250W HPS will put out enough lumen to successfully grow 1-2 plants.
To keep plants short a SoG or ScRoG method are best. If you wanna respect the KISS rule (Keep It Simple, Stupid), a LST or supercropping method works fine too. This info may also prove useful: if plants are kept at 24/0, they will grow bushy and less tall, if kept at 18/6, they will strech and grow tall.
But the easiest easiest way of keeping things short is getting a very dominant indica - my recommandation: White Rhino (will never grow over 70cm/2,3 feet) - or flower early or even 12/12 from seed if you have a sativa that would otherwise grow well into your upper neighbours living room (like, 3-4m height).
Never ever buy soil with that slow nute release crap (like Miracle Grow soil). This will only lead to nute burn and the ratios of NKP in this type of soil is terrible for vegging or flowering. Buy simple potting soil for flowers with a pH between 6 and 7 ideally, but never over 7. Some perlite will really come in handy. Soil/perlite ratio should be 60/40 to 80/20.
Soil growth is great, easy and affordable. A hydro grow would not be easier and would cost more money. Many say plants grow slower in soil but if done right they can produce just as much yeald as a hydro grow in the same amount of time.
