To grow, develop, and produce at their best, plants need ready access to 20 essential plant nutrients. In managing all the elements that contribute to healthy soil, gardeners often get fertility wrong.
Your hosta will be healthier and more productive if you give them what they need, not more, and not less. Natural fertilizers of organic origin best serve nature because they complement the soil’s essential biological activities more.
The basic premise of fertilization is to replenish the soil with parts of the twenty essential elements plants need to grow. Some of these elements, like carbon, oxygen, and hydrogen, can come from the air.
The gardener’s much-loved nitrogen is available to the plant from the air and soil, with the earth’s atmosphere made up of 80% nitrogen.
The majority of the plant’s nutritional requirements are absorbed from the soil via the roots. The importance of each element varies, but all play a role in plant growth, and each one’s availability varies.
Essential Plant Nutrients
|Nutrient Category||Element||Uptake As||Availability||Function|
|Primary||Carbon||CO2 and HCO3- (Carbon dioxide and bicarbonate)||Uptake from air and water||Plant Structure|
|Oxygen||H2O (Water)||Uptake from air and water||Energy production, plant structure, respiration|
|Hydrogen||H2O (Water)||Uptake from water||Synthesis of sugars, pH regulation|
|Nitrogen*||NO3– (gas) and NA4+ (ammonium – a product of ammonia and water)||Air and soil – deficiency related to low organic matter||Protein, chlorophyll, cell formation|
|Phosphorus||H2PO4-; HPO42-; PO43- (dihydrogen phosphate and phosphate)||Roots||Fat, carbohydrates, and protein metabolism, cell formation|
|Potassium||K+ (Potassium Ion)||Roots||Enzyme activity and water regulation|
|Secondary||Calcium||Ca2+ (Calcium Ion)||Roots||Enzyme activity, root permeability|
|Magnesium||Mg2+ (Magnesium Ion)||Roots||Motabolism, fat formation, chlorophyl|
|Sulfur||SO42- ( Sulfate Cation)||Roots||Protein, lipids, and vitamin formation|
|Micro||Iron||Fe2+ Fe3+ (Iron Ions)||Roots||Enzyme development & activity|
|Zinc||Zn2+ (Zinc Ions)||Roots||Enzyme activity|
|Chlorine||Cl– (Chlorine Cations)||Roots||Enzyme activity, cell development, chlorophyll|
|Manganese||Mn2+ (Manganese Ion)||Roots||Enzyme activity and pigmentation|
|Boron||H3BO3; BO33-; B4O7 (Boric acid, borate cation, tetraborate)||Roots||Enzyme activity|
|Copper||Cu2+ (copper ion)||Roots||Enzyme activity|
|Molybdenum||HMoO4-; MoO42- (molybdenum cations)||Roots||Enzyme activity and N fixation in legumes|
What Does Soil Fertility Mean?
It is essential to understand that added fertilizer cannot compensate for unproductive soil because it is excessively stony or has a subsoil layer that restricts normal root growth and development.
Soil fertility is a component of soil productivity strongly influenced by management practices.
Other components of soil productivity, especially soil depth, generally remain unchanged.
Together with climate, these components set the soil productivity limits, above which yields cannot be obtained even with the correct use of natural fertilizers or synthetic fertilizers.
What is Natural Fertilizer?
Natural fertilizers are organic materials with high natural levels of nitrogen, phosphorus, potassium, or other essential plant nutrition elements—the list below is from the National Center for Appropriate Technology and USDA’s Rural Business-Cooperative Services are common natural fertilizer examples.
Some Natural Fertilizers
|Material||% N||% K||% P||Release Rate||Comments|
|Alfalfa Meal||2-3||1-2||2||Slow||Source of Micronutrients|
|Bat Guano||0-8||0-10||0-1||Medium to Fast||Quality depends on the source|
|Blood Meal||12||0-2||0-1||Medium to Fast|
|Bone Meal||2-4||14-16||0||Slow to Medium||Rich in calcium (20 to 24%)|
|Coffee Grounds||3||Will reduce nitrogen availability due to high carbon content (11:1)|
|Cottonseed Meal||4-6||2-3||1||Slow to Medium||Acidic|
|Crab Shell Meal||4||3-4||0||Slow||Rich in calcium (14 to 18%)|
|Fish Hydrolysis||2-5||3-4||1||Medium to Fast||promotes beneficial fungi microorganisms|
|Greensand||0||0||0-5||Very Slow||Source of K, Mg, Fe, Si, and trace minerals|
|Kelp Meal||1||0-1||2||Slow||Source of micronutrients|
|Rock Dust||0||0||3-6||Very Slow||Source of Ca, Si, and trace elements|
|Rock Phosphate||0||3||0||Slow to Medium||20% P2O5 with 20% Ca and trace elements|
|Soybean Meal||2||1||7||Slow to Medium|
|Sul-Po-Mag||0||0||22||Slow||22% sulfur, 11% magnesium|
|Vermicompost||2-3||2||2||Medium to Fast||Adds essential soil microbes|
|Wood Ash||0||1-2||4-10||Medium||Do not add ash to nitrogen applications. Produces ammonia gas|
This list shows that natural fertilizers are organic; they are made from renewable carbonaceous plant or animal products. In contrast, mineral fertilizers are in the form of inorganic salts obtained by mining or chemical industrial processes.
