How Much Worm Castings to Add to Soil for the Best Garden

Earthworm castings, also known as vermicast or worm humus, are the nutrient-rich organic matter that is produced by earthworms, in the form of worm manure.  You may be asking how much worm castings to add to soil when using them as an organic fertilizer in your vegetable garden. 

How Much Worm Castings to Add to the Soil?

When deciding how much worm castings to add to soil, it will depend on the quality of your existing soil. Typically, you’ll want to aim for a concentration of earthworm castings of 10-30%.

What Are Earthworm Castings?

Simply put, earthworm castings are worm poop. They are one of the best soil amendments you can add to your vegetable garden.

How Are Earthworm Castings Made?

Pure worm castings are a natural fertilizer that is made through the digestive tract of worms.  Often, these red wigglers are fed organic waste, like kitchen scraps, which naturally produces worm manure.

What is the NPK Test Results of Earthworm Castings?

The test results of earthworm castings will show small amounts of nitrogen (N), phosphorus (P), potassium (K), calcium, magnesium, and trace minerals. The amounts will vary depending on what the earthworms were fed. The quality of what goes in effects the quality of what comes out.

How Can I Improve My Garden Beds and Soil Structure?

Adding earthworm castings to your soil is a great way to add beneficial microbes and beneficial bacteria, which will improve your soil health. The benefits of worm castings also include improving the soil structure, which increases its ability to retain water and nutrients. They also promote aeration, helping plant roots grow stronger for better plant growth. 

How Much Worm Castings to Add to Soil for the Vegetable Garden

Depending on what you are doing in the garden will determine how much worm castings to add to soil. Are you amending a whole bed? Maybe you are just transplanting or top dressing young seedlings. You’ll need to consider these things when figuring out how much worm castings to add to soil.

How Much Worm Castings to Add to Soil For Quicker Seedling Growth

The addition of earthworm castings to the top of the soil goes a long way when it comes to seedling growth. No need to worry about the fertilizer burn you can get with chemical fertilizers. The NPK of earthworm castings will gently fertilize your young seedlings.

Earthworm Castings For Stronger Root Growth 

Organic worm castings are one of the best soil amendments.  Adding them to your soil will increase aeration in the soil, which will provide more oxygen to plant roots encouraging the root system to grow big and strong. 

Improved Pathogen Suppression to Combat Plant Diseases

Earthworm castings contain beneficial microbes.  Adding these beneficial microbes by way of worm manure to your soil will naturally combat plant diseases by suppressing the pathogens that cause them.

 

Use Earthworm Castings For Improved Pest Suppression

Using earthworm castings as an organic fertilizer and soil amendment will give you healthier, stronger plants.  Vigorous, healthy plants are not usually the victim of pests in the vegetable garden.  Pests will naturally attack the smaller, weaker plants in the garden. 

Using earthworm castings in the vegetable garden makes organic pest control easier by giving you strong, healthy plants.

Get Better Plant Growth & Higher Yields With Earthworm Castings

With all the benefits of worm castings, adding them to your vegetable garden is sure it give you higher yields and better plant growth. They will improve soil structure, nutrient availability, water retention, and add the necessary nitrogen, phosphorus, potassium, calcium, magnesium, and trace minerals to your soil.

Increased Organic Matter for Healthy Soil

Increasing the organic matter and adding dry amendments to your soil improves your soil structure which will lead to better plant growth in the vegetable garden. Beneficial microbes also feed off of organic matter, which makes the addition of worm castings to your soil a good thing.

Better Soil Structure and Water Retention for Plant Growth

Improving your soil structure in one of the best things you can do for your vegetable garden.  Always be thinking of ways to feed your soil and not just ways to feed your plants. The addition of worm castings and different types of compost to your soil will improve your plant growth by enhancing your soil aeration and water retention. You may also consider if amending with topsoil vs garden soil vs potting soil might help.

Get Better Pollination for Better Production

When you create healthy soil, you will have healthier plants.  The natural result of a healthy garden is the attraction of more pollinators in your garden. More pollinators leads to a better producing garden. 

Addition of Worm Castings as a Slow-release Fertilizer

One of the best benefits of worm castings is them being a slow-release fertilizer to your vegetable plants.  Using worm castings in the garden will feed your plants slowly over time, eliminating the risk of synthetic fertilizer burn. 

Where to Use Worm Castings In Your Vegetable Garden

Earthworm castings can be used all around the garden. You can amend large planting area with worm castings. You can also add a handful of worm castings to your transplant holes. They can also be sprinkled around the base of the plant for plant health.

When To Use Worm Castings To Your Vegetable Garden

You can use worm castings anytime in your vegetable garden.  They are a great, safe way to fertilize and feed the soil at any stage of gardening.

Methods of Applying Worm Castings

Earthworm castings can be applied easily by hand for top dressing plants.  You can also apply cups of worm castings directly to your soil to mix in. 

