keep microbial nutrient relationships alive and benefit the planet with these organic fertilizers

organic fertilizers vs inorganic fertilizers

If you decide that your plants need a health boost and you decide to fertilize, it’s important to make sure that your fertilizer is organic.

Organic fertilizer feeds the microbes that build relationships with plants to deliver nutrients to them. We want to foster this relationship!

On the other hand, synthetic fertilizer decreases the need for plants to form beneficial relationships with microbes - they don’t need their nutrients anymore (teaming with microbes).

In fact, organic fertilizer actually requires soil bacteria and fungi to make the nutrients bioavailable to the plants (source).

So organic fertilzer boosts soil health and microbial communities while synthetic fertilizer disrupts the soil food web.

There are other reasons as to why we want to only apply synthetic fertilizers to our crops.

Synthetic fertilizers have a high carbon footprint because they are typically made from petrochemicals (source).

Synthetic nitrogen fertilizers alone account for 2% of global GHG emissions. To put this into perspective, that’s the same amount released from commercial aircraft globally.

Moreover, synthetic nitrogen fertilizers emit nitrous oxide, which is 265 more potent than carbon dioxide (source).

what does NPK mean?

NPK stands for nitrogen, phosphorus, and potassium, which are three essential nutrients for plant growth. They are often referred to as primary macronutrients. In a fertilizer's NPK rating, the numbers indicate the relative proportion of each nutrient in the product.

nitrogen

An essential nutrient for plant growth, especially the green leafy growth of plants. For a fertilizer's NPK rating, the N is the proportion of nitrogen within the product. Signs of nitrogen deficiency are pale to yellowing leaves and stunted growth.

Nitrogen is in the air, and some plants have a symbiotic relationship with organisms in the soil that help them to transform atmospheric nitrogen into a usable nutrient for the plant.

phosphorus

An essential nutrient for plant growth, especially stem, root, and tuber development of plants. In a fertilizer's NPK rating, P is the proportion of phosphorus within the product.

Signs of phosphorus deficiency are small and misshapen tubers or roots of root crops or purple-tinged leaves (PennState + GlobalNet).

potassium

Potassium helps with the fruiting and rooting of plants, supports water uptake, and enhances photosynthesis efficiency. In the NPK rating, K is the proportion of potassium within the product.

Signs of potassium deficiency are small and misshapen fruits or stressed plants (PDA).

what do the fertilizer numbers mean?

The numbers are how many pounds of each nutrient would be in a 100 pound bag. For example, a 4-4-4 blend has 4 pounds of nitrogen, 4 pounds of phosphorus and 4 pounds of potassium in 100 lb bag of that particular fertilizer (OSU).

other important nutrients for plant growth

In addition to nitrogen, phosphorus, and potassium, there are several other important nutrients for plant growth.

As you see in the chart above, nutrients support the plant with leaf growth, fruiting, photosynthesis, root growth, nutrient update, and seed development.

Let’s take a closer look at these secondary nutrients.

plant secondary macronutrients:

• Calcium: Calcium is essential for strong cell walls and healthy root development. You will often see calcium added to fertilizers specifically made for tomatoes, as calcium is helpful for preventing blossom end rot, along with magnesium and even watering. Calcium can help neutralize acidic soils (OSU).

Signs of calcium deficiency include blossom end rot, and browning tips of leaves (source).

• Magnesium: Magnesium helps to regulate nutrient uptake in the plant, which is why it helps tomatoes take in the amount of calcium they need to prevent blossom end rot.

Signs of magnesium deficiency might present yellow discoloration between the viens of leaves, while the veins themselves stay green. Sometimes, the leaves can even become pink and curl.

• Sulfur:  Sulfur helps a plant to produce chlorophyll, which is essential for photosynthesis. It also helps Sulfur is important for the formation of amino acids and proteins in the plant. Soil microbiota need sulfur in order to fix nitrogen for beans.

