One verse

Srimad Bhagavatam 4.8.73

4.8.73

द्वितीयं च तथा मासं षष्ठे षष्ठेऽर्भको दिने । तृणपर्णादिभि: शीर्णै: कृतान्नोऽभ्यर्चयन्विभुम् ॥ ७३ ॥

dvitiyam ca tatha masam sasthe sasthe ’rbhako dine trna-parnadibhih sirnaih krtanno ’bhyarcayan vibhum

dvitiyam
the next month
ca
also
tatha
as mentioned above
masam
month
sasthe sasthe
every sixth day
arbhakah
the innocent boy
dine
on days
trna-parna-adibhih
by grasses and leaves
sirnaih
which were dry
krta-annah
made for his food
abhyarcayan
and thus continued his method of worship
vibhum
for the Supreme Personality of Godhead.

In the second month Dhruva Maharaja ate only every six days, and for his eatables he took dry grass and leaves. Thus he continued his worship.