Nitrogen is an essential component of Chlorophyll, the green pigment in plant cells, which next to nitrogen also contains magnesium, carbon, oxygen and hydrogen. Chlorophyll is a vital catalyst in the production of carbohydrates by using the sun's energy in the process called Photosynthesis.
During Photosynthesis hydrogen is combined with carbon dioxide to form sugars and oxygen. The basic formula for Photosynthesis combines 6 molecules of carbon dioxide (CO2) and 6 molecules of water (H2O), interacts with each other in the presence of chlorophyll and sunlight, and converts them into 1 molecule of glucose (C6H12O6) and 6 molecules of oxygen (O2). A catalyst is defined as any substance which speeds up the rate of a chemical reaction without being chemically changed itself.
Nitrogen is also responsible for vegetative leafy growth and is taken up by plants either as nitrate or ammonium. Some plants, especially legumes, are able to absorb nitrogen from the atmosphere and transfer it to the soil.
Nitrogen deficiency manifests itself in stunt growth and pale green or yellow leaves. Older leaves, lower leaves, turn pale green or yellow first as the plant transports nitrogen from the older leaves to the younger ones.
Blood meal, an excellent source of nitrogen, can be added directly to the soil or diluted in water and applied as a liquid fertilizer. It may also be spread in granular form in garden areas to deter rabbits. Blood meal added to compost piles acts as a composting activator.
Blood meal, or any fertilizer high in nitrogen, is not recommended to be used on established plumeria plants as it may cause a growth pattern characterized by increased leaf production and thin branches. When growing plumeria plants one wants flowers to develop. As discussed in Part One of Plant Nutrients, it was bone meal added to the soil that aided in the production of flowers. This is mentioned here because both, blood meal and bone meal, are approved as soil additives in certified organic production.
Fish emulsion, widely used as an organic fertilizer, is another good source of nitrogen. It is usually composed of 5% Nitrogen, 1% Phosphorus and 1% Potassium. In addition to these three macronutrients, fish emulsion also contains micronutrients and trace Minerals. Fish emulsion also makes a fast acting foliar fertilizer.
Tropical plants with large leaves, including Alocasia, Caladium, Calathea, Canna, Colocasia, Ginger, Heliconia and others, benefit from periodic applications of additional nitrogen using fish emulsion or blood meal.
Leafy vegetables, such as arugula, lettuce and spinach and herbs, such as basil and parsley, also respond well to extra feedings of nitrogen.
Potassium, chemical symbol K (from the German word Kalium), is an important nutrient that assists the plant in regulating its cold and heat tolerance, insect and disease problems and drought tolerance.
Potassium also plays an important role in the water use of plants, called Osmoregulation. One of several functions of Osmoregulation includes the opening and closing of the Stomata, which affects the uptake of carbon dioxide and the temperature control through transpiration for the Photosynthesis process. Stomata are the minute pore openings underneath plant leaves that can open and close according to the metabolic needs of plants.
In addition, potassium regulates plant enzymes. It increases root growth and lowers respiration limiting the plant’s energy loss.
Potassium uptake is faster when the plant’s root system is in warm, moist and well aerated soil with a slightly acidic to neutral soil ph.
Potassium deficiency manifests itself in deformed, stunted or yellow leaves, weak stems and premature bud or fruit drop.
Plumeria plants and plants in general need an adequate amount of potassium in order to flourish and develop their full growth and flower potential.
When providing plants, including tropical and plumeria plants, with the three macronutrients nitrogen, phosphorus and potassium, it is important to provide plants with the correct ratio according to the plant’s individual needs.
These are the important contributions that nitrogen, blood meal and potassium make in creating a beautiful and lush garden that every gardener can be proud to showcase privately and publicly.
Part Three of this Plant Nutrients series will focus on the Secondary Plant Nutrients magnesium and sulfur as well as on the Micronutrients boron, chloride, copper, iron, manganese, molybdenum and zinc.
My name is Bob Walsh. I have been growing tropical plants in Chicago, USA, plant hardiness zone 5, for more than 20 years. The past 10-plus years I focused on developing successful growing techniques for plumerias, frangipani, both indoors and outdoors, which resulted in the publication of my step-by-step illustrated plumeria care guide, How To Grow Plumeria - Frangipani Anytime Anywhere!. This easy-to-read, easy-to-follow unique plumeria care guide simplifies the rooting and planting methods for plumerias and other tropical plants. New and seasoned gardeners alike are given everything they need with pictures and descriptions to successfully grow plumerias year round indoors and outdoors. I share with the reader my tried and tested methods which I use in successfully growing plumerias and other tropical plants year round in my home in zone 5 in Chicago, USA.
For your FREE Tropical Plant Guide, Grow Your Own Tropical Garden, visit Plumeria Plant Care.