The following can be said about the paragraph:
Although all sentences are written with correct spelling and grammar, they are all misplaced, which makes the paragraph chaotic.
After organizing the ideas, it would be necessary to use connectives so sentences could be linked, creating a better flow.
Punctuation could also be improved, particularly when there is enthusiasm involved, and an exclamation point would come in handy.
The paragraph could be rewritten in the following way:
It is unfortunate that many people feel too busy to garden, since there are many things to gain from working with plants outside. That's why I believe more people should take a chance with gardening to see what they can create. Plus, gardening offers more than a way for kids to have fun as well. I myself am glad I learned to grow plants when I was a kid! In fact, growing flowers is one of my happiest childhood memories!