In gardening you're trying to grow plants. The plants can be fruits, vegetables, ornamentals. You may grow them for their practical benefits, their aesthetic benefits, or for their emotional and spiritual benefits.
You prepare the ground, loosening it, aerating it, amending it with organic matter and fertilizers in order to prepare a space conducive to plant growth. You plant your seed, set your seedling, or seat the bulb.
As the plant grows you periodically feed it with fertilizers appropriate to it's stage of development. You make sure it gets enough water. You protect it from too much sun, too much heat, not enough warmth. You keep pests from it by proper use of insecticides, companion planting, or physical means. You weed regularly so the plant you are nurturing doesn't have to compete too much with nearby plants for the nutrients and moisture it needs.
And you watch.
If you've given the plant an appropriate environment, it will grow hardy and colorful, wending it's own way into the light, until at maturity it provides it's fruit, seed, leaves, or flowers for your pleasure. You've started with a seed, and from what is inherent in the seed maturity comes, but in a form unforeseen except that you knew you would end with fruit or a flower.
We've all seen, and if you're like me, have had, gardens that are nothing like what was described above. Fertilizing and watering came catch as catch can. The sun wilted the young growing plant. Insects blighted it's growth. Birds, more observant than you, ate the fruit at it's peak of flavor. Weeds overran everything, choking out the bounty that you so looked forward to when in the spring you first prepared the ground for your harvest.
We're not much different.
Look around. Watch the news on television. Observe the members of your family. Look in the mirror. How often do the weeds take over our own lives?
In personal development your own being is the seed you are nurturing. All that you are already exists at the moment you take your first breath. When you are young, you may receive the proper nourishment for the development of a hardy, creative self - or you may not. The garden of your self may be choked with weeds, shaded by the past, and fed with candy rather than food.
But as you get older, you take over the maintenance of your own garden. You can seek out the food that will nourish you over the long term. You can weed the habits of sleep and unconsciousness in order to let your true self stretch forth. You can clear the ground of your mind so your true self can grow unimpeded. You can plant companions of habits that keep away the insect invasions of anxieties and fear that keep you scrawny and small.
Your true self doesn't have to end up choked out by the weeds. But... you need to wake up and begin to be the gardener of your soul.