Signs of sulfur deficiency included stunted growth on young plants, and yellowing pale leaves  (source).

plant micronutrients:

• Iron: Iron helps plants to make chlorophyll and supports photosynthesis. If soil is too alkaline, iron may not be available.
• Manganese: Manganese plays a role in photosynthesis and also supports root growth. It is an essential component for feeding soil microbes that aid in nitrogen fixation.
• Zinc: Zinc helps plants to synthesize protein, grow, and make seed.
• Boron: Boron helps sugars to move throughout the plant and be turned into an energy source. It’s necessary to produce lignin in plants and helps develop roots and hardy stems.
• Copper: Copper is a part of the photosynthesis process, supports nitrogen update, and builds lignin (source). Copper accumulation is an issue in agriculture, so be sure to test your soil to see if you have a copper deficiency before application.
• Molybdenum: Supports nitrogen processing in the plant by feeding microorganisms

what are some symptoms of nutrient deficiency in plants?

You'll notice in this chart that sometimes symptoms that you see in plants need to be examined more closely before you start your fertilizer application to remedy it.

Sometimes, the symptoms are unmistakable.

For example, early maturity is a telltale symptom of nitrogen deficiency.

But other symptoms need to be looked at more closely.

stunted growth in plants

For example, stunted growth could be a sign of a deficiency in phosphorus, nitrogen, potassium, sulfur, copper, molybdenum, zinc, calcium, or boron deficiency.

The general recommendation for stunted growth could be a nice balanced quick acting NPK fertilizer, say a 10-10-10.

You could see if the plant growth improves to test out if it was indeed one of those macronutrients. If plant growth doesn’t come on, then you could know it’s one of the secondary macronutrients or micronutrients.

But there is actually some nuance to it that can help us narrow down what nutrient our plant may need.

The key is to look at our plants closely and notice if there are any other symptoms happening.

In a publication from the University of Hawaii at Manoa, author Raymond Uchida explains the following:

Stunted growth from a nitrogen deficiency would be paired with yellowing on older leaves, usually starting from the top of the leaf. If the stunted growth is seen with early maturity - for example, small stunted zucchini plants flowering, then a lack of nitrogen is likely the cause.

If the stunted growth is paired with darkened, blue tinted leaves, or purple-tinted leaves, it it likely due to a phosphorus deficiency.

Stunted growth showing up in potassium-deficient plants would also likely exhibit chlorosis on the outline of the older leaves.

Stunted growth from a boron deficiency affects the roots, and is paired with plant leaf and root misshapen. Stunted growth with a boron deficiency also will show up on younger leaves.

If the slow growth is due to a copper deficiency, it may also be paired with new leaves having a malformation. Leaves may also curl in a way that they form a concave shape.

Molybdenum-lacking plants may have stunted growth paired with yellow spots on the edges of the plant, or the yellow spots may show up between the veins of the leaves.

A zinc deficiency is likely to show up through stunted growth with plants in the fabaceae family.

yellowing leaves

Yellowing spots on leaves, or chlorosis, is something that could be treated with a balanced NPK fertilizer. This might solve the problem, but we might take a closer look at the leaves to get a better understanding of how the yellowing is presenting itself.

Uchida points out the following distinctions for yellowing leaves:

If the yellowing is appearing at the top of mature leaves, with leaves eventually falling off, it’s likely a nitrogen deficiency.

If the yellowing is around the perimeter of the mature leaves, it is likely that a lack of phosphorus is the culprit.

If the veins of the leaves are still green in appearance, and the yellowing is occuring on the more mature growth, it’s likely a case of magnesium deficiency.

In contrast, if the yellowing occurs on the youngest leaves with green veins, it could be due to a lack of iron in the soil.

If the yellowing is showing up as tiny spots throughout the leaves, adding manganese to your soil could help.

plant malformation

The plant forming in a funky way could be either a boron deficiency or a calcium deficiency.

