Ritucharya for all seasons is divided in 3 parts – commencement, maintenance and withdrawal from the seasonal practices. Sandhikal is the time joining the beginning of the ensuing season and simultaneous withdrawal from the previous season. So in Sandhikal the health practices of the previous season should be gradually replaced by the new seasonal health practices, without giving a blow to the stability of the body in the form of diseases, due to the change in seasons.
Sandhi means connection or link. Sandhikal is the time of joining of 2 seasons and therefore beginning of changes in climatic conditions.
Sandhikal is the vital period of Ritucharya, because it is the time of seasonal transition. The body is weakest and more vulnerable to the disease causing factors, as most of its energy is focused on making adjustments to ensuing season.
For example, the body system is tuned for hot weather in summers, the blood vessels are dilated and large amount of heat leaves the body via skin through evaporation. But if the body is suddenly put in the cold weather, in the same physical state, it will lose heat profusely until it makes hasty physical corrections, like shivering etc. Changing seasons repeatedly expose body to such physiological shudders. This is a simple example, but there are so many complex processes that help the body tune itself to the outside environment. Even small changes in the weather or food might have immense effect on an unprepared body. By the grace of nature, the natural changes of the seasons set in gradually, giving a healthy body adequate time and resources to tune itself to the new season. If the weather changes suddenly then it causes more diseases, as the body is unable to adjust to the sudden changes.
The far reaching impact of Sandhikal is not the minor ailments. The actual impact reflects on the aging process of the body. For example if you are used to applying brakes of your vehicle suddenly , the age of the brakes will not be much as compared to the ones which belong to the people who habitually slow down before applying the brakes.
The food and lifestyle should start to change with the beginning of Sandhikal, for effective prevention of diseases and aging. There are 6 seasons according to Ayurveda and each season is roughly of 2 months. So we can understand that the 1-2 weeks of the ongoing season and the 1-2 weeks of the coming season constitute the Sandhi kal.
Sandhikal duration of total 1 month, including the seasonal start sandhikal and end sandhikal, gives the body adequate time to prepare. For example Sharad starts from 21/22nd Sep to the end of Nov approximately; in the Hindu calendar months of Ashwin and Kartik. The previous month is Bhadrapada, which contains the last 1-2 weeks of Sandhikal for Sharad and Varsha (rains).
The aim of Sandhikal Ritucharya is to make appropriate and quality resources available to the body in terms of food and lifestyle, which will help it to adjust to the ensuing season, without falling sick or getting weak.
Also, we should consider differential sandhikal for different people, the standard sandhikal being of first 2 weeks and the last 2 weeks of each season. That means approximately 1 month in a season of 2 months duration will be sandhikal. This way sandhikal becomes more inclusive for the weak, old and diseased people, whose body metabolism adjusts more slowly to the changes than a normal healthy young body.
There are 6 sandhi kal for 6 seasons and they form a cycle together with the seasons.
Hindu calendar is Luni-solar calendar. Solar calendar and lunar calendars differs in their months. The solar calendar is the duration of the earth’s rotation around the sun. Solar calendar has 365 days in a year. Lunar calendar is the duration of the moon’s rotation around the earth and it has 354 days. Therefore there is a gap of few days between the solar and lunar months. In the picture above, the days of vasant from Mesha Sankranti to Vrihabha Sankranti, form a solar month of Mesha, where vasant actually starts according to solar calendar. Solar calendar is considered more appropriate to calculate the seasons. Therefore we can consider the first few days of Chaitra as the later part of Sharad sandhikal. Each Hindu month has 2 phases, one waxing moon (brightening) and other of waning of the moon. For easy understanding, let us take 1st day of the month as the beginning of new season, for example 1st day of Chaitra month is the start of Vasant (spring) and last day of Vaishakh is the last day of Vasant.
Also sandhikal for a season has two parts: ascending and descending. For example Sandhikal between Vasant and Grishma is from 14th May to 14th Jun. In the first half of this duration, the focus is on decreasing the Vasant Ritucharya to a normal level, the second half focuses on increasing the Grishma ritucharya. For example Kapha purification processes and use of wine should end after around 30th Jun and the use of Sattu can be started by the first week of June.
These Sandhikal are converted to the form of cultural festivals to encourage the crowd to follow the procedures with enthusiasm, as it is said…happiness is the basic sutra to health. Every corresponding festival has traditional dish or a ritual to mark the beginning of change, for example Makar Sankranti has tradition of making Laddus of Lentil seeds. This tradition of making and eating Til (sesame seeds) laddo is also an Ayurvedic preventive practice. Til mixed with jaggery is a hot temperament combinations which effectively helps in exodus of access Kapha accumulated in the body. This festive falls in the Sandhikal of Hemant (Fall) and Shishir (winter)
Body Cleansing is an important factor of Sandhikal and fasting is the most convenient, natural and economical way to do it, but there are exceptions to the rule. Fasting in Sharad is unique as it should never be a complete denial of food, since the digestive fire is very strong and it burns the body substance (Dhatu) if it is not satisfied with adequate food. Under eating in this season is more dangerous than overeating. This increased digestive power is referred as the fire in the fireplace, flared by the wind, if not satisfied with enough wood, will burn the house down.
Please find a table of Indicative Health Habits during the Sandhikal of seasons –