Nutrients must supply your plants with everything they need - apart from light and water - so it pays to choose the best! That's why we spend a lot of time researching and testing nutrients for you! Nutrients divide into 'Grow' and 'Bloom' formulations, and often into 'Hard' and 'Soft' versions to suit your tap water. Make sure you know which option is right for your area before you buy. If your kettle collects a white furry deposits then you have hard water and will require Hard Water (HW) nutrients. If you are unsure then choose soft water nutrients.