Nipping Dahlia tips

Hello fellow gardeners.

I would like to know if it is a good idea to nip the growing tips off when growing Dahlia's either from tuber or seed.If the answer is yes when should i do this, also would the plant become bushier.Please let me know.

thanks graham. 

I nip out the early flower buds on the taller ones to make them branch out-that might be in June/July??

Dwarf ones grown from seed do not need it.

thanks for the advice.