The weather is cooperating, and the plants in the landscape are starting to leaf out. You see some unusual leaf damage. Could it be slugs and snails? Yes, it could, but you have checked your plants in the evening (when they feed) and don’t find any critters, and besides the leaves don’t look like they are chewed. One other culprit might be that your soil is lacking nutrients; if you suspect this condition, get a soil testing kit at your local nursery.

During this time of year, it is common to have soil deficiencies, particularly with the abundance of rain we had this last winter. Fertilizers can be confusing, but nutrients are needed by active, growing plants. Many of these are present in the soil, water and air, but gardeners need to supply others. Most likely to need supplemental feeding are annual vegetables and flowers, lawns, perennials, and fruit trees.

First, read the fertilizer label. Most fertilizers contain macronutrients and micronutrients. All plants need these substances in fairly large quantities. Macronutrients include nitrogen (N), phosphorus (P) and potassium (K), and also secondary nutrients.

Nitrogen helps plants with proteins, chlorophyll, and enzymes. Nitrogen is the nutrient most likely to be lacking in garden soils. Too much can make plants too leafy (often at the expense of flowers and fruit) and prone to attack by sucking insects. Applied too late, it promotes new growth that’s vulnerable to frost damage.

Phosphorus promotes flowering and fruiting, strong root growth, and the transfer of energy within the plant. Phosphorus deficiency is rare, and an overdose can interfere with a plant’s absorption of other essential elements.

Potassium helps regulate the combination of proteins and starches that make sturdy plants. It also helps increase resistance to diseases, heat, and cold. Too much potassium interferes with the absorption of calcium and magnesium, making plants grow poorly.

Plants need secondary nutrients in about the same amounts as they do the macronutrients. But they’re less likely to be deficient in most soils. Calcium (Ca) plays a fundamental role in cell formation and growth, and most roots require some calcium right at the growing tips. Magnesium (Mg) forms the core of the chlorophyll found in the plant leaves and sulfur (S) acts with nitrogen in the manufacture of protoplasm for plant cells.

Micronutrients (also known as trace elements) are required in very small quantities. Among them are zinc (Zn) and manganese (Mn) — both thought to function together with other nutrients — and iron (Fe), essential for chlorophyll. Some plants, such as Swiss chard, need boron (B), an element often lacking in our alkaline soils.

When you go to the nursery to purchase fertilizer, there are many to choose from. Complete fertilizers contain nitrogen, phosphorus and potassium. Some may also include secondary nutrients or micronutrients. Simple fertilizers supply just one macronutrient; most familiar are the nitrogen-only types, called ammonium sulfate (21-0-0), and phosphorus-only super phosphate (0-20-0). Incomplete fertilizers fall between simple and complete; an example is 0-10-10, providing phosphorus and potassium but no nitrogen.

Special-purpose fertilizers are formulas designed to meet specific needs. High-nitrogen blends (such as 29-3-4) help keep lawns green and growing quickly. Higher-phosphorus mixes (6-10-4) for example are intended to promote flowering and fruiting. Other packaged fertilizers are formulated for particular types of plants. Those designed for acid lovers such as camellias and rhododendrons are especially useful, as are fertilizers for citrus.

I realize that fertilizers can be confusing, particularly when you are looking at 25 to 30 different fertilizer types at the nursery, and what I suggest, after you check your soil, is to take your soil readings to the nursery, along with the list of various types of plants you wish to fertilize. Talk with a nurseryman or -woman to make sure you are purchasing the correct fertilizer type.

If you have any gardening questions, text or call me at 17733833309.