21 Ways to Increase Soil Fertility

You were hoping for the Garden of Eden, but perhaps you ended up with a garden that looked more like the Sahara desert? Do you look at your garden beds and wonder how anything could possibly grow there?

Soil fertility might be to blame if your garden looks bleak and barren instead of lush and full.

In this article, we’ll discuss what soil fertility means, how to test your soil, and 21 ways that you can improve the fertility of your soil so that you can have the lush, productive garden that you desire.

garden soil

Soil Fertility

A healthy garden begins with healthy soil because plants need nutrients just as much as people do.

A soil that is considered fertile will have all of the nutrients needed for plant nutrition. This includes major nutrients such as nitrogen, potassium, and phosphorus, alongside of other nutrients such as magnesium, copper, and calcium, just to name a few.

Soil fertility also involves organic matter, pH, and moisture and nutrient retention. Fertile soil includes beneficial micro-organisms, minerals, and helpful insects such as earthworms that aerate the soil and provide their own manure.

One example of fertile soil is the type of soil that is found on the forest floor. Typically, this soil is a dark, brown or black color. It is loose, rich, and has an earthy smell.

Soil that is unfertile is often hard, dry, and difficult to dig. It might be pale in color, barren, and causes the water to run off rather than sink in.

Poor soil can happen anywhere. Erosion, pesticide use, compaction, overgrazing, over-farming, and even fertilization can harm the soil’s natural fertility.

Growing the same crop in the same space over time can reduce fertility and increase the presence of disease.

Another aspect of soil fertility is soil type. Soils can be clay, loam, silt, or sand. If your soil does not have a well-balanced texture to it, you’ll have trouble with soil fertility as well.

You’ll need to figure out what type of soil you have and make amendments to the texture to increase fertility.

Ideally, you want a mix of clay, silt, and sand, which makes up loam. You can use a jar test to determine your soil texture. Check out this quick test here.

Factors that influence the fertility of your soil include pH, organic matter, moisture content, and density.

If your soil is too compacted, water and air will not be able to be distributed throughout the soil. This will hamper the growth of microbes and restrict the movement of nutrients in the soil.

How to Test for Soil Fertility

You can test your soil fertility in a couple different ways. The easiest way to test for soil fertility is through your local ag extension office.

The Penn State Ag Extension will test your soil for you for a minimal fee. Using their test kit, you will send them a sample and they will return an analysis and recommendations for you to know how to improve your soil. You can see that information here.

However, if you want to do it yourself, you can buy a soil test on amazon.

The soil test will help you understand what factors are missing and what you need to do to correct the problem. You can increase overall soil fertility with the following 9 methods.

How to Increase Soil Fertility

#1. By Amending Soil Texture

If you’ve done the jar test, you’ll know what your soil texture is. If you have hard clay soil, rainwater will be more likely to run off.

Clay Soil

  • Amend clay soil by adding plenty of organic matter to the soil.
  • Continue to add compost or mulch every year to build soil texture and fertility.

Sandy Soil

  • Amend sandy soil by working several inches of organic matter into the soil
  • Continue to mulch throughout the year.
  • Use cover crops, such as oats, rye, or sweet clover, to build soil and soil fertility.

Silty Soil

  • Amend silt by turning over the top layer of soil regularly
  • Add compost or aged sawdust.
  • Avoid overwatering silty soils.

#2. Avoid Tilling

Tilling is an easy way to break up the soil in your garden. It breaks up hard clay, turns the soil over, and mixes weeds and grass down into the soil.

If you are in a hurry to turn your yard into garden, you may find that you need to use a tiller to get the process going.

However, tilling has its disadvantages. Tilling the soil can actually disrupt the natural processes of the soil systems and the result is reduced soil fertility.

First, the tiller will disrupt the natural bacteria in the soil. It disrupts the air pockets and porosity of the soil, making it impossible for the bacteria to survive.

It can also stir up dormant weed seeds, which will make their way to the surface, grow, and steal the nutrients that your desired plants need.

#3. Using a Broad Fork

To prevent this, avoid tilling as much as possible and turn to other, more fauna-friendly ways to create your garden.

