Point of the matter is this. With 5kw , enough a/c to cool it, fans, etc, you need about 60a. This is more, way more, than most sheds are wired for. w/o that, your plan is dead from the get go. Find out how much service the shed has and take it from there. As for the growing, ur putting the cart before the horse. 50,60, 70 plants, that's a LOT of work and attention that has to be done in a timely, scheduled, organized manner. Starting with that many plants is just a bad idea. If you've done 5, I suggest trying 12 next.
Oh sorry ! Wasnt trying to offend ! but you have clearly no where near the experience to be jumping into a 5000 watt grow.. thats all... Maybe a smaller grow would be better for you... Your saying your budget is 250 $ ..... that MIGHT cover the cost of soil for 70 plants... You just have no idea what your talking about, or getting into, and youve proven it with every post. Good luck , your gonna need it , and you should be happy some high rep members are wasting their time even attempting to help you with this obviously flawed idea, and destined to fail plan. Good day sir.
If you don't have a fan and carbon filter already you are going to need it, and that alone is going to run you about 200. I HIGHLY suggest running 1 light to start with. This will give you experience running a 1000w light and help you bide time to get more money and equipment. This will also allow you to wait to start a bigger and hotter grow until cooler temps roll in. When you grow (not legally) SECURITY is your number 1 priority. And with growing odor control is # 1. If you do not have VERY secluded land (miles) you will absolutely need carbon filters. Get yourself a 400CFM inline fan and a carbon filter. Growing in a shed you will probably need at least 1 AC but if you are running only 1 light that should be fine. Additionally your shed may not have the wiring necessary to run more then 1 light, the fan and AC unit you will need. And don't try to jury rig your wiring if you don't know what you are doing, that is a good way to start a fire and a fire is a good way to have the authorities show up at your grow.