In a city where jostling for space is part of the daily grind, Mumbaikars hitherto had no inclination to invite the exotic fungus into their homes. Home-grown mushrooms were therefore the preserve of residents in cities like Pune and even Panvel in the state. Accustomed to cool climates and wide dark spaces, they are grown primarily in North India.

However, far from the idea tickling their tastebuds, Mumbaikars have begun to salivate over the lucrative returns the business generates. At a lecture-cum-demonstration organised by the Belgaum-based Patil Exports at Dadar recently, 80-odd persons turned up for tips on cultivating the delicacy, which included the largest contingent of persons from Mumbai ever.

Says A Srinivas, the company's Mumbai manager: ``Thereis a definite growing trend in Mumbai. We have been holding annual demonstrations here since the last eight years. This time, we were pleasantly surprised to see such a large turnout from this city''. Moreover, he says, the majority of candidates were from the middle-income bracket, which indicates that their interest does not spring from some exotic fancy.

Home-grown oyster mushrooms (button mushrooms need a colder climate) can fetch up to Rs 300 per kg when sold dried in the market. This does not require permission from the government and neither is income-tax payable. The minimum requirement is a 10 x 10 room and a temperature between 25 and 30 degrees Celsius.

The bed for cultivation can be prepared in two ways -- by the chemical or boiling process. In the first method, 14 kg of straw, 125 litres of water, 50 ml of formelyn and 7 gm Bavistin (pesticides) are mixed for 18 hours in a barrel. In the boiling process, straw is soaked for eight hours in cold water and then in boiling water for anhour.

The processed straw is then placed in an 18 inch x 6 feet polythene bag in several 4 inch thick layers and the seeds scattered between each layer. A bag of this size can accommodate up to 1 kg of seeds. The floor has to be covered with sand and the windows with muslin cloth. The room should be sprinkled with water at least thrice a day to keep it moist and maintain a low temperature. The bag is opened on the 21st day and sprinkled with water till the 34th day, when the mushrooms are in full bloom. One bag can yield almost 10 kg of mushrooms, which shrinks to one-tenth of their weight when dried.

Says A Srinivas: ``A 10 x 10 room can yield up to 20 kg of dried mushrooms at an investment of about Rs 100 per bag. A 2,000 sq feet flat can yield a profit of almost Rs 15,000 per month. Our clients sell them to us and forlarge out puts we offer to pick it up from their doorstep.''

Says Sadhana Talwar, a businesswoman who has been trying her hand at mushroom cultivation for the last two months, ``Tillnow, I grew them in small bags just to get the hang of the process and ate the mushrooms at home.'' Now, she has prepared almost 30 large bags in an empty shed behind her office at Thane's Wagle Estate for commercial sale.

Adds Srinivas: ``We have instructed almost 1,200 clients in Mumbai over the last few years. Most people who come to us are those who have empty flats and do not want to give them out on rent or those with a spare room or balcony. Some of them with hardly any room want to learn how to cultivate only the spawn (seeds) and sell them.''

His firm collects the mushrooms from its clients and then dispatches them to Coimbatore for quality segregation, from where they head towards wafer, soup and pickle manufacturers. The rest are exported to other countries.