COMPOST as Fertilizer and Soil Amendment



There are many different kinds of compost – the bagged kind you get at home improvement stores, the homemade kind (my favorite), composted manure and municipal compost – you know, processed city waste (my least favorite).

To create compost effectively, use both brown (carbon-rich) and “green” (nitrogen-rich) ingredients. Leaves, paper, straw and other dead materials work well to provide carbon; and manure, vegetables, fruit and urine supply nitrogen.

Why might compost be good for the garden?

Compost helps regulate soil pH. It also adds organic matter, supports microorganisms, improves drainage, promotes air flow, and helps microorganisms release nutrients already existing in the soil.

Where do I find “quality” compost?

A good quality compost will be made up of a variety of ingredients that provide a variety of nutrients. If you make your own, you can control what goes into it.

I see ads on for free and low cost compost. Sometimes the poster reveals what the compost is made from. Go ahead and ask what went into the mix.

If you buy compost at the store, check the ingredients list to see if you have more than two or three materials – the more the better. It’s common to see two or more of these items: alfalfa meal, kelp meal, bat guano, dehydrated poultry manure, feather meal, composted rice hulls, forest products, composted dairy manure, peat, ash, sand, and native topsoil.What is in compost

Also check for vague terms in compost such as “compost” because compost can be created using human sewage sludge, otherwise known as biosolids. It also goes by many other misleading brand names.

Which plants may benefit from compost?

All edible plants benefit from soil amended with compost. Soil bacteria, fungi and other microorganisms benefit from compost. Plants thrive in a medium that lets air in and water through. Nutrients are more effectively “mineralized” and made available to plants in a soil that contains organic matter.

How to Apply Compost

How much compost to add depends on your goals. Are you starting a new bed from scratch or maintaining an existing garden?

New Garden Bed

For new garden, you can take a few different approaches.
  1. You can combine topsoil and compost at the same ratio, 50/50, and call it a day.
  2. Or you can use a mix made famous by Mel Bartholemew, creator of the Square Foot Gardening technique. “Mel’s Mix” consists of 1/3 vermiculite, 1/3 peat moss and 1/3 compost.
  3. Another option is to try “Lasagna Gardening”. This involves layering materials such as dried leaves and grass so they will decompose over time. Newspaper goes in between the layers. Cover with an agricultural cloth that lets in water and breathes. You will need to wait several months to plant in a lasagna garden, maybe even a year so this technique is for patient people. Lasagna beds tend to warm up faster in the spring.
Maintain an Existing Bed
  1. Fall: To keep the nutrients and organic matter at a beneficial level, in the fall add 3 inches of compost to the top and let it naturally integrate over winter.
  2. Spring: If you missed your opportunity to amend in the fall or prefer to condition your soil in the spring, add the three inch layer but work it into the top layer of soil before planting.
  3. Homemade Compost Recipe

At school, when students ask me how to compost, I scoop up a handful of rich soil and explain that kitchen scraps, leaves and more can be mixed together to create a “special material” that plants, worms and tiny creatures love. Several times a year I put on an interactive and exciting demonstration that shows how humus is made in nature. Then the students learn how people make compost. The process is simplified and it’s then just a matter of time before some of the kids rush to my side with news that they are composting at home.

The best way to learn how to compost is to do it. Here’s how:

Choose a composting technique that works best for your location and lifestyle.

Pick a location that speeds up the process or gives you a place to park your scraps for the long-term. If you live in the country, a compost heap makes sense. You’ve got room to tuck the pile away around a corner or anywhere you like on your property. If you live in suburbia like me, a tumbler or compost bin keeps the animals away and prevents issues with neighbors. If you don’t have the room or are not allowed to have a composter, you do have options.

Although compost will cook in the shade, and even during the winter months, the best location to speed things up is in full sun. If you don’t mind waiting a year or so to harvest your compost, you can build a simple pile using fencing or pallets.

Compost everything you can and mix things up.

Combine carbon-centric materials and those that are nitrogen-rich. They’ll react together to create heat and initiate microbial activity which breaks down the stuff into soil amendment.Never use these in compost

Carbon materials, referred to as browns” include leaves, straw, coffee filters, paper and most dried plant matter. Browns are usually brown in color but not always. Nitrogen-rich greens include vegetable scraps, freshly cut grass, melon rinds, coffee grounds, alfalfa pellets and manure.

Never use meat, dairy, plastics, glass or human, dog, cat or pig feces in homemade compost.

Adding different things to compost

Chop Up Materials

You don’t have to chop up the materials. But to make the process go faster, chopping or shredding exposes more of the material to air, water and microorganisms. You can throw an entire watermelon into the compost pile but it will take much longer to create compost.It’s especially important to break up corn cobs and egg shells.

I also add any leftover cooking water to my compost.

