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Earthworm Naturals Worm Castings Are Better. How Do We Know?

Because we test. And test. Then test some more. We grow things. In our garden and in our home. In the real world.

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Earthworm Naturals Are Designer Worm Castings

Superb Worm Castings are no accident. It is all about the process.

The inputs. The time. Correct moisture. Proper storage. Then bagging on demand.

Earthworm Naturals Castings Are Not Like "The Competition's"

No 14 day "bucket to bag" worm castings here.

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Women with blueprint plans

The Earthworm Naturals Process

When we start a new worm bed...we have a plan.

The plan is to create an environment that our composting worms will

thrive in AND produce great worm castings


Earthworm Naturals system and inputs are proprietary but we can tell you this. Our main ingredient is pre-composted horse manure. Horse manure is an exceptional bedding and food source for composting worms. It is one of their natural habitats. To this, we add many additional foods and natural supplements.

Why Vary The Inputs?

Testing and research have proven that varying many inputs creates a very diverse worm casting. We are going to put our "Geek on" for a minute. So, don your lab coats because this is important. Diverse castings have a wide array of different bacteria, fungi, flagellates, beneficial nematodes, amoebae, and ciliates.

microscope and plants

Why Are Diverse Castings Important?

Earthworm Naturals worm castings are going to grow your plants better because they have a diverse profile. Different plants thrive on different bacteria and fungal profiles. Composting worms feed on whatever is in the worm bed. To simplify, what goes in must come out. The infamous 14 day "bucket to bag" castings have 2 inputs; peat moss and cornmeal. Do you think this will create a diverse array of bacteria and fungi? This brings us to the next point.

Are Earthworm Naturals Worm Castings OMRI-listed Organic?

They Are Not. Why?

OMRI Regulations and Cost

Last check, to be OMRI-listed, the cost was $400.00 per ingredient plus testing costs. That is fine if you are producing huge batches and have 2 inputs.

It is easy to pay the money and have your product listed.

What if you produce small batches of worm castings and have a dozen inputs? This creates good castings but no one can afford them.

If you want to create quality worm castings with diverse inputs, the OMRI regulations are too cost-prohibitive.

We use all-natural inputs to create our worm castings. Do we feel our worm castings are superior to most organic brands?

You better believe we do! We dare you to compare. Try a bag of ours versus theirs. You will be back in a hurry!


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Batch Times

Earthworm Naturals Batch Times

Their times are measured in days.

Our times are measured in months.

Their batches are large.

Our batches are small.

Their customers buy in bags and bulk.

Our customers buy in bags.

Their customers have faith.

Our customers have PROOF.

Because every batch is tested. Every batch.

And numbered by lot. We test. We test some more. And grow.


Because there is nothing to hide here.

Correct Moisture and Proper Storage

Earthworm Naturals beds are outside, undercover, and protected from excess rain that can leach nutrients. We check moisture levels and water as needed.

Where Is The Best Place To Store Castings?

The worm bed of course. The worm castings stay right in the bed until needed. Then, we harvest on demand.

Harvesting On Demand

We estimate the amount of worm castings that are needed for a two week period. We harvest and bag them. The bags are stored in a climate-controlled area. This ensures that you receive the freshest, biologically-active worm castings. We harvest more often for your benefit.

Earthworm Naturals Moisture meter checking soil/
Earthworm Naturals Storage graphic in chalk
Earthworm Naturals Testing results
Earthworm Naturals Test Plot
Earthworm Naturals Cucumber test plot


Earthworm Naturals Protocols

We do 4 types of testing. We will list them for you. They are all important in delivering a quality product for our customers.

Test#1 - Heavy Metals and E Coli

Earthworm Naturals screens every batch of worm castings for heavy metals and e coli. This ensures that the castings you receive are safe for you and your family.

Test#2 - NPK Testing

This test is required by the state for a fertilizer license. The test also shows carbon/nitrogen ratios, elements, and electrical conductivity numbers which are useful.

Worm castings are not about the NPK numbers but we post the results for transparency.

Test#3 - Biological Assay and Profile

This test is our Report Card! The biological assay is how we determine if our inputs and processes are delivering results. We use Earthfort Lab in Oregon for this test. Earthfort Lab is the gold-standard for this type of testing.

We consult regularly with them to determine the best inputs for the results we want to achieve. This test is performed on every batch we sell. The test is not cheap...but our castings are the better for it. We also post these results for you to see.

Test#4 - The Grow Test

Here is where the rubber meets the road. You have all these numbers but will your worm castings perform? Inquiring minds would like to know!

We test worm castings potential by planting vegetables and flowers in straw bales. This takes soil out of the equation.

