If your growing in soil,wallmart carry's an aquarium ph test kit that mesures a ph between 6 and 7.5 and it comes with ph down and up cost under 20 bucks.A bit of advise test the first drops of water that come out the bottom of your container as you water to know the ph of your soil so you can ad the corect ph'd water as the soil can get low ph,you may have to water with a ph of 7.5 or lower,or you can add something to your soil as i have added wood ash and only water with tap water ph of 6.8 after it's been sitting 24 hours o and don't let it sit on cement floor.Even a swimming pool ph kit would work