the growth or ‘vegetative’ phase, plants have a particularly high demand
for nitrogen. Consequently, “grow” nutrients contain a relatively high
concentration of nitrogen to help ensure plants do not run out of nitrogen
the bloom phase, the demand for phosphorus and potassium increases.
Consequently, “bloom” nutrients
contain a relatively high concentration of both phosphorus and potassium,
but relatively low nitrogen. Hence, switching to “bloom” during the
flowering phase will help ensure plants do not become deficient in
potassium and phosphorus. This is especially important for heavy fruiting
plants such as tomatoes and strawberries.
The use of grow and bloom nutrients at the appropriate times is also more
economical. For example, the use of bloom during the growth phase would
result in the excess phosphorus and potassium being wasted. This wasted
nutrient potentially becomes an environmental concern when the nutrient is
discarded – particularly in large commercial operations.