What is it?

Aug 5

Compost, Vermicast, Extract, Teas, Bug-in-a-Jug, Slurries? Are you confused yet? It can be tricky to talk about these different amendments because there isn’t always a clear definition. Here’s a quick guide to help you understand how we define these amendments and their applications.

The Solid Amendments

Have you ever applied compost as a fertilizer? For a lot of us, that is exactly how we use compost. It’s not that our soil is deficient in these nutrients, rather they are in a form that’s unavailable to the plant. If we have the complete soil food web in our soil, our microbes can provide plants with the nutrients they need. So why not add the microbes instead? When we use compost to introduce microbes to our soil rather than as a fertilizer, we don’t have to use nearly as much compost—if we use quality compost, of course. There are plenty of types of compost so here’s a quick breakdown:

1. Compost

Several Methods: Thermophilic, Johnson-Su, Static, Aerated static, Bokashi, etc. regardless of the method, a quality compost will be biologically complete with the right balance of bacteria and fungi for the desired crop.

2. Vermicompost

Compost made by worms. Vermicompost contains additional compounds that benefit the plant as well as beneficial microbes. Because worms add their own unique microbes to the compost through their digestive system, vermicompost can contain different microbes from compost. Using a combination of compost and vermicompost can add more diversity to the system.

3. Vermicast

Often used interchangeably with vermicompost. Basically, it’s vermicompost that has been broken down even further, or worm poop, in simple terms.

4. Biochar

Simply put this is charred wood but notice the “Bio” part? This means there should be microbes added to the charred wood. To make biochar, a liquid form of compost or vermicompost is sprayed on the char to create Biochar. Because of all those nooks and crannies, bio char has a lot of surface area. It can hold a lot of water and provides habitat for soil microbes. It may even have applications in dealing with high levels of heavy metals in the soil.

The Liquid Amendments

Applying compost in a liquid form allows us to apply small amounts of compost. Check out this short video where Nicole Master’s explains the different liquid amendments. The benefit of using a quality compost in liquid form means we can use small amounts, <5 pounds per acre. Is that a typo? No, I meant less than 5 pounds. If we use quality compost as a microbial inoculant, we need just enough to jump start the system. Here are some of the ways we can apply compost in liquid form:

1. Extract

Can be made from vermicompost, vermicast, or compost. The solid compost of choice is placed in a compost tea bag or brewer and aerated in water to extract the microbes from the compost. No food is added. Because of this extracts are user friendly as long as you’re using good quality compost.

Remember, it’s important to test your compost. Drop us a line to learn what’s living in your compost or liquid amendment.

Application:

· Applied directly to the soil surface

· Usually applied during the dormant season

· Extracts can also be applied by soaking seeds prior to planting

· More shelf stable than teas

2. Tea

Compost tea is like extract, but the goal is to increase the microbial numbers through brewing. To do this we add foods and aerate (brew) for 24 hours. Teas are tricky because the microbes are growing rapidly depending on temperatures, compost quality, and quantity of foods added. It can be easy to mess up by adding too much food or fluctuating temperatures. Too much food = rapid increase in microbes = anerobic conditions = pathogens. Yikes. If you’re going to use teas you need to either:

1. Send it off for microscope analysis

2. Have a microscope handy and know what to look for

Application:

· Foliar treatment of plants. Since microbes are rapidly growing, they’re already creating glues which allow them to stick to plant surfaces.

· Useful for protection from pests and diseases.

· May be important to avoid UV light as this may kill microbes

· Application in the morning or evening or on cloudy days may be more ideal

· Should be used within 4 hours of brewing completion

· Not shelf stable

3. Slurries

Compost solid is mixed with water. No brewing or extraction.

Application:

· Any time of the year

· Can add minerals or even seeds to the mixture

· Kept in an aerated tank during application

Purpose: Adds diverse microbes, plus some organic matter, the “home” for the microbes, and other compounds in the compost.

4. Worm Leachate

Be very careful. There’s folks that swear by using the liquid that is at the bottom of your worm bin, some bins have a spigot for that purpose. My warning for you: proceed with caution and get it tested! The liquids at the bottom of a worm bin are often from overwatering or decomposing vegetable scraps. Sometimes it contains pathogens which is why there’s such a mix of reviews and data on whether it’s beneficial or not. In a worm bin that’s well-managed, there shouldn’t be any liquid in the bottom.

Our suggestion: If you want to use a liquid from your worms, make an extract from the vermicompost instead.

5. Bug-in-a-Jug

Ok, this isn’t the general name, but it is a term some folks use to describe an off-the-shelf microbial inoculant. The label may say something like “contains millions of bacteria”. Sounds great, right? Well, the jury is still out on that one. The large quantities of microbes may sound good, but the number of species is very low. Are we potentially causing issues by adding large quantities of a single microbe? Why not add the entire soil food web from a compost instead?

Application

· When you have a specific microbial problem, this might be tool to investigate.

Whether you’re using compost of a liquid amendment, it’s important to test it. Microscope analysis is a great way to see whether we have the microbes we need or if there are potential disease-causing organisms present. Drop us a line if you’re interested in a test or learning how to look for yourself.