Use Worm Castings in Your Seed Starting Soil Mix

​Pre-made seed starting mix usually does not have nutrients added to it.  Add earthworm castings to your seed starting mix to feed seedlings once they sprout. 

Use Worm Castings for Better Seed Germination

Adding worm manure to your soil provides better germination for your seeds. They improve soil structure adding more aeration.  Once your seeds germinate, sprouts will take off.

Use Worm Castings to Transplant Your Seedlings

Once you have hardened off your seedlings and they are ready to transplant, use a handful of worm castings in the planting hole.  The roots of your plants will love the extra nutrients that worm manure provides. 

Use Worm Castings to Top Dress Plants

The addition of worm castings to the base of the plant is a good idea.  This will act as a slow release organic fertilizer for consistent plant growth. 

Application Rates of Earthworm Castings

The application rates of worm castings will depend on your existing garden soil. The amount of worm castings will also depend on what you are feeding.  Some vegetable plants are heavy feeders such as, tomatoes, squash, melons, and cucumbers. 

What plants like worm castings?

All plants like worm castings. You can use them in the vegetable garden, herb garden, landscaping, and fruit trees too.

How Much Worm Castings To Add To Soil for the Growing Season

If you are amending existing garden soil, you will typically want to aim for a 10-30% addition of worm castings.  This will vary from garden to garden. It’s always wise to How Often Should I Add Worm Castings to the Soil?

In between each growing season is the best time to add soil amendments. Top dressing plants can be done a couple of times throughout the growing season to encourage plant growth.

Rejuvenate Old Soil With The Addition of Worm Castings

​Think of soil as a bank account. If you take something out you have to put something back in or there will be nothing left. Adding worm castings to your soil in between plantings will help keep it healthy for each growing season. 

Organic Worm Castings vs. Compost

Worm castings and compost are both great for the garden. Worm castings are known for their nutrients and microbial activity, while compost contributes to overall soil fertility and structure in a more balanced way.

What’s the Best Organic Material for the Vegetable Garden?

Many gardeners use a combination of both worm castings and compost for best results. Compost tends to add more bulk of organic material where as worm castings can add more nutrients.

Do I Need Fertilizer if I Use Worm Castings?

Worm castings are not a complete fertilizer. You may find that using compost along with them works well.

Always Have the Benefits of Worm Castings by Having a Worm Farm

Wouldn’t it be great to have all the benefits of worm castings readily available at all times? A worm bin is easy to set up, maintain, and are great for small spaces. 

How to Build a Worm Bin for Your Own Earthworm Castings

Making your own worm bin is easy and can be done with a ventilated container, moist bedding material such as shredded newspaper, kitchen scraps for worm food, and a handful of red wigglers. Keep your bin out of direct sunlight, between 60-80*F.

Make Organic Fertilizer With Your Own Worm Castings

Overtime your red wigglers will continue to eat the kitchen scraps, converting them and the moist bedding into worm castings. Once all the bedding is gone, push the contents of the bin to one side and add new bedding and kitchen scraps. The worms will migrate over to the new food so you can harvest the worm castings from the original side. 

How to Make Worm Casting Compost Tea

Worm casting tea can be made by simply soaking the worm castings in a gallon of water. For an added benefit you can increase the microbial activity by adding a bubbler for oxygen and some molasses for them to feed on.

Worm Castings Tea Application

Worm teas can be applied by watering the plant with the worm tea at the base of the plant. You can also apply it as a foliar spray. 

Are There Any Disadvantages Of Worm Castings?

If you need to source larger amounts of worm castings it may get expensive if you are buying them from the store. Having your own worm farm is much more cost effective. Then you wont have to worry so much when deciding how much worm castings to add to soil for the best garden.

Can You Add Too Much Worm Castings to the Soil?

Adding an extreme amount of worm castings could cause a nutrient imbalance and lower your pH, making it more acidic. Again, it would take an extreme amount. Always do a soil test before adding any amendments to your garden soil.

To Sum Up How Much Worm Castings to Add to Soil for the Best Garden

When deciding how much worm castings to add to soil for the best vegetable garden the answer is easy. Just go for it. They are a great addition to your gardening game.

Happy Homesteading & Gardening,

Jenny @ The GrahamStead Family Farm

Jenny and her family have been homesteading for over 20 years. They are currently farming on their 10 acre Florida farm, that they built from the ground up, 8 years ago, growing 100% of their meat and a lot of their vegetables. From their small herd of Aberdeen Angus Cattle, Pastured Poultry, Sheep, and seasonal pigs, they are able to raise enough meat for the family while selling extra to the community. All the while, striving to butcher at home, as much as possible, and use the bits and pieces of their harvest by preserving food, making bone broth, and (Jenny’s favorite) tanning all kinds of hides!

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