when can the plant start to make its own food?

A plant always makes its own food. Ever since it existed it made its own food through photosynthesis. The leaves take in the sunlight and form it into food. It also releases oxygen.

Plants can start making their own food through a process called photosynthesis from an early stage of their life cycle. Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into glucose (a type of sugar) and oxygen.

If you're asking about the specific timeline for when a plant is capable of photosynthesis, it usually begins shortly after germination. Germination is the process by which a seed develops into a new plant. During germination, the plant embryo inside the seed begins to develop roots, stems, and leaves. As soon as leaves are formed, they can start photosynthesizing and producing their own food.

However, please note that the rate and efficiency of photosynthesis in a young plant may not be as high as in a mature plant. As a plant grows and develops, its ability to photosynthesize and produce food increases. This is why larger and more mature plants can sustain themselves better and have a greater capacity for growth.

So, to answer your question, a plant can start making its own food through photosynthesis shortly after germination, once it has developed leaves.