This Friday night is Seder night. But don’t panic, you do not have to clear your house of chametz before nightfall. It's Tu B’shvat, and one of the main traditions of this festival is to bring spirituality to the dining table in the form of a seder focused on new fruits.

The Tu B’shvat seder originated in Safed, Israel, in the 16th century with the Kabbalists who lived there. An anonymous student of Rabbi Yitzchak Luria (1534-1572), the greatest Kabbalist of Safed, was the first to write about the tradition of eating particular fruits in a specific order and reading passages appropriate to each of them. Over time, different communities have added their own customs and the Tu B’Shvat Seder has developed into a unique expression of appreciation for the land and its produce.

It is divided into four parts, with each section representing one of the four seasons. We drink four cups of wine and we change the colour by progressively adding more red wine to correspond with the changing seasons.

Since this year Tu B’Shvat is on Shabbat, we must be careful not to transgress the biblical command of not dyeing or colouring on Shabbat. Therefore, when mixing white and red wine, we should pour the red wine first. In addition there is the ritual consumption of different types of fruits and nuts.

We begin our Seder in the traditional manner, by asking four questions designed to help us understand the significance of this day. Here are some examples.

Our other holidays honour events and people. Why does this holiday honour trees? Ordinarily, we eat whatever fruit is in season. Why, today, do we specifically eat fruit that is grown in Israel? We usually take the environment for granted. Why, today, do we focus on conservation? It is winter. Why are we thinking about planting when spring is months away?

And as you would expect, the answers reveal a lot about our relationship with God and the world around us.

We honour trees because we want to celebrate our commitment to serve and protect the trees, and all of God’s creation.

In addition we have the Law of Orla which states that one not must eat the fruit of the tree in its first three years and, in the fourth year, called Revai, we can only eat the fruit in Jerusalem or redeem it with money and spend that in Jerusalem on food.

The first cup of wine is white, representing winter, during which the fruits (nuts like hazelnuts and walnuts) are covered by a shell — as the ground is covered by snow.

And we eat Israeli fruit to support the original purpose of Tu B’Shvat, which was to mark tithing responsibilities. However, today, for some, it is also about supporting Israeli produce and showing solidarity in the face of the boycott campaign.

The second cup of wine is meant to be rosé — or red wine mixed with a majority of white wine. This represents spring.

Fruits that match with this season generally have hard inedible pips or stones. They include peaches, plums, nectarines and apricots.

Our answer to the third question, about the environment, reflects our long held connection with nature. In the Jewish religion we do not need complex conferences and scientific papers on climate change to realise the impact we are having on future generations.

The third cup is white wine, mixed with a majority of red wine. This represents summer and includes fruits which are edible in their entirety, like apples, grapes, pears, raspberries, blueberries and strawberries.

Fruits are so valued that the Torah commands us to leave fruit trees standing when we attack a city in wartime.

The fourth cup of wine is pure red wine and this represents harvest time. In this section, no fruit is eaten. Rather, we rely on the power of scents from herbs and spices such as rosemary, mint, herbal teas etc.

Some communities have a custom of eating 15 fruits corresponding to the 15th day of Shvat. Others consume 12 different fruits which correspond to the 12 tribes of Israel.

As well as incorporating lots of tradition, the Seder also has a modern angle — eating seasonal food is back in fashion, at least among Britain’s middle class, and is recognised as ecologically sound.

Seasonality reduces the energy (and associated CO2 emissions) needed to grow and transport the food we eat. It — at least theoretically — avoids the need to pay a premium for food that is scarce or has travelled a long way. It supports the local economy and, crucially, it reconnects us with nature’s cycles.

Perhaps importantly, seasonal food is fresher and so tends to be tastier and more nutritious. Fresh English strawberries in June cannot be compared to the tasteless overseas varieties in December.