Lemons sprout easily from the seed found inside the fruit, but growing a lemon tree from a seed just because you can isn’t always smart. Growing lemons from seed isn’t a good idea as they don’t come true to type (that is the fruit may not be like that of the parent fruit), may be thorny, large and take a long time to produce fruit.
Lemon trees that are sold by garden centres are grown by budding or grafting. The selected variety is budded onto two-year-old rootstock. The rootstock is usually a variety known as ‘Trifoliata’, which is resistant to root rot diseases. Dwarf trees are grafted onto the dwarfing rootstock called ‘Flying Dragon’ which keeps them small and growing well in a pot.
If you want to go ahead and plant a lemon seed, then they are grown the same way as mandarins and other citrus. Sow several seeds and select the strongest plants to grow on into a new tree. Expect to wait several years for flowers and fruit.