What Time To Practice
First of all I'd let to make clear that there are no wrong times to practice, the meditations can be performed at anytime and in any order. That being said traditionally there are ways to increase the efficiency of the meditation, these theories date back to the I Ching and have been used for thousands of years. To understand why different meditations may be performed at different times we need to look at two cycles that are used extensively within Taoism and Traditional Chinese Medicine.
The Meridian Clock
The clock opposite is used to understand where the energy is dominant in the body at a certain time of day. This information can then be used to find a more beneficial time to meditate when healing certain organ groups.
For example when using the Spleen meditation which is part of the Spleen/Stomach pairing the best time would be between 7am and 11am. For the Kidney and Bladder the best time would be between 3pm and 7pm.
Of course this approach can create a few problems, for example if you wish to concentrate on the Liver meditation it may not be advisable to stay awake until 1am just so you can heal the Liver. In this case we have another option. In traditional acupuncture the position on the clock directly opposite can also have an effect. For example rather than performing the Liver meditation between 11pm and 3am we could instead perform the meditation between 11am and 3pm. By adding this theory we double the amount of possible times available.
Opposite is a list of possible times for practice using this clock
Kidney: 3pm to 7pm or 3am to 7am
Liver: 11pm to 3am or 11am to 3pm
Spleen: 7am to 11am or 7pm to 11pm
Lungs: 3am to 7am or 3pm to 7pm
The Yearly Clock
This is the clock I personally use more often. The theory is based on the relationship of the seasons to each organ group, this information can then besuperimposed upon the times of day.
For example the Liver is associated with Spring, therefore practicing the Liver meditation first thing in the morning when you awake would be beneficial.
Opposite are the times of day most beneficial when using this system. Please note the Spleen and Stomach are slightly different. This is due to their position on the wheel which in earlier texts is in the centre. The centre position symbolically shows how important these organs are to overall good health.
Kidney: Late evening
Liver: Early Morning
Lungs: Late Afternoon- Early Evening
Spleen: This meditation can actually be practiced at anytime. Theoretically the energy's of Spleen and Stomach are present within all the elements and provide a foundation for them to flourish. As such the whole day is associated with this meditation.