Worm Casting: How To Make And How To Use

One critter that has dug its way into the team’s heart at Plantly is worms, and soon you will understand why. Worm castings are powerful and allow you to transform your entire garden naturally.

So, today we want to share our vermicomposting guide with you. We will share the benefits and how you can use these worms with your kitchen scraps to create organic matter to feed your garden.

The Vermicomposting Process


We are sure you have heard the term worm castings in many of our articles. These castings you get using a vermicomposting process. It is the consumption of organic waste made possible by earthworms and beneficial microbes.

Hence, they produce a humus-rich organic matter, microorganisms, with worm castings. The organic matter the worm consumes and travels through its digestive system. It is then extracted as a bacteria-enriched cast with a pill shape.

So, it is the worm poo coated with a mucus-filled healthy bacteria. You need not invest in worm castings bought online as you can produce small amounts at home. Still, you can mulch larger quantities if you have the space available.

You can do this with the vermicomposting system or use windrows or adaptions of one. Yet, you may wonder what the difference is between composting and worm castings.

Composting and Worm Castings For Potted Plants

A fantastic thing about worm castings is that you can add them to the soil as an addition to the compost you use. Hence, you can add it to the garden soil or existing plants.

Worm castings are similar to composting as you need water, air, greens, and browns to make vermicompost. But for vermicompost, you need another essential ingredient the worms.

Also, vermicompost holds moisture as it has a high concentration of humus with carbon-based substances to keep the soil hydrated yet spongy for aeration.

When you combine it with a high level of nutrients, your vermicompost is more valuable than the compost you find in the garden.

While you can purchase worm castings as compost anywhere, it has a higher price tag, and it is better to make your bin at home. Hence you can save money on homemade worm castings.

As living creatures are in the bin, it needs to remain cool compared to making compost that requires heat.

The heat helps to decompose material to kill weed seeds, pathogens, and other concerns with compost.

Hence, your vermicompost might still have some pathogens with tiny bugs inside but all worth it for you and your plant babies.

Will Any Earthworm Castings Do

earth worm for worm casting

When you look at worms, not all are born the same. So, going outside when it rains to collect worms from the sidewalk for your bin is not an option. Thus not just any earthworm castings will do.

No, it would be best if you used hungry worms that will enjoy your kitchen scraps. We are talking about the Red Wigglers used for vermicomposting. These worms do not enjoy munching on soil and survive on the decomposing manure, leaves, and other materials to thrive in the bin.

Another popular one is the red worms. These worms enjoy similar conditions but travel further down in a bin and reproduce slower. Still, they are happy to eat and create castings for your worm farm.

Preparing a Vermicomposting Bin or System For Your Worm Farm


It would be best to satisfy your worm kings’ needs to create a suitable home. First, they need brown, known as the bedding, to live, and they will eat it as well. Then they need greens that are your garden waste to kitchen scraps to feast on.

Next, they need water made available through the kitchen scraps. Lastly, they need air in the bin using loosely packed material with air holes. Then follow the DIY vermicompost bin steps that follow here.

Once your container is ready, the worms will multiply and get down to business.

You need not expand the bin often and do not need to worry about removing or adding more worms. These creatures self-regulate as they stop multiplying when the food space runs low.

DIY Vermicompost Bin

So, if you want to boost your plants with worm casting, build your small vermicompost bin packed with power. Or you can invest in one online.

Equipment Needed:

  • Hammer, nails, and a power drill

  • Two nesting plastic containers with one needing a lid

  • One shallower container with the same width

  • Eight by 2-3 inch square wooden blocks to use as risers

  • Dry material like straw, leaves, or shredded cardboard/newspaper

  • Some kitchen scraps


  1. Use the hammer with nails or your power drill to make holes at the bottom of your two nesting bins. Then make air holes on the side of the bins and along the perimeter where your containers overlap. These holes also act as drainage holes in the bottom bin.

  2. Take some dry bedding to fill one of your tall bins a third full and wet it down to feel like a wrung-out sponge.

  3. Place the worms in the corner and top it with four cups of kitchen scraps roughly chopped.

  4. Next, layer dry bedding but leave it dry and do not wet it.

  5. Place the four wooden risers in your shallow bin allowing room for the leachate to drain out. Set down your middle mid on the risers. Then add four more risers to that bin.

