To grow crops successfully, you need to have good soil. Some people are fortunate enough to live in an area in which the soil is rich with nutrients and perfect for growing vegetables. For the rest of us, there are many ways to recognize a nutrient deficiency or an inappropriate pH and easy ways to fix these issues. You can always take a sample of your soil for detailed testing. Many universities and commercial businesses will test your soil for grain size, moisture, compaction, permeability, nutrients, pH, and more, but this is not always necessary. You may be able to make a few simple observations to determine your soil’s needs. Based on the deficiency, you can then add the correct supplement and turn your garden into a major producer at harvest time.
If you do go for an official test of your soil’s nutrient levels, the testing company or university will look for amounts of the three major nutrients: nitrogen, phosphorus, and potassium. They will also check levels of secondary elements like sulfur, magnesium, and calcium and minor nutrients like copper, iron, manganese, boron, zinc, and molybdenum. Spotting deficiencies of most of these elements on your own is not too difficult. If you suspect your soil is not perfect, you will also want to determine the pH and adjust accordingly with additives.
- Nitrogen. Nitrogen is one of the most important elements for plant growth. It is needed for the production of chlorophyll, genetic materials in the plants’ cells, and allows plants to grow the green leafy parts. If your soil is lacking in nitrogen content, your plants will turn pale green and eventually yellow, as inadequate chlorophyll is being produced. The yellowing starts at the bottom of the plant and works its way up to the top. It will also begin in older leaves first. You will also notice minimal new growth on your plants. To add more nitrogen to your soil, use alfalfa, guano, fishmeal, or cottonseed. Manures and compost will also work. Seaweed in the soil will encourage the growth of nitrogen-fixing bacteria.
- Phosphorus. Also very important to the genetic molecules DNA and RNA, phosphorus is essential to plant growth. It stimulates the growth of roots, flowers, and fruits and helps plants to resist disease. Plants with inadequate phosphorus will have dark green leaves with tinges of purple, especially on the undersides. The foliage may seem sparse, and flowers may not form or only a few will grow. In the short term, correct this deficiency by spraying the affected plants with a fish emulsion. Put wood ashes in the soil and use rock phosphate for a longer-term fix.
- Potassium. The third major element for plants, potassium helps water, nutrients, and sugars move through a plant. It also helps increase early growth and disease resistance and is a part of protein building, photosynthesis, and the production of quality fruits. With insufficient potassium in the soil, your plants will look dry and scorched around the edges of the leaves. Older leaves will be mottled with dead spots. The stems and root systems will be weak. The fruit will ripen in an uneven way. As with phosphorus, you can spray fish emulsion on your plants for a quick fix. To improve your soil in the long term, use granite dust, seaweed, manure, or hardwood ashes.
- Magnesium. Magnesium is essential for photosynthesis to occur. It helps plants use nitrogen and phosphorus and cleanses them of toxins. Signs of magnesium deficiency will show up first in the lower leaves. The veins will turn yellow, then orange, and finally brown. The leaves will be brittle and thin and form a cup shape. To add magnesium, mix one or two teaspoons of Epsom salts in a gallon of water and use this to water the plants. Do this three times over six weeks. You may also try adding fishmeal, greensand, or dolomitic limestone to the soil.
- Calcium. Calcium encourages early growth in plants and helps root hairs to form. It also increases soil pH. A lack of calcium will show up in new growth on plants. New leaves will be small and misshapen with black, curled tips. Root growth will be stunted. Use lime or add eggshells to your compost to increase calcium levels.
- Sulfur. An important component of the protoplasm in plant cells, sulfur is also responsible for the oils that create certain smells in garlic, mustard, and onions. It also helps produce oil in other less stinky plants. Sulfur deficiency looks a lot like nitrogen deficiency in your plants. A key difference is that the yellowing of leaves will start in young leaves when a plant is not getting enough sulfur. Stems will also be weakened by a lack of sulfur. To correct this problem, you can add sulfur or potassium sulfate to the soil. However, it is easy to use too much and cause sulfur toxicity. To correct sulfur issues, it is best to get a test and find out exactly how much you need to add to the soil.
- Boron. Boron is necessary for various mechanisms in plants including cell division, movement of sugar, and flower formation. When boron is lacking in the soil, stems will develop rust-colored cracks. Corky spots will pop up on fruits or their centers can be rotted. Leaves will get leathery and thick, and flowers may not form or bloom. New shoot tips get a “witch’s broom” effect. To increase boron in the soil, mix one tablespoon of borax to about 12 quarts of water. Apply it to plants twice over two or three weeks.
- Iron. Iron assists with the formation of chlorophyll and oxidizes sugars to produce energy. It is also used in legumes to fix nitrogen. Without enough iron, leaves on plants will turn yellow except for the veins. The discoloration begins at the top of the plant and works its way down. Shoots can possibly die back and fruits can be discolored when iron content is inadequate. To correct iron levels, first ensure that your soil is not too alkaline. You can also add bone or blood meal to the soil.
- Copper. Copper stimulates the growth of stems, helps pigments form, is a part of photosynthesis, and acts as a catalyst in respiration. With copper-deficient soil, plants’ leaves will begin to yellow in the center. The veins and edges will remain green for some time. Young leaves will fail to develop, and the tips of new shoots will die without copper. To increase copper in your soil, find an organic copper fertilizer.
- Manganese. Manganese is needed for the production of chlorophyll. When manganese is lacking, the symptoms will closely resemble those of iron and nitrogen deficiencies. The main difference will be that manganese-deficient plants will develop gray spots that resemble the kinds of spots caused by air pollution. Correcting manganese deficiency can be as easy as correcting the pH. If your soil has a pH that is too alkaline, bring it down to 6.5 or lower.
- Molybdenum. Molybdenum helps plants use nitrogen and stimulates the growth of plants through the production of proteins. Symptoms of a lack of molybdenum include yellowing and abnormally large older leaves. You may also see curling at the edges of leaves and unusually small young leaves. Inadequate molybdenum is mainly an issue with the brassica family in acidic soil. To correct a molybdenum deficiency, mix lime into the soil.
- Zinc. Zinc is responsible for the formation of flower buds and the growth of stems. It also plays a role in the synthesis of proteins. Without zinc in the soil, you will see similarities to iron deficiency. You will also see rolled edges on leaves and closely spaced leaves that are misshapen. An inappropriate pH may be keeping your plants from absorbing zinc. Your soil should be between 5.8 and 6.2 to have adequate uptake of zinc.
Identifying and Correcting pH
Having soil that is too acidic or too basic can cause your plants to fail to absorb certain nutrients. The best way to get an accurate read on your soil’s pH is to use a testing kit, which is easy to find. If you don’t need an accurate measure, there are some easy ways to tell if your soil is acidic or basic. Add vinegar to a sample of your soil. If it fizzes, you have basic or alkaline soil. Add a mix of water and baking soda to a fresh sample. If it fizzes, you have acidic soil. If nothing happens in either test, your soil is roughly neutral. To make soil more basic, add lime or wood ash. If it is basic, add pine needles or sulfur.
©2012 Off the Grid News