A boron deficiency is usually seen in root vegetables, where the root is elongated, thin, and in general misshapen.

A calcium deficiency would present itself in curled, concave, or other difference from the norm happening in the youngest leaves.

white leaves

Leaves that are so pale, they almost look white could be a sign of either a iron or magnesium deficiency.

Uchida describes the following distinctions:

If the whitened leaves are presenting themselves on new growth with otherwise normal leaf formation, it’s likely that iron is the issue.

If the whitened leaves are showing up deformed, or plants are stunted that would point to a lack of copper as the root cause (source).

our top picks for organic fertilizers:

As a homesteader and gardener, I understand the importance of using high-quality organic fertilizers to maintain soil health and promote thriving plants.

That's why I've personally worked with each of the following products and can confidently recommend them to anyone looking to enhance their gardening practices.

These fertilizers provide a host of benefits, from boosting soil health and microbial communities to avoiding the GHG emissions and pollution from synthetics. All of them are OMRI listed for organic agriculture.

If you're looking to take your gardening to the next level, consider trying one of our top picks for organic fertilizer in 2024.

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this one rocks: organic plant magic

fast acting complete nutrients powder

it features:

• fast acting
• added calcium
• so many secondary macronutrients and micronutrients!
• includes beneficial bacteria and fungi
• added bonuses like humic acid and amino acid
• versitile: can add to water, place in planting hole, or add to soil
• only need a small amount per plant

check it out here

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other organic fertilizers for vegetables that we use and love!

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affordable organic vegetable fertilizer, in pelletized form:‍

Nutri-Rich 4-3-2 Fertilizer Pellets (50 lb)

• 4N-3P-2K, also contains 7% calcium
• the pelletized form is great for applications on a windy day, where standard powder fertilizer would blow around
• does stay on surface and takes a few watering applications to visibly break down

‍purchase here

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well-rounded and balanced vegetable fertilizer:‍

Down to Earth Vegetable Garden Fertilizer 4-4-4 (25 lb)

• 4-4-4 is a great choice for applying to almost any vegetable
• also contains calcium, magnesium, and iron

purchase here

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best organic fertilizer for seedlings to use when transplanting (high phosphorus):

E.B. Stone Sure Start 4-6-2

• 4-6-2 is great for leaf and root development
• addition of mycorrhizal fungi helps plants create beneficial relationships with fungi at the root level
• perfect for helping plants to get established if you apply it to the transplanting site and then again 2 weeks afterwards

purchase here

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worm castings:

Peaceful Valley Organics Premium Earthworm Castings

Numerous studies have shown that vermicompost produces end yield and plant health results similar to chemical fertilizers, and sometimes even surpasses them (source). It also helps to enhance soil microbiology.

A study in 2020 found that vermicompost and vermicompost tea can effectively substitute synthetic fertilizers while also decreasing pest and disease, leading to an additional benefit of a reduced need for herbicides and pesticides (source).

Vermicompost is also a great way to keep green waste out of the landfill, as it’s what the worms will eat to make their castings.

purchase here

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top fast acting organic liquid fertilizer:

Peaceful Valley Organics All Purpose Liquid Fertilizer

• 3.7-2.7-3.7 is a great balanced liquid fertilizer that you can give to any vegetable
• doesn’t burn plants like how other liquid fertilizers might
• can add to fertigation systems

purchase here

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organic fertilizers - build fertility while supporting the planet

By choosing organic fertilizers over synthetic ones, you're not only helping to maintain healthy soil, but you're also reducing your carbon footprint and contributing to a healthier planet. Understanding the role of NPK and other essential nutrients for plant growth is a crucial step in selecting the right fertilizer for your garden. Our top picks for organic fertilizers in 2024 offer diverse benefits, from fast-acting formulas to slow-release options that promote long-term soil health. With these organic fertilizers, you can boost your garden's fertility while supporting a more sustainable future.

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