The Online Gardener's Handbook
Chapter 3: A Word about Soil
Table of Contents
- Major Nutrients and Micronutrients
- Learn More
Plants take up their water and nutrients from the soil. For healthy
plant growth, therefore, the soil must be adequately supplied with
both. A number of nutrients are essential for plant growth, and
plants take up these various elements at different rates depending
on the stage of growth.
In the spring and summer, when plants are in a vegetative stage,
great levels of nitrogen and phosphorus are required. At flowering
and fruiting, higher levels of potassium and calcium are needed,
and very little nitrogen is absorbed. Perennial plants as well as
trees, shrubs and grass will absorb a high amount of nitrogen from
the soil and store it both in the roots and crown. This will be
used for mobilization in the spring when the rate of growth is very
Major Nutrients and Micronutrients
Nutrients fall into two categories depending on the
amount used by the plant. Major plant nutrients are nitrogen, phosphorus,
potassium, calcium, magnesium and sulphur. Of these, nitrogen, phosphorus
and potassium are most likely to be deficient in lawn and garden
soils. Calcium and magnesium deficiencies are rarely seen except
in low pH or sandy soils.
Micronutrients, although required in small quantities,
are equally important and essential to plant growth and development.
These nutrients include zinc, manganese, iron, copper and boron.
Generally, they are not deficient in lawn and garden soils. Depending
on the plant species, micronutrient deficiencies may occur in sandy
soils, in back-filled areas, or when soils are too alkaline.
Lime-induced iron chlorosis is the most common micronutrient
deficiency problem in home gardens, especially with azaleas, rhododendrons,
blueberries, Hydrangea macrophylla, and pin oak. Leaves yellow,
though the veins remain green; as the problem worsens, leaf tissue
becomes almost white, with burning around the edges.