  6. Finally, place the worm bin on that one and add the lid.

Feeding the Worms and How to Harvest Worm Castings


Now think of your worms as raw vegans enjoying gluten-free food. These worms do not just eat anything but love to gnaw on eggshells, raw vegetable scraps, flowers, coffee grounds, and green leaves. For kitchen scraps, you will have to exclude the following from your bin:

  • Dairy products

  • Meat and Bones

  • Cooked Food

  • Vinegar and Oil

  • Citrus and Juicy Foods like Watermelons and Tomatoes

  • Any Plant Seeds

The worms need a balanced diet to remain healthy. So, when you feed the worms, ensure that 20% of the food is not only made up of one material and mix it up. With the DIY bin provided, collecting the worm castings is easy.

So, when you are ready to collect the worm castings, the best is to stop feeding the worms for a couple of weeks. Then, when you notice all the kitchen scraps digested, remove the top dry layer of bedding.

Then move the worms to the middle bin and set it with new bedding and kitchen scraps as you did at the start. But now you leave the worms out. Place the new bin on the one with the worms and the castings.

What happens is that the worms migrate through the holes to reach the bin with the food. Hence, you have a clean supply of castings for your plants. You can harvest the casting every four months for your garden.

Maintaining Proper Conditions for Worm Activity

worm casting @dougbeckers worm casting @dougbeckers

As with caring for your plant babies, you need to keep proper maintenance for your worm bin as well by doing the following:

  • For the worms to live, it helps to alternate where you place food scraps in the bin. You can do this by weekly changing the corner you put the food. You will notice that worms will, in a month, eat up the first corner of the scraps.

  • If you notice a foul odor, it is a sign that something has gone wrong. Ensure to check all the corners where you placed the food. When you have a lot of acidic material, it changes the pH, and the worms will migrate to the opposite side. Remove the material causing the problem and replace the bedding as needed.

  • If fruit flies are a concern, it helps to avoid using sweet-smelling scraps like fruit and keep the bedding on top of the food. Alternatively, you can make a fruit fly trap to lay on the bedding to capture them.

  • Lastly, keep your worm farms out of direct sunlight, as the bin needs to remain cool inside for harvesting worm castings.

Benefits of Worm Casting

Using worm castings has loads of benefits for the soil and your plants. Still, not all worm castings you find are the same.

Many factors can influence worm castings, from feedstock, proper storage, handling practices, maintenance, and climatic conditions.

But academic literature still makes a compelling case that it is beneficial for the soil and plants by doing the following:

Soil Fertility and Structure Improvement

fertile soil

Adding worm castings to the soil you get an increase in organic matter similar to adding manures. Organic matter is a food source for fungi, bacteria, and essential beneficial microbes. Hence, the organic matter must comprise 5% or more of healthy soil.

Hence, it will improve soil structure, and worm castings are suitable for water retention as they feed the breathing ecosystem underneath your feet. In addition, the worms’ castings help with soil aggregation as they work as glue to keep soil particles like clay, silt, and sand soil sticking together.

Adding a 1% increase in organic matter allows one acre of soil to hold more gallons of water. Hence, the ground becomes more absorbent, preventing runoff, keeping nutrient-rich fertilizers in the soil, and preventing topsoil erosion.

Lastly, the microbial life found within vermicompost helps turn organic nitrogen into ammonia and then nitrates for your plants to absorb. So, use worm castings in your potting soil or planting hole to keep the soil healthy.

Plant Growth Promotion and Disease Resistance

healthy plant

Worm castings help with faster germination for the best seedling growth. Studies show that 20% worm casting by volume must be used in your seed starting mix. So use it for germinating seeds faster.

Once germination occurs, studies show that it helps increase the growth rate as the soils are amended with biologically-active vermicompost.

The seedlings develop a more robust root system that pumps nutrients and water to the rest of the plant. As a result, the roots grow thicker and even fan out further into the surrounding soil. It also helps make your indoor or outdoor plants more disease-resistant.

Furthermore, worm castings help defeat soil pathogens like pythium as it acts as a smoke screen. The same applies to insects attacking plants, as worm castings repel unwanted pests like mealybugs and aphids.

It has enzymes like Chitinase that break down chitin, a glucose derivative that forms the backbone of the insect exoskeletons. Studies show that up to 40% lower incidence takes the place of hard-shelled pests when soils are treated with vermicompost.

Healthy Plant Growth

healthy tomato

As the worm castings add essential nutrients making the soil nutrient-dense, you can expect healthier and bigger yields. For example, strawberries grown in castings yield higher when grown in 10-20 present vermicompost mixes.

