EDDIE SEAGLE: Keep your plants healthy and colorful

“The world’s favorite season is the spring. All things seem possible in May.”

— Edwin Way Teale.

May is here and the weather is awesome. Flowers are blooming and the pollen is all around. So, let’s look at some basic plant needs to keep them more healthy and colorful.

Plants need water and nutrients for survival. Most plants need about an inch of water per week on the average to accommodate their metabolic and systematic needs. However, it appears that in the last few years, we either experience a very rainy season or a very dry season or any combination. As we receive higher rates of precipitation, we have to become more aware of leaching (removal of nutrients with percolation through the soil profile) which robs the plant of necessary nutrients. Therefore, fertilizers enter the picture and must be addressed.

Understanding nutrients and fertilizers is most critical in managing the needs of plants in your home landscape. Before any fertilizer application takes place, it is important to soil test to determine the exact nutrient composition of your soil micro environment. Randomly collect about one to two cups of soil from each zone within your landscape from the lawn to the flower areas to the special plants (roses, azaleas, etc.) to the trees and shrubs. Keep these samples labeled separately and place in a plastic bag which you will then place in a basic soil testing bag available from your county agent office. Have these tested through this public agency for a nominal fee and allow time for the testing results to return to you. From these results, a determination can be made on the needs in each micro environment. Soil tests should be conducted every one to two years in the home landscape.

An easy statement to remember the nutrients is C HOPKINS CaFe Managed By Mine Close CuZn Mo (anonymous). From this statement you should recognize carbon (C), hydrogen (H), oxygen (O), phosphorus (P), potassium (K), iodine (I), nitrogen (N), sulfur (S), calcium (Ca), iron (Fe), magnesium (Mg), boron (B), manganese (Mn), chlorine (Cl), copper (Cu), zinc (Zn), and molybdenum (Mo).

Carbon, hydrogen and oxygen are readily available and do not need to be supplemented. The macro nutrients are the major nutrients (nitrogen, phosphorus and potassium) needed in the largest amounts and the minor nutrients (calcium, magnesium and sulfur) needed in medium amounts, usually expressed in pounds per acre, per thousand square feet or per 100 square feet.

The micro nutrients are iron, manganese, boron, zinc, chlorine, copper, zinc, iodine, and molybdenum. Other micro nutrients are needed but are usually present in sufficient amounts. Iron is needed in the largest amounts and is expressed in ounces per acre, per thousand square feet, or per hundred square feet. The others are needed in grams per area or in parts per million (ppm).

Nitrogen is not part of a soil test because of its mobility in the soil and volatilization characteristics. If necessary, tissue tests can be conducted to determine nitrogen levels, otherwise follow recommendations for subject plants. A soil test should be conducted for pH, P, K, Ca, Mg, Fe and other micro nutrients. The pH (potential hydrogen) identifies the degree of alkalinity or acidity of the soil. The pH range is from 0 to 16 with 7 being neutral (below 7 is acid and above 7 is alkaline). Most plants in the area grow between pH of 6.0-7.0, excepting acid-loving plants like centipede grass, azaleas, etc, which prefer 4.5 to 5.5.

If your pH needs adjusting, add lime to increase and sulfur to lower. By maintaining your pH between 6.0 and 7.0 for most plants, calcium and magnesium will be readily available. As pH changes, so does the availability of nutrients. The soil test results will indicate what you need to do with pH.

The soil test results will further indicate the amounts of these nutrients present, and these will be either deficiencies, optimum levels, or toxicities. With the cost of fertilizer and plant health at a premium, you only want to apply what is needed. Ask the testing unit for a recommendation for your particular plants for each sample tested. If you haven’t soil tested, now is a good time to do it. If you soil test regularly, then late summer or early fall would be ideal. If your soil pH needs adjusting (which takes a few months to achieve) you will certainly have time to make the adjustment before spring and new growth.

Complete fertilizers are those that contain amounts of nitrogen, phosphorus and potassium (N, P, and K). These fertilizers may also contain one or more micro nutrients (see label on fertilizer bag), as well as an herbicide to kill weeds (a weed and feed formulation). An incomplete fertilizer does not contain all three nutrients (N, P, and K) and may be labeled as nitrogen, phosphorus, potash, or iron fertilizers, as well as sulfur fertilizers and general micro nutrient fertilizers. Most of the formulations that may be needed are readily available at your local garden center.

Fertilizer formulations contain active ingredients (the nutrients) and inert ingredients (the filler or the carrier). The analysis is the concentration of nutrient(s) in the bag. For example, in a 16-4-8 fertilizer analysis (16%N, 4%P and 8%K), the percent active ingredient is 28% (16 + 4 + 8) with 72% (100% – 28%) as inert materials. Most fertilizer formulations to the consumer are packaged in 40 pound bags or less (rose fertilizers may be found in 5 pound bags).

Understanding fertilizers is most critical from purchase through handling to application. Only purchase the amounts needed with little to no leftover. Read the label carefully and understand what it indicates to you. Seek advice at all times. Use the right equipment to make your fertilizer applications to achieve correct rates and uniformity in application. Each fertilizer application should be watered-in successfully with approximately 0.5 inches water. Whether you are fertilizing a large area (lawn or flower bed) or an individual plant, be sure to follow recommendations closely and carefully.

Realize that specialty fertilizers exist for special plants like centipede grass, roses, azaleas, camellias, annuals, perennials, trees and shrubs, lawns, etc. You should make every effort to use these specialty fertilizers on your specific, specialty plants since you will get the best results offering the highest degree of safety to the plant.

This short lesson in nutrients and fertilizers is only a sample of the knowledge to be learned about managing the nutrition in your plants. May this small degree of awareness ignite your desire to learn more and ask questions, encourage you to further apply your gained knowledge, and bring you to further realize that environmental stewardship and sustainability are at the foundation of all your home landscape activities.

So, just get outside enjoy your spring gardening! And remember to feed and water the songbirds, and give your pets the care they need (do not leave them unattended in a hot car or tied to a tree all day long).

“Praise the LORD, O my soul, and forget not all His benefits — who forgives all our sins and heals all our diseases…” Psalm 103:2-3.

Eddie Seagle is a sustainability associate, Golf Environment Organization (Scotland); agronomist and horticulturalist, CSI: Seagle (Consulting Services International); professor emeritus and honorary alumnus, Abraham Baldwin Agricultural College, and associate editor of The Golf Course, International Journal of Golf Science. Direct inquiries to [email protected].