The answer really does lie in the soil. Good soil means less work and less frustration with poor results.
The best soil improvers are those based on organic matter. Not only do they increase the water and nutrient holding capacity but they also provide the raw material that supports life in the soil. This generates a healthy soil that in turn promotes healthy plant growth. Getting the soil right is the key to healthy plants with minimum resources. Conversely, if the soil is not right, gardening can be a constant, frustrating and expensive struggle.
...feed the soil and let it feed your plants...