Home Garden Tips & Techniques - Taking Quick Action

Many insect, disease or nutritional problems are much more easily cured or controlled when quick action is taken. If damage is observed too late, treatments may be of little help and production or beauty reduced or destroyed. Frequent observation is important to catch developing problems early. Try to take a daily quick walk through the garden to observe small changes. It will not only solve problems, but can take your mind off your own for a few minutes.

In observing nutritional growth problems, make first observations on the older leaves near the base of the plants. In many cases these will be the first to show disease symptoms or fertilizer deficiencies. The second most important area is near the youngest leaves at the tip of the plant. The young, rapidly growing areas are often first choice of insects, such as aphids, as well as minor element deficiencies and diseases.

A single symptom may have multiple causes. When checking trees and shrubs that have been in place for many years consider the past season's weather or environmental or cultural conditions when trying to determine exact causes of a problem. Poor growth with a sickly yellow color in many plants is an indication of minimal nitrogen. Root or stem damage that may interfere with its movement in the plant may create the symptom. On some plants, lower leaves dry up or drop off as the nitrogen in them is moved to younger leaves.

Too much nitrogen, on the other hand, may kill roots and result in similar leaf burn or stunted growth. In these cases the leaf burn will usually occur on the edges of the younger leaves. Low phosphorous results in plants that have poor growth with lower leaves that may develop a purplish color. Phosphorous deficiency is often most apparent in seedling plants. Potassium, or potash, deficiency often appears as a burn on leaf edges, starting with the lower leaves and working upward. In many crops the dead edges break off and leaves look ragged. Plants that are very deficient have poor growth and are often weak and may fall over.

Often, as seedlings grow in the garden, the phosphorous and potassium symptoms that may have existed become less severe or disappear without treatment while the nitrogen deficiency symptoms persist. If this happens it is because when the root system expands, roots are able to pick up phosphorous or potassium held in surrounding soil. The more extensive the root system becomes, the more they are able to absorb. Nitrate, on the other hand, moves freely in the soil and can be taken out of the root zone by the crop in a fairly short time.

Minor nutrients such as magnesium, iron or boron may also become deficient, but these are not normally a problem in the home garden. The dying of lower leaves that is characteristic of some fertilizer deficiencies may be confused with the dying of lower leaves in response to disease. While some deficiencies and other cultural problems may result in a scorch of leaf margins, diseases often develop with round or irregularly shaped spots of dead tissue in the leaves.

Some spots will be definite and stable while others will continue to spread and fuse together. Diseases that infect leaves while wet or in high humidity cause most damage to leaves low on the plant. They may then gradually spread upward. The causes of plant problems are many and often complex.

American Horticultural Society Pests and Diseases by Pippa Greenwood.