Not all chemical industrial processed fertilizers are inorganic, though. A byproduct of biogas production is an organic residue, also known as digestate.
Anaerobic Digestate (AD)
Most off-the-shelf organic fertilizers are a byproduct of biogas production. Food waste, maize, and manure biodigesters use anaerobic bacteria to decompose the organic materials in a sealed environment, producing methane gas and a nutrient-rich residue.
During the breakdown of the organic matter, the essential plant nutrients (N, P, and K) remain in the digestate.
Anaerobic digestion is a pretty remarkable process as it is achieved without substantially reducing the fertilizing properties of the feedstock material.
However, unlike aerobic composting, anaerobic digestion does not reach temperatures sufficiently high to destroy pathogens and weed seeds. There is, therefore, a possibility that AD can contain some disease contaminants.
Is Epsom Salts a Natural Fertilizer?
Epsom salt was found in the English town of Epsom. It’s not the kind of salt we’re used to seeing. Epsom salt is made up of magnesium, sulfur, and oxygen and is a mineral salt, and it is very soluble in water and swiftly breaks down into magnesium and sulfur.
While it’s a naturally occurring material, it is mined or produced and is not an organic fertilizer.
Like other mineral fertilizers, it can contribute to a build-up of salts in the soil, and the added sulfur can decrease the soil’s pH (more acidic). Remember the rhyme; sulfur suppresses, lime lifts.
It is exceptionally leachable in sandy soils due to its soluble nature, and it may quickly leach past the root zone and become inaccessible to the plants. Adding compost can help reduce the loss by increasing the cation exchange capacity.
What is the Advantage of Using Natural Fertilizer on Hostas
It’s always a good idea to focus on boosting nature’s ability to regenerate itself. Any interaction with nature should be transactional using nature’s currency, and natural fertilizer is nature’s currency, providing your soil with the means to self-improve its health.
Soil should be a vibrant ecosystem of living organisms, roots, hyphae, and plant nutrients. Healthy soil smells good because of the life in it, marked by the presence of geosmin [from the Greek, geo (earth) and osme (odor)].
Added synthetic chemicals generally target plants, ignoring the impact they may have on the surrounding fragile ecosystem – a system responsible for the symbiotic sustainability of everything that benefits plants.
Hostas are not heavy feeders and will get every nutrient they need from bone meal in powder or liquid form.
Coffee grounds are an excellent slug repellent as a thin mulch Less than an inch) will boost the presence of other beneficial microorganisms. It’s important to note that contrary to belief, coffee grounds are pH neutral and ideal for hosta plants.
What Are the Disadvantages of Using Natural Fertilizers on Hostas
The disadvantage of using natural fertilizers are minimal, specifically on hosta plants. Hosta plants need a mere two ounces of nitrogen per 125-square-feet annually, and two ounces is 12.5% of a pound, so that any nitrogen-high natural fertilizers will work.
List of Some Natural Fertilizers for Your Hostas
Per 125-square-foot bed, you can add any of the following:
- One pound of blood meal
- Three pounds of bone meal
- One pound of feather meal
List of Natural Fertilizers That Need Close Monitoring with Hosta Plants
Coffee grounds are great as a compost additive, but adding them directly to the soil will bind the nitrogen as microorganisms use it to decompose the carbon. However, as a thin mulch, coffee grounds are excellent slug repellents that prevent weeds, attract earthworms and more.
Coffee grounds also contain compounds that help suppress some plant disease-causing microbes.
You may have heard that wood ashes may be utilized as a potassium source for plants in the garden. However, because wood ashes raise the pH of the soil and necessitate additional measures, they should be used in the garden with caution.
Whether you burn hardwoods (such as oak) or softwoods (such as pine) affects the fertilizer value and liming impact of wood ash (e.g. pine).
The potassium content of wood ash is typically 4 to 10 percent while the phosphorus content is 1 to 2 percent. Hardwood ashes contain larger percentages of nutrients and have a stronger liming impact on soil than softwood ashes.
In this article we looked at the different natural fertilizer components, their value, and risks. Using natural fertilizers in your garden is a healthy practice that boosts your soil’s ability to rejuvenate itself.