If you must break up the soil, using a broadfork to open the soil up is much more friendly to the natural bacteria and insects then the tiller is. This will create more aeration in the soil where the tiller will create less.

#4. Try Lasagna Gardening

Lasagna gardening, sometimes called sheet mulching, will improve soil fertility without the need of a tiller. Lasagna gardening is layering organic materials in the area you wish to plant your garden.

This will smother the grass, make it possible to plant your garden, and attract beneficial insects and bacteria to flourish. As the organic materials break down, they will add additional nutrients to the soil, as well.

Types of organic matter that you can layer include hay, leaves, manure, compost, and yard waste. For the bottom layer, you can opt to put down plain cardboard or layers of newspaper.

After you have created all of your layers, make sure to wet them down thoroughly. After a few weeks, you should be able to create holes through the layers of your lasagna garden to plant into.

Over time, worms will break down the cardboard and newspaper along with the organic matter to create a rich, nutritious soil that will feed your plants.

#5. Mature Compost

Compost is one of the best ways to increase the soil fertility in your garden. It’s best if your compost is aged for a year before you use it, especially if it involves ‘hot’ manure such as chicken manure.

You can use a compost bin or just a pile in the corner of your yard. The key to the best compost is the right mix of carbon materials to nitrogen materials.

For best results, you want 25 to 30 parts carbon to 1 part nitrogen. Carbon materials are things like dried leaves, dried yard clippings, mulch, etc.

Nitrogen sources come from chicken manure and kitchen scraps. If you have too much nitrogen, your pile will end up being smelly and stinky.

If you have too much carbon, the pile won’t get as hot and will take much longer to decompose. You don’t have to measure, just watch the health of your pile and add carbon or nitrogen as needed.

You’ll want to wet down your pile periodically and occasionally turn it and cover it with more carbon to keep it healthy. Once the compost breaks down, you’ll have a rich source of compost for your garden.

When you first start your garden, you can use compost for layers in a lasagna garden. You can also mix compost into the top layer of soil or add some to the hole in which you plant your seedlings.

You can also top dress or side dress your seedlings with some very well-aged compost, being careful not to put it right against the stem as it could burn the plant.

#6. Buried compost

Another way to use a composting method to increase soil fertility is to bury it. If you are creating a raised bed, you can dig a trench down the middle of the bed in the fall.

Fill the trench with kitchen scraps, old hay, and even rabbit and goat manure. Cover it over, and this will act as a compost pile that will feed the soil in the raised beds, making it rich and healthy for the plants that will be planted there in the following spring.

#7. Liquid Compost or Compost Tea

Compost tea will add plenty of nutrients and beneficial microorganisms to your soil. You can purchase liquid compost or you can make your own compost tea.

Check out the guide to making your own compost tea here.

#8. Hugelkultur

Hugelkutlur is a means of creating humus and increasing soil fertility by burying large pieces of rotting wood in your garden beds.

You can also use it to help fill in raised beds without paying for large amounts of expensive garden soil.

#9. Mulching with Wood Chips

The Back to Eden community will quickly tout the benefits of mulch, and for good reason. Mulching your garden thoroughly mimics the processes that happen naturally in the forest.

The forest floor contains some of the richest, best growing soil that can be found.

Some Back to Eden experts will add a layer of mulch that is twelve to eighteen inches deep to their gardens and beds each year. Over time, the mulch will break down and create rich, dark soil underneath.

While you can find mulch for cheap or free, it is important to get mulch that is free of pesticides or chemical residue. Mulch that has been treated with herbicide could kill your plants.

Also, mulch that has been made from certain types of trees, such as black walnut, butternut, hickories, and pecan might have adverse effects on your garden.

These trees produce a substance called juglone which can kill susceptible plants such as tomatoes, peppers, egg plants, and potatoes.

If you are unsure about the mulch you are using, its best to allow it to compost for at least six months to remove the effects of the juglone.

To plant in a garden that uses the Back to Eden method, you simply push back the wood chips where you are going to plant, no matter if you are direct sowing seeds or transplanting seedlings.

After the seeds have sprouted and the seedling are established, you can push the mulch back towards the plant (being careful not to smother it).

The heavy layer of wood chips will suppress weeds and naturally improve the fertility of the soil as they wood chips breakdown.