Even pollination takes place more effectively when soils are treated with vermicompost. The reason is that the bees take less time to discover and visit the plants frequently. So, with the information on how beneficial they are, get your worm population started.

Tips for Using Earthworm Worm Casting Effectively

When using worm poop, it helps to know how and when you need to apply worm castings.

Application Rates and Timing

To use worm castings, there is no defined application rate compared to using synthetic fertilizers. On the other hand, the majority of literature available suggests that organic material needs to make up 10% of the medium you use.

So, if you have a 10-gallon potting mix, then one gallon of worm castings should do. When approaching 20% rates, you will reach a diminishing return, which will not provide added benefit.

Furthermore, results will also depend on your potted plants‘ growth stage and the quality of vermicompost you apply.

Incorporation Methods

There are many ways to use worm castings; one of the biggest ones is fertilizing existing plants. Still, there are many other ways to use worm poop.

Using Worm Casting as a Top Dressing

worm casting application

Using this method, you can use worm castings directly on top of the soil. All you do is sprinkle a handful around the area where the root growth is in the ground. The nutrients filter down when you water and feed your plants. Using this technique does not need mixing or measuring.

You can do this every few months or when it rains to deliver the organic minerals and vitamins your plant needs.

Incorporating Worm Casting in Compost Tea

If you decide to invest in worm castings, it can become expensive, but you can make your castings go a long way. You can make liquid fertilizer of the leftover castings called actively-aerated compost tea.

Place the castings in a tightly-woven mesh bag in water and brew them for 48 hours. The water becomes agitated to introduce oxygen into the system to help feed the beneficial microbes.

Worm tea brewing often features kelp meal, alfalfa, or fish hydrolysate as a food source if you want to boost the microbe population. You can apply the worm-casting tea as a foliar spray or liquid fertilizer to drench the roots, but it needs to be used up within hours of brewing.

In this form, it works faster and is a potent fertilizer that does not burn the roots, while adding worm castings directly to the soil gives off a slow release of nutrients.

Lawns and Turf

Another beneficial way to use worm castings is to apply them directly to the lawn or turf. Still, the suggested rates are one pound per square foot, making it expensive. Hence, applying it as a worm tea might be a cheaper solution.

Some Applications of Worm Casting in Gardening and Agriculture

When you look at using worm castings, you find more people using them for agriculture and gardening.

Used For Seed Starting and Transplanting

Whether you want to start growing annual flowers to vegetable seeds before that time, you can use worm castings for germinating seeds faster.

Yet, each seedling should only receive a pinch of castings. The same applies when transplanting; you can add one to two teaspoons to a planting hole.

You can add a cup full to the hole for mature transplants to help reduce transplant stress.

Container Gardening and Raised Beds

You can use castings or raised beds for established plants in your container gardens. But you will need to add one to two cups to the soil.

Organic Farming and Sustainable Agriculture

More organic farmers are turning to sustainable farming and use worm castings to slowly release the nutrients into the soil for their fruit and vegetables.

Remediation of Degraded Soils

Neither should you throw away your old soil, as you can add worm castings and watch it come back to life. In a few weeks, microbes will do their magic as they break down the organic matter to re-establish it in living soil. Another reason is that the worm castings have a neutral pH, and you need not concern yourself about the soil balance.

Final Thought

When shopping for any fertilizer, especially synthetic ones, it can burn the plant’s roots leading to negative results. Alternatively, you can make your compost tea with random stuff. But one of the best ways is to use organic worm castings, as you can cast your worries aside.

Frequently Asked Questions

The only downside is that a worm farm can take several months before harvesting worm castings. Still, buying it can be expensive compared to your compost or homemade vermicompost.

Yes, it is an excellent fertilizer as it is 100% natural, and it helps amend the soil and leads to healthy root growth.

You can use worm castings combined with fertilizer, but neither is a substitute for the other. Using organic fertilizers helps with flower and fruit development, while worm castings help with soil quality and plant growth.

Worm castings can last up to six months, depending on how you store it. The best is to keep it away from UV lights or the sun and grow lights.

When you add worm castings to your coco coir, it adds valuable nutrients and works well in a non-fertilized coco coir.

The standard ratio is 1:4; hence one part worm castings and four parts soil. The recommended thing is to only add a pinch of worm castings for each seedling when starting seeds.

Whether you want to buy, sell, or simply reach out to other plant enthusiasts, Plantly is the right place to be!

Leave a Reply

Your email address will not be published. Required fields are marked *

Plantly Menu