In the long run natural plant foods are actually less expensive to use. I have trouble growing a nice garden because my soil is so bad. Natural gardening is actually a technique of feeding the soil so the soil can feed the plants more effectively. Your garden will soon be able to support an abundance of healthy plant life. I always have some kind of pest or disease problem on my garden plants, and I buy a lot of pesticides to control them.
Chemicals just kill everything.
By enhancing the biological diversity in your garden with natural practices, you will be including the natural enemies of these pests. In the soil, you will be promoting the vigor of billions of beneficial microscopic organisms that actually crowd out and sometimes-feed on disease causing microbes and pests that live in the soil. I hear so much about compost and mulch these days. The addition of copious amounts of organic matter to the garden in the form of compost and mulch will improve the soil, save you money on watering, and will promote the growth of many natural garden helpers like earthworms and disease fighting microorganisms. Compost and mulch are also the very best way to form humus in the soil.