A plant must be actively growing for fertilizer to be of any use. Fertilizers are not food. Plants make their own food through photosynthesis. If you think plants are eating something, you’re right, it’s called sunlight. To be healthy, plants require sixteen nutrients, and once a plant is deprived of any of them, the plant will become sick and die. This rarely happens because most of these nutrients are already present in the soil. There are times, however, when some of these nutrients are not present in large enough quantities or aren’t available because of the high PH in our soil from the limestone in our soil.
The difference between bio stimulants and fertilizers is that fertilizers contain varying amounts of macro-nutrients, which are the three numbers that you see on the bag that you buy. These numbers represent Nitrogen (N), Phosphorus (P), and Potassium (K). There is also a very small amount of micro-nutrients. Fertilizers generally contain large amounts of the macronutrients, with very little micronutrients, while bio stimulants contain very little macronutrients, with a greater quantity of micronutrients, and also the beneficial fungi Mycorhizae. This fungi works with the root system, drawing in moisture and nutrients for the plant.
Of the sixteen essential nutrients, three of them (Carbon, Hydrogen, and Oxygen) are from water and air. These are always available, and we do not need to be concerned about them. The other thirteen are almost always absorbed by the roots. The thirteen essential mineral elements obtained from the soil are divided into three groups, based on the amount of nutrients that are needed by plants. The nutrients used in very small amounts are micronutrients or trace elements. These include boron, chlorine, copper, iron, manganese, molybdenum, and zinc. Acid loving plants have trouble obtaining iron in Austin because our soil is so alkaline. The secondary nutrients; calcium, magnesium, and sulfur, are used in greater quantity and deficiencies are more common. Sulfur is often added to good fertilizers that are sold for acid deficient soils, as a buffering agent. At Real Green, we add sulfur ourselves to all fertilizers and bio stimulants we apply. Nitrogen (N), Phosphorus (P), and Potassium (K) are the macronutrients necessary in the largest quantity. Although these nutrients are required in greater quantity, they are of no greater importance than the micronutrients.
Information On Nitrogen, Phosphorus, Potassium, pH And Compost
Nitrogen forms new cells and is essential to total plant development. Symptoms of nitrogen deficiency are a yellow-brown color along the veins and tips of leaves, stunted growth of the plant, or paleness in color on older leaves. Too much nitrogen can cause tall, spindly plants that easily topple over and nitrate poisoning (look for a strong red tint to the leaves). Nitrogen is also essential to compost piles to break down old plant residues. Good sources of nitrogen include: blood meal, cottonseed meal, fish meal, soybean meal, rabbit manure and tea grinds. You can also grow a cover crop of legumes in the fall to raise the nitrogen level for the next Spring’s crop.
Phosphorus produces vigorous seed and root development. A shortage of phosphorus slows cell division and results in stunting of growth and late maturity of the plant. A symptom of phosphorus deficiency is spindly plants with purple streaks in the stems. Since phosphorus moves very slowly in the soil, it is essential to have it available during early plant development. Good sources for phosphorus include: bone meal, rock phosphate and colloidal phosphate. Incorporating compost into the soil makes the phosphorus present available to the plants.
Also called Potash, this nutrient helps produce strong and sturdy stems. It advances root growth and helps plants resist disease and cold weather. A shortage of this nutrient causes stunting and stem weakness. Symptoms include yellow leaf edges and leaf veins. This nutrient must be available during early plant development. Good sources of potash are: cow manure, compost, granite meal, greensand and wood ashes.
pH is a measure of acidity or alkalinity on a scale of 0 to 14, with 7 being neutral. The pH of the soil affects nutrient availability, plant nutrient uptake, and microorganism activity. Because soil pH affects many factors, it’s important to maintain proper pH throughout the growing season. Considering the complexity of factors involved, the recommended soil pH for each individual variety is very important. Regular pH testing will allow you to make informed decisions if soil pH adjustment is necessary.
For soil that’s too acidic, add dolomitic limestone in the fall to raise the pH of the soil while supplying calcium and magnesium. Hydrated lime will provide quicker results because of the smaller particle size and is especially useful for raising the soil pH quickly. Be aware that hydrated lime can cause severe injury to young plants. Apply at least 3 weeks before planting. Wood ashes can also be added to correct the pH level. For soil that’s too alkaline, add powdered agricultural sulfur, aluminum sulfate or iron sulfate to the soil for a quick fix. For a long term solution, continually add acidic organic matter, such as peat moss, pine needles and oak tree leaves until the pH level is correct.
The single most important addition to any garden is compost. Compost enriches the soil, promoting the development of beneficial insect populations, helps retain moisture, and aids in stabilizing the pH level. Every gardener should have a compost pile or bin near their garden. Just about any plant material can be recycled into valuable compost, along with coffee grounds, crushed eggshells, cow manure, and horse manure. If you add lawn clipping to the compost pile, make sure they have not been treated with any chemical herbicides. In the fall, make sure to shred any leaves before adding them to the pile. Don’t add diseased plant material to the compost pile or weeds that have gone to seed.
Lawn fertilization is applied on the surface and rarely reaches the root system of a tree. Furthermore, many lawn fertilizers purchased on the retail level actually contain a post emergent herbicide. These fertilizers are called “Weed and Feed”. These herbicides are targeted towards broad leafed plants. The big problem here is that trees are also broad leafed plants, and these herbicides can cause fatalities in trees. Some trees will become severely ill after one application, while others can withstand many years of repeated applications before becoming ill. Pre-emergent herbicides should be applied when everything is dormant, while fertilizers are only effective when plants are growing.
Trees are targeted by many defoliating pests. These pests can completely strip a tree in a matter of days. A healthy tree has the ability to replace damage, as well as fight other fungal and disease problems. Without foliage, a tree has no way of feeding itself. In the past few years’ heavy rains, saturated soils, insects, and fungal problems, have wreaked havoc on our trees. This necessitates the use of all available tools that we have in our arsenal to keep the remaining trees healthy.
Test your soil, add the recommended fertilizer and/or Bio stimulant to your trees, in the proper amounts.