Chop up larger items for composting

Create a Good Compost Mix

Add the materials to your pile, bin or tumbler. Mix up the brown and green materials. If you are adding lots of fresh grass clippings, work in lots more carbon-rich materials like dried leaves. The ratio I use is 40% green to 60% brown – always a bit more brown. Water the contents well and keep moist like a wrung out sponge. When you add greens to the pile, cover them with brown materials to keep critters away.

Turn and Accelerate

It’s optional to turn the pile but things will go faster if you do. Mix the contents of your pile each week to spread out microbial activity and ensure all the materials get a dose of what’s good for them. To rev it up even more you can add materials that tend to increase the heat in the pile: alfalfa, fish waste, manure and garden soil.

Compost Completion

Turn the compost at least weekly if you want a finished product in months instead of years. I’ve made compost in a tumbler in just 2 months using vegetables scraps, paper, dried leaves and alfalfa pellets as an activator. Conditions were just right. But the weather and materials don’t always cooperate. The time it takes for compost to finish varies. Just makes sure it is actually finished before you use it.

Finished compost is dark brown and crumbly. The contents are no longer recognizable. It can take weeks or years to get to the finished stage depending on conditions and materials in the pile.Checking compost to see if finished

Unfinished compost still has large pieces of material in it that have not broken down. It may not smell fresh yet. Incomplete compost is detrimental to the garden because it will tie up nutrients during decomposition. Microorganisms will steal nutrients away from the soil to break down what’s left. Unfinished compost containing manures could even become toxic because of high amounts of ammonium.

More Than One Composting System

Some folks have one huge compost pile that they continuously add materials to. Others do their business using bins and tumblers.

I have two composters. Once one composter is full, I start adding materials to the other bin. By letting one “cook” without introducing more materials, I get finished compost faster.

  1. Compost Tea Recipe

Once you have a good quality compost on your hands, you can use it to make a tea for your plants. Add a few cups of compost to an old sock. Unless you’re superhuman, you must have a stray sock somewhere around the house. I like to use cotton socks that can be composted when I’m done with them. Some folks use nylon and reuse the sock over and over.

Once your sock is full of compost, (not too tightly packed or it could bust a hole and make a mess), close it up with a knot or twist tie and plop it into a big bucket of water or your watering can. Let it sit for 1-3 days, stirring well once a day. Use the compost tea to water your plants. Moisten the soil first before using compost tea to ensure nutrients travel freely. (You’re going to get sick of me suggesting that you water first before you fertilize – I apologize in advance.)

Molasses anyone?

You have the option of adding molasses to the tea mixture at the beginning. Some believe it increases microbial activity. I have used molasses several times and can’t isolate whether it made a huge difference or not. If you have leftover molasses and would like to recycle it, or feel like experimenting, go ahead and add 1 tablespoon of unsulfured molasses for every gallon of water used. It does not need to be an exact measurement.

Manure Tea

I don’t usually add fresh manure to my compost pile so I don’t have to worry about it not being composted enough or aged to kill pathogens. If you do use manures, ensure they are well composted. If you still smell the manure, it’s not ready. Manure tea should be applied well before crops will be harvested.

Aerating Compost Teas

Lots of information exists about the potential benefits of aerating compost teas. Forcing air into the solution is supposed to increase microbial activity. You can do this with a fish tank pump, air stone or special aeration gadget. I don’t do this because I’m lazy and from the research I’ve read, the supposed benefits are not worth the time in my garden.

Fermenting Compost Teas

Yes, I’ve done this and my poor neighbors know I’ve done this. The stench carries and it takes a while to clear your nose when you’re fermenting compost teas. I am not a fan.

Fermenting has the potential of not only ticking off the neighbors, but it can create bad bacteria that are unsafe for us to breathe or to come in contact with. It also has the potential of throwing the soil off balance. Still, there are folks that ferment with fervor and love what it does for the garden.

I’ve tried fermenting in one bucket and using two buckets. To use two buckets, put a hole in one and sit it on top of the other. Add your materials in the top bucket and let the goop seep through to the second bucket.

There are plenty of references on the Internet that will explain how to ferment teas. I am not an expert and will defer to the brave fellows and ladies that do it well.

Compost Quick Tips

  • To make compost that does not smell or attract flies, (or to stop a pile from stinking), add more brown materials, e.g., dried leaves, cardboard and dead matter.
  • Some materials speed up the composting process because they create heat that stimulates microbial activity. To rev up your compost pile, try adding natural compost accelerators such as alfalfa pellets, comfrey/borage, garden soil, worm castings or human pee.
  • Many references recommend that you only need 5-10% compost in your soil to take advantage of its benefits.
  • Don’t let your compost dry out. If it does, water it well, mix it up and vow to keep it moist for faster results – only as moist as a wrung out sponge.