The supermarket giant has extended the deadline to August 19, and has strongly urged Dobbies Shareholders who have not yet accepted its offer to do so 'as soon as possible'.
The news comes after yesterday's second deadline where Tesco claimed the support of 32.6% of the garden centre chain's equity.
Tesco's offer of £15 a share, requires the support of more than 50% of Dobbies shareholders to succeed.
All eyes, however, remain on Sir Tom Hunter and his 25% stake.
On Monday he received a 'put up or shut up' ruling from the UK's Takeover Panel, requiring him to bid for Dobbies by 5.00 pm today or be barred from doing so for six months.
According to financial news service Hemscott, Dobbies share price closed yesterday at 16.52, well above Tesco's offer at 15.00