CC Madhya 24.261
nirantara kṛṣṇa-nāma kariha kīrtana
“ ‘After planting the tulasī tree before your house, you should daily circumambulate that tulasī plant, serve her by giving her water and other things, and continuously chant the Hare Kṛṣṇa mahā-mantra.’
This is the beginning of spiritual life. After leaving householder life, one may go to a holy place, such as the bank of the Ganges or Yamunā, and erect a small cottage. A small cottage can be constructed without any expenditure. Four logs serving as pillars can be secured by any man from the forest. The roof can be covered with leaves, and one can cleanse the inside. Thus one can live very peacefully. In any condition, any man can live in a small cottage, plant a tulasī tree, water it in the morning, offer it prayers, and continuously chant the Hare Kṛṣṇa mahā-mantra. Thus one can make vigorous spiritual advancement. This is not at all difficult. One simply has to follow the instructions of the spiritual master strictly. Then everything will be successful in due course of time. As far as eating is concerned, there is no problem. If Kṛṣṇa, the Supreme Personality of Godhead, supplies everyone with eatables, why should He not supply His devotee? Sometimes a devotee will not even bother to construct a cottage. He will simply go to live in a mountain cave. One may live in a cave, in a cottage beside a river, in a palace or in a big city like New York or London. In any case, a devotee can follow the instructions of his spiritual master and engage in devotional service by watering the tulasī plant and chanting the Hare Kṛṣṇa mantra. Taking the advice of Śrī Caitanya Mahāprabhu and our spiritual master, Bhaktisiddhānta Sarasvatī Gosvāmī Mahārāja, one can go to any part of the world and instruct people to become devotees of the Lord by following the regulative principles, worshiping the tulasī plant and continuously chanting the Hare Kṛṣṇa mahā-mantra.