To me, sadhana is a daily spiritual practice allowing time and space for an individual to turn inward.
As Yogi Bhajan (of the Kundalini yoga tradition) says, "Sadhana is self-enrichment. It is not something which is done to please somebody or to gain something. Sadhana is a personal process in which you bring out your best."
Sadhana could be taking a walk in nature, doing breath work or yoga asanas on a mat, spending time meditating or chanting, reading and reflecting on a poem, or simply watching the sun rise.
Please accept this post as a possible starting point for your own practice today.
Trilliums, by Mary Oliver
Every spring among the ambiguities of childhood
the hillsides grew white with the wild trilliums. I believed in the world. Oh, I wanted
to be easy in the peopled kingdoms, to take my place there, but there was none
that I could find shaped like me. So I entered through the tender buds,
I crossed the cold creek, my backbone and my thin white shoulders unfolding and stretching.
From the time of snow-melt, when the creek roared and the mud slid and the seeds cracked,
I listened to the earth-talk. the root-wrangle, the arguments of energy, the dreams lying
just under the surface, the rising, becoming at the last moment
flaring and luminous — the patient parable of every spring and hillside year after difficult year.