You could grow them to a good size in 4 or 5 gal pots then transplant from that into the 20 gal holes I mentioned and they'll blow right up in the sunshine. If you veg at 18/6 make sure that you start reducing the hours of light 15 min every couple days if your timer will do that for a couple weeks before putting them outside so that you are at the same hours as daylight from a half hour after sunrise to a half hour before sunset for your area. Easy to get that info on the web for any spot on earth. If you take an 18hr plant and toss it out into a 14 hour day you could trigger flowering then it'll go back to reveg as the days get longer and set you back a couple weeks at least.
Should rig a shade cloth to cover them with from about 10am - 2pm for the first little while so they don't bleach in the mid-day sun until they get used to it. A week should be good. Hardens them off. Or take them out for a while each day going longer every day for a week.
Good luck and good growing!