Nigel's Gardening Hints And Tips
Created | Updated Jul 13, 2009
Plant Nutrients
Plants need a whole range of different things to grow but why do they
need nutrients? Well, just like us, plants need nutrients to survive
and do their best.
Now, I don't mean feed them fish and chips! The nutrients plants need
are different to us and there are specialized fertilisers on the
market to help.
I will now talk through the essential nutrients plants need:
The first one is nitrogen. N, short for nitrogen, is essential for
growth of the stem and leaves. If a plant is short of this, the leaves
will turn a pale yellowish colour and usually drop off. The plant will
stop growing and eventually cause it to die. The older leaves will be
affected first as the nitrogen will automatically be used up by the
younger parts of the plant. You usually find nitrogen deficiency in
very wet and cold soils and also very well drained soils, as the rain
or water washes the nutrients away before having time to be absorbed
by the plant.
However, you can have too much nitrogen which will cause a potassium
deficiency; we will cover that nutrient later on.
The second major nutrient is called P, short for phosphorus. This is
important in germination of seeds, the quality of the flowers and
fruit and the root growth. When there is a phosphorus deficiency, the
plant lacks growth and produces very small leaves which drop off as
quick as they came on. Leaves are a dull colour with a bluish green
tint to begin with, then a purplish, bronzy colour with leaf edges
being a scorched crispy brown colour. As with nitrogen, there is such
a thing as too much phosphorus which causes a potassium deficiency.
The third major nutrient is called K, short for potassium in
scientific terms. This nutrient prevents the plant from picking up a
virus or disease. It helps keep the plant healthy and grow to its best
capacity. If a plant is short of this, it will lose vigour and health,
and won't grow, having stunted growth. The leaf edges will roll and
cause them to be brown and crispy with a scorched look. If a plant has
too much Potassium then it could cause calcium and magnesium
deficiencies.
The fourth major nutrient is Ca, short for calcium. A calcium
deficiency will cause the plants teeth to deteriorate - oh, sorry,
reading the wrong books! Seriously, calcium is a major ingredient in
the production of cells needed for healthy root growth. It helps
produce good root growth and healthy tips needed to keep the plant
stable and upright, protecting it from the harsh weather. You
sometimes see plants or trees that have collapsed, normally these
would of been suffering from a calcium deficiency, the chance of them
coming back from this stage is very slim. You usually find with a
calcium problem that the leaves of the plant will have hooked tips and
curled margins, which very often turn a brownish colour. The plant
will seem loose in the pot and on the brink of collapse.
The almost last major nutrient is Mg, short for magnesium. This is
important to the chlorophyll production (greenness of the leaves) and
will cause the leaves to yellow without showing any signs of wilting,
suddenly dropping off usually with the older leaves first. Leaves may
have a brilliant yellowish tint but is difficult to say exactly
because it varies from plant to plant. Excess magnesium can cause a
calcium deficiency.
The last major nutrient is S, short for sulphur. Sulphur is rich in
proteins and, just like magnesium, is important for chlorophyll
production. Unlike the magnesium deficiency, sulphur deficiency causes
the plant to grow very very slowly, almost stopping altogether.
Sulphur deficiency causes the leaves to roll upwards and are very
stiff and brittle. The tips of buds die and drop off causing the plant
to lose it vigour and shape.
So, those are the major nutrients a plant needs in order for it to
grow and flourish. If you suspect plants in your garden have a
shortage of one or more of these nutrients and you are not sure which
deficiency they are short of, then a soil test kit available from
garden centres will give you an accurate and complete diagnosis of
what the soil is lacking.
If there is a sick plant in a pot which is lacking a major nutrient,
then the best thing to do is either re-pot it or feed it with a
general based fertiliser which has an equal amount of nutrients in it.
Usually, the best fertiliser to buy is an organic based one as it
usually lasts longer, releasing the nutrients more slowly than normal
ones.
Shallow rooted plants such as grass, and some alpines need more
phosphorus and potassium as the roots do not extend deeply enough to
gather these potentially important nutrients.
If you find you perform the soil test or know by my plant diagnosis
which nutrient/s your plants are suffering from, then garden centres
offer a good range of specific fertilisers for shortage of these
potential nutrients. If your plants are suffering from different
nutrient deficiencies, then it will be best to buy a multi-purpose
fertiliser with all the potential nutrients in needed to correct and
help the deficiency of your plants.
Make sure that you follow all instructions carefully on the box and to
repeat the feed after the first application, as specified on the
instructions.
Have fun.
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