They can be but they will not survive.
Cacti would have to be planted in pots and moved indoors during cold, wet weather or planted in a heated greenhouse.
Pepper plants can only be planted when there is no chance of freezing weather or frost.
The size of the plant to be planted out is not important if well grown, in fact the bigger the plant the quicker it will fruit, however the weather conditions must be suitable.
The different types of weather and climate it is outside
The different types of weather and climate it is outside
By the shape of their leaves, also you would have planted in rows, plants outside the rows will be weeds.
Yes, you can plant amaryllis outside in your garden, but they are typically grown as indoor plants in most regions. In warmer climates, they can be planted outside in well-draining soil with partial sun.
Cyclamen can be planted outdoors. They are hardy plants and can withstand cold winters, and even snow. Plant these plants where they have a buffer, such as near shrubs, trees, and buildings.
Ferns
Corn and most other plants are generally planted in dirt.
In a pot.
it depends on how it is planted. plants growing outside tend to be stronger than plants growing inside. also it depends on how long u let it grow. but in an educated guess id say about 6 feet outside 4 feet inside.