Definition - What does Nutrient Stagnation mean?
In hydroponics, nutrient stagnation describes a situation in an indoor growing application where a water/nutrient mix, known as a nutrient solution, sits for too long without being taken up by plant roots. It can stagnate (ceases movement), and mold and mildew can begin to proliferate. Nutrient stagnation is a particular concern when the nutrient solution is not chilled.
A stagnate nutrient solution becomes stale, and in addition to mold, mildew, or algae growth, the pH of the solution can also be effected. In addition, certain types of nutrients don't mix well, and only should be mixed upon delivery to plants. If left to stagnate, such nutrient salts can essentially become too big or too much for uptake via the plant roots, leading to nutrient lockout.
MaximumYield explains Nutrient Stagnation
Indoor growing, particularly hydroponics, can be incredibly beneficial, but it comes with many potential pitfalls. One of those is the fact that the nutrient solution in which plants are grown must be kept in motion. Failure to do so can result in nutrient stagnation.
In this situation, the nutrient mix does not move adequately, and stagnation begins to occur. Mold and mildew can quickly enter the system and proliferate, eventually causing serious damage to plant roots, and even plant death in some instances.
Preventing nutrient stagnation requires that growers do several things. First and foremost, a means to keep the nutrient solution in motion is needed. This can be as simple as manually stirring the solution a few times per day, or as complex as installing a recirculating pump to keep the solution moving. Nutrient dosers can also be installed. These devices automate the release of the nutrients, ensuring they aren't sitting in solution for long periods before being taken up by plants.
Another consideration is the frequency with which the nutrient solution is drained and refreshed. Even if kept in constant motion, the solution will eventually stagnate and cause problems for plants. The nutrient mix will need to be changed regularly, although the specific time frame will vary depending on factors such as the size of your growing area/volume of nutrient mix, number of plants being grown, and more.
Note that nutrient stagnation can affect all indoor growing applications, including hydroponics, aquaponics, and others.