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Both worm castings and liquid fertilizers are great options for your vegetable plants or container plants. However, worm castings are an excellent, more accessible, and sustainable alternative.

Worm castings have a balanced amount of varying components beneficial to the plants and soil. You can either add it in its dry or liquid form as worm casting tea to potting soil, planting holes, or raised beds. And, for increased functionality, you can supplement with other fertilizers. This article will further compare worm castings vs. liquid fertilizer, proving why worm castings are the better option.

About Worm Castings

Worm castings are thewastes excreted by a worms' digestive system. It is simply worm poop we harvest from a worm farm that acts as a completely natural fertilizer for the soil. They are very high in nutrients and are also referred to as worm manure or vermicompost. Worm castings are natural and full of nutrients and are among the best fertilizers in use today.

Production Process

You can either buy worm castings commercially or make them at home. If you buy commercially, it is essential to check the percentage of castings present. 98 - 100% is optimal. Also, to ensure fertilized crops are safe for human consumption, the brand should ideally state on its package whether the worms are organically fed or not.

Alternatively, you can make worm castings by cultivating your own worm farm. Homemade worm castings are a simple combination of worms, compost, a worm bin or box, and a chosen method to harvest worm castings. Homemade worm castings are sometimes preferred as it gives you total control in feeding your worms. To excrete high-quality vermicompost, the worms used in castings should ideally feed on nutrient-dense and varying compost matter.

About Liquid Fertilizers

Liquid fertilizers are inorganic synthetic fertilizers produced industrially by combining needed plant compounds in varying ratios depending on desired plant growth. The combinations are nitrogen, phosphorus, and potassium, shortened to NPK. Unlike worm castings, liquid fertilizers only sell commercially and are also more expensive.

Similarities Between Worm Castings and Liquid Fertilizers

Worm castings and liquid fertilizers serve similar end goals: improve plant health, growth, and yield by providing essential nutrients.

Differences Between Worm Castings and Liquid Fertilizers

Physical Form

Firstly, as seen above, the production process is different. While worm castings are from worms, liquid fertilizers are chemicalmixtures.

Their state is also different. As its name suggests, the liquid fertilizer comes in liquid form and worm castings in granular form, a texture similar to coffee grounds and appearance like garden soil.

Absorption Rate

Worm castings are a slow-release fertilizer. That is, it releases its nutrients steadily over a long period (about two months) before the plants completely absorb them. 

It makes them ideal for container plants, hanging baskets, young seedlings, or long-term soil amendments. 

Liquid fertilizers, however, are fast-acting and contain a particular ratio of nutrients. The nutrients are in direct contact with the plants, and thus, the plants immediately absorb it in a range of one to two weeks.

This makes them more effective in fertilizing acid-loving plants or plants with high nitrogen needs like annual vegetables or citrus.

Nutrient Content

Nutrient-wise, the main difference is that worm castings contain the necessary NPK and many other nutrients and soil enhancers. Worm castings are a naturally balanced type of organic material. This implies a lot of nutrients are present but in small quantities. In addition, worm castings contain a high percentage of humus. This humic acid directly translates to the soil being able to hold moisture better, allowing better aeration and generally improving soil structure.

Worm castings contain beneficial bacteria, worm eggs, magnesium, calcium, and a neutral pH, which liquid fertilizers lack. Thus, worm castings are a great choice if we consider overall soil and plant value. However, for established plants, it may be challenging to get sufficient nutrients into the root area of the plants. Worm castings are better for use at the beginning of the growing season on seed starting soil, transplants, planting holes, or smaller-sized gardens.

Notwithstanding, you can mix worm castings with acid amendments or other additives to fertilize vegetable plants or citrus.

Liquid fertilizers only offer specific nutrients and do little in soil quality improvement. It also only stays a short while before exhaustion, with a maximum of a few weeks. This short time requires frequent reapplications. It is also at risk ofevaporating.

Application and Use

Earthworm castings contain a lot of organic matter and beneficial microbes that are good for soil structure and plant growth. This attribute, combined with the worm castings' slow release of nutrients into the soil, allows the plants to slowly absorb and build strength without burning the roots or causing unwanted foliage growth.

Worm castings are also not hot, allowing you to directly apply them to vegetables, hanging baskets, potted plants, or perennials. Unlike chemical fertilizers, worm castings do not hurt plants. No matter how much you add, there is no such thing as too many worm castings. For transplanting vegetable plants or indoor flowers, you can add a quarter cup of worm castings in each planting hole. You can also mix worm castings with potting soil to give plants a good start.

You can also make worm castings into liquid organic fertilizer called worm casting tea or worm tea. This adds versatility to its use and application. To achieve this, you mix dry worm castings with water in a ratio of a quarter cup to one gallon. Vigorously shake and leave to sit overnight or a day before use. However, unlike its coffee ground form, the liquid does not remain usable for extended periods, so only mix needed amounts.

While applying liquid fertilizer, spraying is the most common method as it is more consistent. You can spray the liquid directly on plants, gardens, or potting soil. It is good to use when fast results are required.


When comparing worm castings vs. liquid fertilizers, we prefer worm castings. This organic fertilizer has a range of functionality, and its value puts it a step above liquid fertilizers. You can use it when planting perennials, hanging baskets, flowers, potted plants, and so much more. You can also mix worm castings with fertilizers of your choice for your annual plants or vegetable garden to boost their overall health and growth.

Grow Bigger Plants with Simple Grow

Do you wish your plants would grow bigger? Was your garden less than it should've been last year?

If you're tired of growing puny vegetables and fruits, it's time for an upgrade...Simple Grow Worm Castings!

What are worm castings? Another term for worm manure. Why would you want to use it in your garden, raised beds, and house plants? Because it makes them grow bigger, faster and healthier...with no chemicals!

How do worm castings do this? It's like giving your plants a powerful multivitamin with everything they need to grow. Trace minerals, nutrients, and most importantly...worm castings are chock full of beneficial microbes. Why does that make a difference?

In recent years, we've learned the importance of gut bacteria for humans and know that it impacts so many different parts of our health. The same thing applies with worms. Gut bacteria from the worm's digestive tract gets into the soil from the worm castings and promotes plant health. Plants have a symbiotic relationship with the microbes from the worm's digestive tract. Plants respond to it and grow really big...really fast!

If you've never tried worm castings before, you owe it to yourself to give them a try. Instead of using traditional chemical fertilizers from the big box store, why not try fresh, certified organic worm castings this year? You'll be able to grow bigger, healthier plants that you actually can feel good about eating. 

Take advantage of our special bundle sale on 25lb bags today!


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