I generally sow mine in spring,but last year I tried autumn sowing............never again......too much hassle in spring when they start growing again. Plus I had a poor crop this year but I won't put that down to the sowing period, more likely the abnormal weather this year.
The reason I like sowing in spring is; they can be grown without a 'check' and mine seem to respond to this treatment.
So I think it is simply a case of what suits you best..... do!!