They also create a lot of air space in the soil, which provides oxygen to plant roots and natural bacteria. This will help your soil – and your plants – to flourish.

#10. Mulching with Hay

Although hay can be used as a type of mulch, most commercially grown hay is now treated with herbicides and pesticides.

These chemicals may be detrimental to your garden, killing the helpful insects, microbes, and your plants. If you cannot find a source of organically grown hay, you may want to avoid using hay as a type of mulch in your garden.

#11. Plant Cover Crops

Another means to improve soil fertility is the use of cover crops. Cover crops are grown after the final harvest in the fall, throughout the winter if possible, or in early spring before planting time.

You can also plant them in a new area that you are preparing to garden in the next season or a space in the garden that you are allowing to rest for a season.

These crops will build up the fertility and improve the structure of the soil every season. Bare soil is prone to compaction, erosion, and loss of nutrients.

Keeping it covered with any of these cover crops will not only prevent the loss of fertility, it will also increase fertility.

First, the cover crops will fill in the field or spot and suppress weeds without herbicides. They will create habit for beneficial insects, and their flowers will attract these insects. The roots will decay and create channels in the soil to help oxygen and water to permeate the soil.

After the crop has grown, you simply ‘chop and drop’ the plants. For the least amount of soil compaction, use a scythe to chop down the cover crop and allow it to decay in place.

If necessary, you can use a lawn mower but the weight of the mower will add compaction to the soil.

Crops such as clover, alfalfa, beans, and peas (known as legumes) are nitrogen fixers that will help to balance the levels of nitrogen in the soil without chemical additives.

Grasses have complex root systems which will add more channels to the soil and can be mixed in with your legumes.

You do not need to till these crops into the soil to receive the benefits, rather, you can simply use the chopped down crops as a mulch.

Clear a small space where you will plant your seeds or seedling, much as you would in a Back to Eden garden using mulch.

The cover crops will continue to decay throughout the season, acting as compost to feed and protect your plants.

#12. Put Your Chickens to Work

Chicken manure is high in nitrogen, and if you put it directly on your plants, it could burn them. However, there is a better way to improve soil fertility with chickens. Let them do the hard work for you.

After the fall harvest is completed, allow your chickens to have free run of your garden beds. You can incorporate a compost pile into the garden, wood chips, or any other soil amendments that won’t be detrimental to the chickens.

The chickens will add manure to the soil as they run and scratch in the garden. Doing this in the fall and winter will allow the manure enough time to decompose so that it isn’t too ‘hot’ for your plants in the spring.

As the chickens scratch through the garden, they will eat weeds and weed seeds, turn the soil naturally, and scratch manure and compost into the soil.

If you have a compost pile in the garden, they will turn over the compost pile as they scratch through it, adding their own nitrogen-rich manure to the pile.

They will eat bugs and garden pests that are overwintering in the garden. The chickens will also eat leftover bits of vegetable matter, and scratch some of it into the soil, which will decompose more quickly and add to the fertility of the soil.

If you pile woodchips in the garden, the chickens will scratch through the chips, eat the bugs, and spread the pile for you.

Essentially, they will reduce the pest population, add manure and compost, and turn the soil for you. All of these actions from your chickens will result in increased soil fertility for your garden.

As a bonus, you will have reduced feed costs for your chickens and healthy eggs as they feed on what is left of your vegetables from the previous season.

#13. Plant Deep Rooted Plants

If your soil fertility is low, there are some specific plants that can help. Plants with deep tap roots can draw up minerals and nutrients from deep below the soil’s surface into the plant.

When the plant dies, the minerals and nutrients are put back into the soil near the surface where smaller plants can access them. The deep taproots also add aeration and channels in the soil that provide water and oxygen to the plants you would like to grow.

These plants include comfrey, yellow dock, dandelion, and borage. Both borage and dandelion are edible, and all four plants will bring up nutrients and minerals from deep in the soil into the plant, where they can be composted or turned under to fertilize the soil.

#14. Use Manure

Manure, or animal waste, is a natural source to increase soil fertility. Not only does manure add nutrients to the soil, it also adds humus, which increases the soil’s ability to retain moisture.

