Healthy soil is the foundation of every thriving garden – but many gardeners don’t realize that some plants act as natural fertilizers.

These “soil-enriching” plants work quietly underground, pulling nitrogen from the air, breaking down minerals, improving soil structure, and feeding beneficial microbes.

Over time, they reduce the need for synthetic fertilizers and create a self-sustaining ecosystem where plants grow bigger, faster, and with fewer problems.

These soil-enhancing plants are also called dynamic accumulators, nitrogen fixers, or green manures, depending on how they help your garden.

Here are the top plants that practically fertilize the soil for you, along with how they work and the best ways to use them in your garden.

Why Some Plants Act as Natural Fertilizers

Nature has a built-in nutrient cycle, and certain plants play a major role in maintaining it. These plants enhance soil in three key ways:

1. Nitrogen Fixation

Some plants (mostly legumes) pull nitrogen directly from the air and convert it into a form the soil can use. This reduces the need for nitrogen fertilizers.

2. Deep Root Mining

Plants with long taproots pull nutrients like calcium, magnesium, and potassium from deep underground and bring them closer to the surface.

3. Organic Matter Contribution

When these plants shed leaves or are chopped and laid on the soil, they break down into a nutrient-rich mulch.

4. Microbial Activation

Their roots feed beneficial microbes that release nutrients locked inside the soil.

Together, these actions create rich, fertile soil – naturally, and with very little work required.

1. Clover (White, Red, or Crimson)

Clover is one of the most powerful natural soil builders. As a legume, it fixes nitrogen through special bacteria living on its roots.

How it fertilizes the soil

• Adds nitrogen as it grows
• Improves soil texture and moisture retention
• Creates a living mulch that suppresses weeds
• Feeds pollinators and enriches biodiversity

Best uses

Plant clover between vegetables, under fruit trees, or as a lawn alternative. When mowed or chopped, it becomes an instant nitrogen-rich mulch.

2. Comfrey (Especially Bocking 14 Variety)

Comfrey is a legendary dynamic accumulator with a deep taproot capable of mining nutrients from several feet below surface level.

How it fertilizes the soil

• Pulls up potassium, calcium, nitrogen, and trace minerals
• Provides nutrient-rich leaves for mulch and liquid fertilizer
• Breaks down quickly, feeding soil organisms

Best uses

Use comfrey leaves around tomatoes, potatoes, squash, and roses. Create comfrey tea by soaking chopped leaves in water for a powerful homemade fertilizer.

3. Beans and Peas (All Legumes)

Beans and peas are excellent nitrogen fixers, making them perfect companions for many vegetable crops.

How they fertilize the soil

• Convert atmospheric nitrogen into plant-available forms
• Enrich the soil for crops planted afterward
• Improve soil structure with fibrous roots

Best uses

After harvesting beans or peas, leave their roots in the soil – they continue enriching it even after the plant dies.

4. Alfalfa

Alfalfa is another deep-rooted plant that mines phosphorus and potassium while fixing nitrogen.

How it fertilizes the soil

• Adds nitrogen
• Breaks up compacted soil
• Brings minerals to the surface
• Provides leaves that decompose into high-quality mulch

Best uses

Great for cover cropping and preparing new garden beds.

5. Mustard Greens

Mustard greens are nutrient accumulators that enrich soil and also act as a natural biofumigant.

How they fertilize the soil

• Pull up sulfur, potassium, and micronutrients
• Improve soil fertility when turned into the soil
• Reduce harmful soil pathogens

Best uses

Plant mustard in fall or early spring as a green manure.

6. Lupines

Lupines are beautiful ornamental flowers that also fix nitrogen and improve poor soil.

How they fertilize the soil

• Add nitrogen with their legume roots
• Improve drainage in heavy soils
• Feed beneficial insects

Best uses

Grow lupines in flower beds, borders, and cottage gardens to improve soil fertility long-term.

7. Buckwheat

Buckwheat is a fast-growing plant that accumulates phosphorus – a nutrient often lacking in garden soil.

How it fertilizes the soil

• Pulls phosphorus from deep in the soil
• Breaks down quickly as mulch
• Improves soil friability
• Attracts pollinators

Best uses

Use buckwheat as a summer cover crop and turn it into the soil before planting heavy feeders like corn or squash.

8. Yarrow

Yarrow is a powerful dynamic accumulator and herbal plant with incredible soil-building abilities.

How it fertilizes the soil

• Pulls calcium, copper, and phosphorus
• Increases beneficial microbial activity
• Creates nutrient-rich compost when its leaves are added

Best uses

Add yarrow to compost piles or grow it around fruit trees.

9. Nettles (Stinging Nettle)

Despite their sting, nettles are nutrient powerhouses and one of the best green manures you can grow.

How they fertilize the soil

• Accumulate nitrogen, iron, magnesium, and silica
• Make exceptional compost and liquid fertilizer
• Boost chlorophyll production in nearby plants

Best uses

Harvest nettles with gloves and use them as mulch or make nutrient-rich nettle tea fertilizer.

10. Radishes (Especially Daikon Radish)

Radishes – especially long-rooted daikon – break up compacted soil and pull nutrients upward.

How they fertilize the soil

• Decompact soil naturally
• Increase drainage and root penetration
• Release nutrients as their taproots decompose

Best uses

Great for preparing garden beds for spring vegetables.

11. Vetch (Hairy Vetch or Common Vetch)

Vetch is an aggressive nitrogen fixer and cover crop commonly used on farms.

How it fertilizes the soil

• Adds large amounts of nitrogen
• Prevents erosion
• Provides thick biomass that enriches soil when cut down

Best uses

Use vetch before planting vegetables like tomatoes, corn, and leafy greens.

How to Use These Soil-Building Plants in Your Garden

1. Plant Them as Cover Crops

Great during off-seasons to enrich soil naturally.

2. Use Them as Living Mulch

Plant around fruit trees, shrubs, or vegetable beds.

3. Chop and Drop

Cut the plants and let them decompose on the soil surface.

4. Add Them to Compost

Comfrey, nettle, and yarrow speed up composting.

5. Use Their Leaves to Create Homemade Fertilizers

Comfrey tea and nettle tea are excellent for heavy feeders.

Why Soil-Building Plants Work Better Than Synthetic Fertilizers

While chemical fertilizers offer quick results, they don’t:

• improve soil structure
• feed beneficial microbes
• increase long-term fertility
• protect earthworms
• support natural nutrient cycles

Soil-building plants create a deeper, healthier foundation that benefits your garden year after year – without chemicals.

If you want a thriving garden with richer soil, healthier plants, and fewer fertilizer needs, these soil-enriching plants are your best allies.