MARY JO R GIBSON
formed into a small pellet designed for use with a spinner-type spreader. Use a drop-type spreader to apply pulverized lime. Both work equally well. Lime can severely hinder plants like blueberry, azalea, and rhododendron, which prefer a low pH. These plants often benefit from a light application of sulfur. How do you know if you should apply sulfur to your acid-loving plants? Invest in a separate soil test for each specialized area. When the soil pH is correct, essential nutrients will be available to plants if they are present in
pH levels also reduce the availability of calcium and phosphorus. Minor elements are seldom lacking in soil. Most minor elements are already present. Organic matter and commercial fertilizers are good sources. Some minor elements are toxic to plants when applied in excess. Fertilizer comes in two basic forms: organic, often called natural, and inorganic, often called chemical or synthetic. Organic materials originate from living organisms. Bacteria break them down in the soil into inorganic, water-soluble forms. Inorganic materials are mineral salts that are
the soil. How do you know if nutrients are present in the correct proportions? The soil fertility test report, of course! Organic matter is the most effective material for improving the soil. Compost and other plant residues increase soil
"Organic matter is the most effective material for improving the soil"
already water-soluble. When a nutrient is in an inorganic form, it is helpful to the plant, whether it originated from organic matter or inorganic fertilizer. Natural organic fertilizer includes all animal manure and
SOIL p H & FERTILIZER Penn State Extension Master Gardener of Columbia County Mary Jo R. Gibson, Dirt is what we vacuum from our carpets and
water-holding capacity and provide pore space when incorporated into the soil. Organic matter prevents tiny clay particles from cementing themselves into a solid mass. It increases the cation exchange capacity or C.E.C. The C.E.C. is a measurement of a soil’s ability to hold nutrients. Organic matter also promotes the growth of microorganisms to condition the soil.
compost. Commercial organic fertilizers include dried manures, feather, bone, and blood meals, and cottonseed and soybean meals. The nutrients become available over a longer period and are less likely to be leached from the soil. Organic fertilizers generally cost more than inorganic types and are unavailable to plants until soil microbes break them down. What do those numbers on a bag of fertilizer represent? By law, the label on the fertilizer package must indicate the amount of nitrogen (N), phosphorus (P), and potassium (K) in the product in that order. Each number equals the percentage of the element in the bag. A bag of 5-10-5 contains 5% nitrogen, 10% phosphorus, and 5% potassium. The rest of the bag is filler. Before you think such low percentages are wasteful, remember that concentrated nutrients will damage the plants we want to nourish. Fertilizer formulations suitable for general garden use are 5-10-10 and 5-10-5. For the most part, fertilizers with a 1:2:2 or 1:2:1 nutrient ratio of N, P, and K will meet your needs. For planting vegetable and flower transplants, you may wish to use a high- ratio, water-soluble fertilizer, such as 10-55-10 (1:5:1). Test every three to five years to make the best use of your soil. Apply lime and fertilizer only as indicated by the soil test report. Over-fertilization is more serious than under-fertilization. Remember: More is not better. Soil test, don’t guess! ❚
After you receive the soil fertility report, apply the nutrients recommended in the soil test so your plants will thrive. Applying more soil nutrients than recommended is detrimental to your plants, reduces crop quality, harms the environment, and wastes your money.
wash off our cars. A gardener distinguishes dirt from the soil, that wonderful earth where we grow our plants. So, what is soil? Soil anchors plant roots and serves as a nutrient storehouse. Minerals, air, water, dead organic matter, and living organisms make up soil. The mineral portion consists of tiny fragments of weathered rock, such as sand, silt, and clay. The percentage of each determines the soil’s texture. The amount of water and air that soil can contain depends on its texture and structure. The more intensive the gardening, especially in vegetable plots or flower beds, the more critical it is to understand the soil. The information from a soil fertility test is valuable before the ground is planted for the first time. Making changes in soil quality is more challenging once you’ve planted a landscape. Testing soil fertility every three to five years is usually sufficient. Sampling in early spring or late fall ensures you will have soil test results and recommendations before buying lime and fertilizer. Late-fall sampling will allow you to adjust soil pH in time for next year’s crop. You can obtain Penn State Agricultural Analytical Services Laboratory soil fertility test kits from your local Penn State Extension office. There is a $10.00 fee for the analysis and fertilizer recommendations. The kit contains an information sheet for each soil sample, which the lab needs to make lime and fertilizer recommendations. Receive soil test results and recommendations in about ten days.
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It is essential to apply the correct amount of lime. Most plants do well when the soil pH is between 6.2 and 6.8. The pH is a measure of a material’s alkalinity. The pH range is 0 (extremely acidic) to 14 (extremely alkaline), with 7 being neutral. When acidic soil is neutralized by liming, soil nutrients become more available for plants to absorb through their roots. Usually, when we see a micronutrient deficiency in a plant, it is because the soil’s pH has limited the availability of that nutrient. In addition to raising the soil pH, lime also supplies calcium and magnesium to the soil. Calcium is critical to avoid blossom end rot on tomatoes. Tree fruits are sensitive to shortages of calcium. Lime is the most inexpensive way to supply these nutrients. Lime is classified as high calcium (calcitic) or high magnesium (dolomitic) lime. High calcium lime contains 3% or less magnesium. Which type of lime do you need? Read your soil test results. Pelletized lime is pulverized lime, moistened, and
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Add organic matter such as manure, compost, peat moss, humus, or mushroom compost to the soil. Some organic matter, especially manure, is relatively high in nitrogen, phosphorus, and potassium. Use only enough to meet your plants’ needs. Excessive soil fertility is a problem. Extra nutrients can reduce the quality and yield of produce and wash away. Pollution causes harmful effects on fish and other aquatic animals. Remember that soil pH directly affects the availability of plant nutrients. Calcium, magnesium, manganese, copper, zinc, iron, and boron are most available to plants when the soil pH is 6.0 to 6.8. Low
Mary Jo R. Gibson has been a Penn State Extension Master Gardener of Columbia County since 2003.
COLUMBIA MONTOUR Quarterly
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April–June • 2026
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