with the new soil. Here we water almost every day in the summer and 2-3 times a week if it gets cool and doesn't rain. Fertilizing according to label directions is fine. I use a bloom-type food for maximum flowers.

Jenunruh,
I live in Minnesota, and the last 2 - 3 years my potted marigolds thrived, then by August started turning black on the leaves. Meanwhile, the ones I sunk directly into the ground thrived and turned into small mountains! All the same variety! I never feed them, I always deadhead them. I do think it's connected to too much rain/watering. Hang in there...marigolds are such happy flowers!!!

This is all great information. The soups I used was Miracle Gro potting mix (the yellow bag). I must have potted twenty different marigold plants at three separate times of the year and none of them ever make over a few weeks. From what I am hearing they are getting too much water. The roots look good; if I replant them in different soil do you think they could come back?