Masterblend 4-18-38 Hydroponic Fertilizer (2 lbs) Free Shipping MasterBlend fertilizer can be used for hydroponics and soil gardens. I have re-packaged it in a heavy plastic zip-lock bag. It is a brand new Masterblend fertilizer that is repackaged into a smaller, more convenient size. Masterblend can be used for hydroponics, aeroponics, and plants in soil. I am positive you will love using Masterblend. I will also include mixing instructions for greens like lettuce and nutrient hogs like tomatoes so you can ensure you are mixing the right ratio to feed your plants properly. It is the only fertilizer that I use on my tomato and vegetable plants.