Xtremehorticulture

Am I Applying Too Much Nitrogen?

Q.
We fertilize all of our bushes early spring and mid fall with a 5-10-5 liquid
plant tonic.  Hopefully this isn’t too much
nitrogen.

This concentrated fertilizer
 has no nitrogen but very
high percentages of phosphorus
and potassium
A.
There are two ways to look at this question. Applying too much nitrogen can
mean either applying it too often or applying too much in a single application.
If you follow label directions, the amount of nitrogen applied should be
correct. Apply nitrogen as often as 8 weeks apart if you want continuous growth.
             Applying excessive amounts of nitrogen can damage plants or cause excessive growth of leaves and stems.
            When judging how much fertilizer to
apply and how often, observe the plant. If the plant does not have good growth
or the flower size and numbers have diminished, apply fertilizers or “plant
tonics” if you prefer.
Applying too much nitrogen, the first
number, is not normally a long-term problem. The potential long-term problem involves the over application of the second or
middle number, phosphorus. 
Phosphorus stays bound in many soils for much longer
periods of time than nitrogen. Apply fertilizers containing high levels of
phosphorus (middle number) less often than fertilizers that contain high levels
of nitrogen.
As a general rule of thumb, apply
fertilizers containing phosphorus once a year
to established plants, two weeks
before flowering. The rest of the time use high nitrogen fertilizers.
The exception is at planting time. Every
time seed or transplants go in the ground, apply a high phosphorus fertilizer.
Before planting, mix high phosphorus fertilizers in the soil to the same depth
the roots will grow.
Bagged compost can be hard to find. Most
bagged products that contain compost are
soil mixes, not straight compost.
Consider using compost instead of a
mineral fertilizer. I am talking about compost which is harder to find, not a
soil mix that contains compost. Most composts have a good balance of nitrogen,
phosphorus and potassium and can be used as a substitute for mineral
fertilizers.

Composts provide plants with a lot of
minor elements not found in mineral fertilizers. Compost lowers soil
alkalinity, stimulates good soil microorganisms and provides humus or “black
gold” to the soil. It is a very powerful addition to desert soils.

Leave a Comment

Your email address will not be published. Required fields are marked *