Breath is an ever-present aspect of life, which is part of the reason why "mindfulness of breathing," or ānāpānasati in Pāli, is probably the most common form (object) of meditation. Typically, the practice involves focusing attention on the physical sensations caused by the movement of the breath, the in-breaths and the out-breaths. Mindfulness of breathing is a feeling practice, not a thinking practice. It's so profoundly simple that we can do it at any time, whether seated in meditation, holding a yoga posture, or picking up after the dog.
Yogis, meditators, mindfulness coaches, Christians, and countless other spiritual seekers commonly employ the metaphor of the garden to represent stewardship. To view the mind as a garden is to view it as a place with potential value and commit to cultivating it. One must locate the space and make effort, which can take a variety of forms. One can tend to the garden of the mind while doing yoga, meditation, or any other activity in life.