obviously you'd have much better result starting inside but I guess you don't need to hear that again or you would not be posting. As far as starting them directly outside I have done that too a few times. My advise is to prep the entire planting spot good, then remove a row of dirt only about 2" wide and deep and replce the dirt with high grade potting mix. Sow the seeds just like 1cm in the potting mix. Make them maybee 16" apart assuming you will kill off the males before finishing them. Don't water them or anything. Wait for the spring rains to germ them naturally. Get the seeds in right away like yesterday or ASAP past the last freeze date. Once they start growing up to about 6", remove competing weeds and add some landscape fabric around each one. Carry in a little water when and if you can during any real droughts.