First, we need to understand the difference between compost and fertilizer.
There are two approaches here. Fertilizing your plants is often understood as giving your plants “vitamins." Adding composted material to your garden bed effectively means feeding the soil. A third thought might be to do both.
A lot of questions come to mind. Is one approach better than the other? What are the benefits of one verses the other. Is one more expensive? Is one healthier? s one more widely used and if so, by whom?
Before we can decide on which method we might want to use, we should know what each approach does.
Using fertilizer attempts to balance the elements N, P and K (nitrogen, phosphorous and potash). Certain types of plants use one of these elements more heavily than the other. Plants need nitrogen to produce their own food. Nitrogen develops a darker green color in plants. For a plant to produce healthy flowers they need an optimum amount of phosphorus. And, potash promotes a healthy root system.
Grass aka turf does not need to bloom, so the appropriate fertilizer would be more heavily balanced toward nitrogen. Flowers which are not intended to produced fruit or vegetables usually contain more phosphorous. Vegetable and fruit plants require a more typically balanced mixture of the three elements.
Adding compost to your garden soil works to enhance it in several ways. The decaying biological material in compost works to add beneficial bacteria, to loosen up denser clay soils and helps sandy soil retain moisture longer. Compost can also help to create air pockets (known as aeration) which become water storage spaces. Composted material slowly adds recycled plant nutrients back into the soil. And finally, compost can work to bring the PH level in the soil back from too acid or not acidic enough. In the range of 6.5 would be perfect for most vegetable gardeners. But if you wanted to grow blueberries, for instance, you would get a greater yield if the soil was more acidic, which is also recommended for azaleas and rhododendrons.
So the question becomes: Is one approach better than the other? And the answer would depend on your specific perspective. The truth is, your garden will become healthier with each succeeding year if you add compost and rotate the growing location of your vegetables. If you are patient, composting will work and cost less in the long run. If you have very little interest in studying what plants need, fertilizers may work to grow more and bigger vegetables. If you will be gardening for a long time, I would suggest you add compost to your garden on a regular basis even if you do use chemical fertilizers.
I have chosen to cultivate my garden without synthetic fertilizers. I am convinced that the consumption of synthetic chemical fertilizers and pesticides are connected to the cancer rate in this country. And, because my mother and one of my sisters have had instances of breast cancer, I choose to avoid synthetic agents when I can. When I need to amend the soil in my garden, I use things like compost, dolomite lime, gypsum and blood meal to name a few.
My favorite comment with regards to the compost verses fertilizer disagreement is this: One gardener’s big healthy plant might be another gardener’s overgrown monster. That gardener reminded me that younger vegetables are usually more flavorful than older larger vegetables.
So, as you can see, this is a question of perspective and priorities.