This study describes the possible effects of tea residues on crop production. To investigate the negative effects of tea on two cereal crops, i.e. wheat and maize, laboratory experiments were conducted during May 2014 and repeated in June 2014 to study the effect of black tea extract on wheat and maize seeds’ germination and growth. The experiment was conducted in petri dishes and laid out in completely randomized designs, replicated thrice. The petri dishes were kept in a growth chamber, with the temperature set at 25°C. 50 g of each dried fresh and used black tea was separately soaked in 500 ml of hot and cold distilled water. The same amount of tea residue was soaked in 500 ml of methanol. Ten seeds of each wheat variety (Siran) and maize variety (Azam) were placed in each petri dish. 10 ml of each extract was applied to each petri dish according to the requirement. A control (distilled water) was used for comparison. Analysis of the data revealed that tea extract significantly suppressed seed germination and the growth of wheat and maize. Methanol extracts, on the other hand, completely inhibited seed germination. The negative effects of tea extracts on seed germination of crops warns that apart from polluting the soil, the crop production could be greatly affected by dumping tea waste in agricultural fields. However, used cautiously, the application of tea extract can be used to suppress the growth of weeds in agriculture.