Horse manure, especially from horses bedded on hay or straw, is an excellent source of manure. Local farms often use cow manure, as well.

For the small homesteader, goat and rabbit manure are especially good options because they do not need to be composted before being added to the gardens and can be used as a top dressing as well as mixed into the soil.

Most animal manure, especially chicken manure, should be composted thoroughly before being added to gardens or beds because the high content of nitrogen in the manure can burn plants. Microbes in the feces can cause illness, as well.

#15. Avoid Harsh Chemicals

Sometimes, the use of chemicals is unavoidable. Severe insect infestations, or severe soil deficiencies in the areas of potassium, nitrogen, or phosphorous may require inorganic solutions such as herbicides, pesticides, or fertilizers to correct specific problems.

However, these types of chemical treatments may cause additional problems that reduce overall soil fertility.

For example, herbicides may kill cover crops intended to increase soil fertility. Pesticides meant to eradicate a particularly bad pest may also kill off beneficial insects and microbes that increase soil fertility.

If you are using inorganic pesticides and fertilizers, you may be inadvertently reducing the fertility of your soil.

If this is the case, you may need to choose another option to increase the fertility of your soil. Organic solutions seem to be the least disruptive means of pest and weed control.

#16. Additional Sources of Nitrogen

  • Kelp Meal can be applied directly to your soil, but it is an expensive means of adding nitrogen.
  • Seaweed contains nitrogen, potash, sulfur, magnesium, and phosphorus.
  • Blood meal is an expensive additive with a high nitrogen content. Care needs to be taken so that it doesn’t burn plants.
  • Fish meal or fish emulsion. These products are also high in nitrogen but may not be considered organic due to additives in the product itself.

#17. Sources of Phosphate

Phosphates can be added through mineral sources such as soft rock phosphate, hard rock phosphate, and colloidal phosphate. These sources work best when added to manure and allowed to compost.

#18. Sources of Calcium

  • Lime adds calcium and moderates soil pH.
  • Gypsum is a source for calcium and sulfur.

#19. Sources of Potassium

  • Granite Dust is a source of potash but it does not break down completely in your soil.
  • Glauconite is a slow-release mineral that allows potash to slowly break down into the soil. However, it is highly expensive.

#20. Try These Easy and Natural Soil Additives

There are a number of soil additives that you may have around your house or have easy access to that will help you increase your soil fertility, especially in small spaces.

Banana peels. Not only do bananas provide potassium for people, the peels provide potassium for your soil and plants. You can compost your peels or bury them in the garden to add to potassium to the soil.

Autumn leaves. Collect your fallen, dried leaves in the fall to use for mulch for your garden and flower beds. If you don’t have enough of your own, ask your neighbors and township.

You’ll save them leaf collection costs. And in return, you’ll get protective mulch cover for your plants that also contains 11 of the 15 nutrients that plants need to grow.

Coffee grounds. If you love coffee, your garden is in luck. Coffee grounds will add magnesium, copper, potassium, and phosphorus and will make your soil more acidic. If you don’t have enough coffee grounds of your own, ask your local coffee shop if you can collect theirs.

Fish manure. If you’ve got a fish tank, you’ve got fish manure. Just water the base of your plants with the fish tank water every time you change it out for a blend of nitrogen, phosphorus, and potassium to increase the fertility of your soil.

Fireplace ash. You can add some amounts of fireplace ash to your garden for a boost of both calcium and potassium.

Tea leaves. Tea leaves are a source of nitrogen for your garden.

Egg shells. Egg shells, dried out and crumbled up, will add both calcium and selenium. The sharp pieces may act as slug-repelling grit, as well.

#21. Worm castings

Worm castings are known as the black gold of gardening, because they are gentle and 100 percent organic, yet offer a host of benefits including protecting the plant from disease, increasing plant productivity and soil moisture retention, and providing minerals such as phosphorus, calcium, nitrates, potassium, and magnesium.

Because they increase the health of the plant through increased soil fertility, the plants will be more resistant to pests and disease. Worm castings are easy to find, but you can save money by farming your own worms for their worm castings.

If you are struggling with soil fertility, these measures may be enough to get you on your way to more fertile soil.

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