Reaching my garden's potential

Well, contrary to what Betty says, the garden doesn't always reach its full potential.
Take my carrots, for instance. For the past few years, I've been having fabulous luck with Rainbow carrots, whose colours range from dark orange, through yellow, to white. They are sweet, delicious, and usually so plentiful it takes a day to harvest, wash, and store them. Not this year. When only a very few plants emerged long after planting two packages of seed, I went back and planted two more packages in July. No better luck the second time. I spent about $15 for seeds, and I have seven carrots.
When I planted sunflowers, the same story. I painstakingly planted a row of 10 seeds at the correct depth and the correct spacing at the correct time - nothing happened. I replanted new seeds and three lonely specimens appeared.

But the sunflower shown above sprang forth without any effort on my part. I didn't plant that seed. It's a volunteer, and where the seed came from is a mystery.

The garden's potential lies not in anything I do, but what happens naturally. In spite of my best efforts, things I plant thrive or die, and the power I have to control my garden is an illusion.