The test is somewhat subjective without a bunch of fancy lab equipment but we garner a great deal of information from this.

Earthworm Naturals Worm Castings

You have probably learned more about worm castings than you ever wanted to know.

But, we know how much hard work, sweat, and love goes into your garden.

There is also that feeling of pride you get when you harvest that juicy tomato, huge green pepper, or bucket of cucumbers.

Everyone wants to grow their own chemical and pesticide-free produce for their families.

We garden. We get it.

Earthworm Naturals challenges you to try our premium worm castings. You may be able to find cheaper castings but we don't think you will ever find better worm castings.

If you try Earthworm Naturals worm castings and are not absolutely delighted by the results...we want to know. Contact Iowa Worm Composting and we will make it right. Guaranteed!



Earthworm Naturals Sales Information

Earthworm Naturals is a trademarked, wholly-owned brand of Iowa Worm Composting. We produce and distribute Earthworm Naturals worm castings.

It is our product and we stand behind it. You can expect the same great, friendly service you have come to expect from Iowa Worm Composting.

We offer Earthworm Naturals worm castings in 2 sizes. (4# and 18#) There are two prices for each size. There is a "Local Pickup Price" (by appt. only) and a "Shipped To You" price.

Our batch sizes are small (less than 10 cubic yards) and generally sell out quickly.

However, we urge you to only order an amount that you can use in the current season. Worm Castings are best used as fresh as possible.

We do NOT do bulk sales. We sell by the bag only. You can order multiple bags though.

If you have worm castings left at the end of the season, we recommend taking them out of the bag and storing them. We have an easy long-term storage solution tutorial on our website.

Here is a handy reference to help you with ordering:

4# Bag = Approx. 1 gallon = 16-20 cups of castings.

18# Bag = Approx. 4.5 gallons = 75-90 cups of castings.

Try our Earthworm Naturals worm castings and plant that garden.

Enjoy that first bite of a juicy tomato that explodes with goodness.

Make your favorite pickles.

Watch those pumpkins and watermelons grow.

You. Can. Do. It.




Earthworm Naturals Worm Castings

Easy Directions For Use

Vegetable and Flower Transplants

Add 1/2 cup of castings to the bottom of the planting hole for small vegetables and flowers. Fill with soil.

Add 1 cup of castings to the bottom of the planting hole for large vegetables. Fill with soil.

This amount is generally enough for the entire growing season.

Potting Soil Indoor/Outdoor

Use a 20% ratio of worm castings to potting soil.

Example: 1 cup of castings to 1 quart of potting mix.

Example: 1 quart of castings to 1 gallon of potting mix.

We recommend a potting mix that does NOT contain slow-release chemical fertilizers.


You may side-dress plants and landscaping by working worm castings into the soil near plants.

Work the castings into the soil as shallow as possible to not disturb the roots.

Worm castings are affected by UV rays so it is necessary to cover them with some soil.



New Seedings: Incorporate 30-50 pounds of castings per 1000 square feet. Incorporating can be as easy as simply raking it into the soil.

Maintenance: Broadcast 10-20 pounds per 1000 square feet. You can use a spreader or any common broadcasting system.

Apply once per year in the Spring or Fall. Fall is our favorite time of the year to apply.

Worm Teas

Worm teas are one of our favorite uses for worm castings.

Good worm tea starts with good worm castings.

Earthworm Naturals worm castings make some great worm teas.

Worm tea allows you to stretch your castings and get the maximum benefits for your plants.


Steep or Aerate?

Should you steep or aerate your worm tea?

You can do either.

Steeping is putting the ingredients in a container and stirring occasionally. This does work.

You can even put your castings in a 5-gallon paint filter so you won't need to filter the finished tea. We recommend steeping for 72-96 hours and stirring at least once a day. More stirring is better.

Use 2 cups of worm castings for every 5 gallons of de-chlorinated water. You can de-chlorinate water by letting it sit for 24 hours or using Vitamin C powder.

Apply worm tea to your plant's root zone and/or foliage.

You can also dilute the worm tea up to 5-1 with de-chlorinated water to make it stretch further.

Aerated worm tea is made by using an air pump to inject oxygen into the water.

There is a multitude of brewer designs to make aerated worm tea. Some you can purchase and some you can make at home.

A good high volume air pump is a must and will be the most expensive purchase. However, you can put together a DIY home version brewer, with a good air pump for about $100.00.

The tea recipe is the same, but with aerated tea, you are usually brewing for 24-48 hours and get higher bacteria counts.

We devote an entire page on our website to worm compost tea. If this interests you; please check it out by clicking the link.



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