Always check the dosage on your label before application. The coffee and vinegar methods would be ok in small potted areas but not really realistic for large areas. I will try the vinegar first and give it a week or so. But there are other plants, such as flowers like azalea, marigolds or heather and fruits and vegetables such as blueberries. Last update on 2020-11-30 / Affiliate links / Images from Amazon Product Advertising API, The Best Strains for Greenhouse to Get the Most Out of Your Grow, Tony Jr is the Founder and Editor-in-Chief of THCoverdose.com. But it’s better than just guessing. B.C. And if you’re overusing them to make up for the pH levels not being right you might as well throw money down the drain. Please respect the marijuana laws in your state. It may take more than 10 pounds of iron sulfate per 100 square feet of soil to reduce the pH level by one; if you do need to add more than that, it’s best to split the quantity into two applications that are spaced a month or two apart. When trying to determine the pH based on a color chart, a lot of it is left to speculation. If you are primarily a hydroponic grower, be sure to check out our guide here. Remember, nutrients cost money. Nothing on this website should be considered legal advice. In which case I would choose Iron Sulphate as my first choice (this will help to reduce aluminium toxicity in the soil) and if i couldn’t get that then my second choice would be Aluminium Sulphate. Black Magic PH DOWN is used, after initialing testing the PH of your plant, to lower the PH if required to ensure the plant is absorbing the maximum nutrition. They need between pH 5.8-6.5. If you would like more information about soil, its profiles and horizons, take a look at my article “How Soil is Created” for more info. If you want to test the pH of your soil, there are other ways to do it besides a soil pH meter. pH DOWN™. They need pH 5.0-5.5. pH varies from spot to spot, so this gives you a better representation. By far the most accurate meter ranging with +/- .1 pH accuracy. Reading #1 + Reading #2 + Reading #3 = Total ÷ 3 = pH. And although soil pH varies from region to region and one garden to the next, most plants need a pH between 6.5 and 7. To lower the pH in larger areas i would use elemental sulphur if i wasn’t in a rush- but usually you do want the benefit within that growing season. If you’re growing hydroponically, you need a digital meter. I created GrowerExperts as a go-to resource for gardening enthusiasts around the world.