There are many reasons why we do gardening.... It's to protect and to produce more plants,gardening can be use for money and or because It's your hobby.
Organic gardening is the practice of growing fruits and vegetables without using pesticides and inorganic fertilizers. Sustainable gardening is gardening in a way that the soil will continue to be...
Flowers gardening, herb gardening at home, indoor gardening (plants, flowers, vegtables), vegetable gardening and so on...
You can find books about gardening at http://gardeningbooksplace.com/