Putting sativa seedlings outside in April at a northern latitude can push them into early flower because the days are still short, and then they revert to veg as summer arrives. The result is a stalled, oddly shaped plant that wastes a month recovering. The outdoor timing guide on Sativa Cannabis Seeds — THC, Height & Flowering Compared gives day length thresholds by region and suggests holding seedlings under supplemental light indoors until the natural day passes fourteen hours. Later planting with a bigger seedling almost always beats an early start with a small one.