Plants not only need adequate water and nutrients, which they receive from fertilizer, plants also need oxygen. But not only above ground, but also the roots have to get enough oxygen. And that's why flowerpots must have holes.
Unfortunately this is not always the case. For example in the clay pots that people like to put on the patio or spread out in the garden. These pots should not be set up without a drain. So it's best to pay attention to this when you buy it.
Drill a hole in the flowerpot yourself
Unfortunately, such pots are often offered without the said holes. Then you have to take care of yourself. Turn the empty pot upside down and carefully poke a hole in it. This way the irrigation water can drain away, does not accumulate, the roots get air and the plant does not start to rot.
Alternative Clay Balls
You can then place a saucer under the pot if, for example, you don't have time to water it every day. This way the plant can help itself for a few more days. What you can do as an alternative: Line the pot with foil and put clay balls at the bottom to store the water. Then the earth on top. But the variant with the hole is better.