Does the “balance” of nutrients matter or just quantity? (ASK Advice)

Balancing means looking for the Goldilocks zone -- not too much, not too little, but *just* right! When it comes to soil chemistry and nutrient levels, more isn't always better. Here are three aspects of soil health where we need to focus on maintaining balance rather than increasing quantity.

1) pH. Most plants thrive in soil that is near neutral pH, with some exceptions (such as blueberries prefering slightly acidic soil). Very high (alkaline) pH and very low (acidic) pH can decrease the ability of plant roots to absorb nutrients from the soil. You can browse our website to find more articles about balancing soil pH.

2) Nutrient levels. Some essential plant nutrients can actually be toxic if present in high quantities! This is analagous to needing water to live but drowning in too much water. Iron, manganese, copper, boron, and chlorine are examples of essential plant nutrients that are potentially toxic in excess. This is one reason it's important to get your soil tested before applying fertilizers and to stay within the recommended application levels.

3) Cation nutrient ratios. This is the most complex topic related to balancing soil chemistry. When there is an excessive amount of one nutrient in the soil relative to the others, it can actually block plant roots from taking up the less plentiful nutrients in some cases. This can happen even if all individual nutrients show up within a healthy range on your soil test. As a common example, over-abundant levels of soil calcium can lead to plants with a potassium deficiency, even if the potassium levels aren't considered low. In order to check for this issue, you'll notice that your soil test report includes both the amount of each nutrient present in the soil and the base saturation percentage for each cation compared to the total cation exchange capacity. Soil cations include calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), and acidity, which is reported in terms of hydrogen (H) ions. There are different opinions about what the "ideal" balance of soil cation nutrients is, depending on soil type and what plants are being grown, but the classic rule of thumb is 65% Ca, 10% Mg, and 5% K (although a wide range is acceptable).

For all three of these topics, one of the best things you can do to keep your soil balanced is to maintain your organic matter content, since organic matter acts as a buffer or sponge that soaks up nutrients and acidity when there's too much and releases them when there's too little. And as always, yearly soil testing so you know what ammendments your soil needs and which ones it doesn't!