Several days ago, one of my favorite comic strips depicted the rather well rounded mother explaining to the petite daughter that as we age we add pounds. I'd like to agree, but the way my doctor pounces on each new pound, tells me that I shouldn't use the words fat and happy in the same sentence. Maybe fat and happy might work in the garden. In the plant world there are two schools of thought. One suggests that a well-fed plant has the strength to fight off insects and diseases. The other suggests that well-fed plants with lush growth are just a magnet for insects and diseases.

When examining a fertilizer label you will see three numbers. A common example might be 20 10 10. In order, they define the percentages of nitrogen (20%), phosphorus (10%) and potassium (10%) in that fertilizer.

Briefly, and at the risk of over simplification, nitrogen promotes growth, phosphorus produces flowers and fruits and potassium feeds the roots.

Now let's step back several paragraphs and tackle the relationship between fertilizer and insects. The University of Illinois recently released a detailed study involving varying rates of nitrogen and the presence of mealy bugs on green and red coleus.

First, I must note that a very low level of nitrogen showed slightly less insects than the no fertilizer control. That rate was about one eighth of what is commonly used in large commercial greenhouse production and one fourth what I use.

The trial tested double, four times, eight times and 16 times the low rate. In each case as the fertilizer rate increased, the number of insects as well as the number of insect eggs increased. Even more alarming was that the time for an insect to grow and reproduce shortened as the rates of nitrogen increased.

Other, less detailed research suggests that other sucking insects like aphids and white flies would follow the same pattern.

One interesting side note was that the insect population in each case was higher on the green coleus than it was on the red one. I can easily believe that. From my experience there are often differences between cultivars of a given plant.

At this stage of the season the fertilizer should be all used up or in the garage. The only exception might be a root building application to the lawn. That one would have a large third number and two very small numbers in front.

I know our urges. Fat and happy is so much easier. A little restraint would help both our plants and us.