Sometimes this is caused by slugs and snails which are often out at night or early morning snacking on plants.
Slugs and snails damage may be reduced by changing how you water.
Since they require damp ground cutting back on watering when possible can reduce their numbers.
It is common for landscapes to be over watered.
Most plants in most growing conditions do not need to be watered daily or even every other day.
Some other types of control: Beer or a mix of honey or molasses with bakers yeast placed in container.
I think this works best if placed in a bottle that is then placed at an angle to reduce the chance of rain or sprinklers diluting the mixture.
These will need to be checked often because of evaporation.
Iron phosphate slug baits work very well and are not harmful to people, pets, birds, or wildlife.
Sluggo and Escar-Go! are a couple brands I have used.
Nutribiotic (Grapefruit seed extract) mixed 5 drops per cup of warm water.
Spray on slugs and snails.
Nutribiotic may also help if drizzled around plants for a barrier.
After eating cantaloupe, watermelon, or grapefruit, place the rind upside down outside with the edge propped up.
Go out later and you should find many slugs or snails inside.
Barriers can also reduce slug and snail damage.
Small bits of hair (people or pet hair), crushed eggshells, sharp sand (not play sand) are all unpleasant for them and can protect your plants.
Diatomaceous Earth (also called DE) works as a barrier and a killer as long as it does not get wet.
Be sure to buy the garden type (not the kind for swimming pools) and read the label to be sure it is pure DE.
Copper sheeting at least 2" wide or copper wires placed 2" apart can also provide a barrier but is usually easier to install on pots, planters, or raised garden beds.
A Chore Boy could also be taken apart for this use.
Mint, lavender, and sage are herbs which are supposed to repel slugs and snails.
I have not tried this but I found a snail in my pot of spearmint so I wonder about mint as a repellant.
Mint will repel rodents and ants.
You could place some leaves or a spray of essential oil in water of either or both together around your plants and see what happens.
Ground cinnamon repels some pests and I have heard of success as a slug repellant.
Some people have had success with coffee grounds around plants.
That would probably be great in my area where the soil is alkaline but if your soil is acidic be careful about acidifying it even more - don't overdo the coffee grounds.
Tending your garden organically allows the natural predators of slugs and snails to help you out.
Some birds (including ducks and chickens), ground beetles, snakes, lizards, turtles, and frogs are some of the natural predators of slugs and snails so help them out by learning how to attract them and only using organic fertilizers and pesticides.
If you have chickens or ducks you may want to let them roam your garden or landscape once in a while to clean up for you.