Compost Tea – What, Why and How?
If you’ve been following our Organic Garden Diary series (if you’re not you really should!), you have read about how well our garden is doing this year. In the 10 years or so that we have had our garden, we have never had such lush, abundant and healthy growth from all of our plants. The only thing that we’ve changed this year……2x weekly doses of compost tea. Needless to say, we’ve seen the results with our own eyes and we are believers…….you can buy it commercially from many sources – read below – but we were going through so much that for Mother’s Day, my husband built me a 35 gallon compost tea brewer (I know you’re jealous!) and we’ve started brewing our own!
So, let’s start from the top: What is compost tea? What’s the difference between compost and compost tea? Why is compost tea good for my garden? How does one get compost tea?
Most, if not all, gardeners are familiar with compost – that decomposed organic matter like leaves, grass clipping and fruit and veggie scraps from the kitchen that we so love to add to the soil in our garden. We’ve been taught that adding compost to our soil every year enriches it with nutrients, adds and feeds the diverse bacterial and insect life of our soil and improves its ability to retain moisture thereby making our garden plants happy and healthy. Many of us, my family included, have even taken the step of making our own compost by using the discarded or unused organic table and yard scraps – leaves, grass clippings, coffee grounds, veggie and fruit peels, etc and adding them to our compost bin – this one is similar to ours – out behind the garage and turning the pile occasionally to facilitate the decomposition process. In the late winter/early spring we gleefully fill our wheelbarrow fulls of this black gold to work into our garden soil. What’s not to like about that? Reduce waste, conserve and be prudent stewards of our planet and at the same time provide excellent nutrients for our garden. I get that…..but compost tea????
What is Compost Tea?
Simply stated, compost tea is a water-based solution that has been amended by adding compost to it, and in some cases other nutrients, and letting it “brew” or steep in water (not over any heat source) thereby enabling all the wonderful microorganisms in the compost to leech into the liquid and infusing the water with all the goodness any garden can desire! Think the tea you make in a teapot where the tea in the tea bag is replaced with compost. The logic is of course that if the compost added to the soil is beneficial, then so is the water that has been infused with the same beneficial microorganisms .
Basically, there are two types of compost tea: 1) Passive or 2) Actively Aerated Compost Tea (AACT). Both provide benefits to your soil and “passive” tea is very simple and inexpensive to make, but the research has shown that AACT provides an added turboboost to the solution that is filled with the beneficial microorganisms that are so beneficial to your soil and plants.
Passive tea is made by basically dumping a load of compost into a bucket of water, stirring it about on occasion to release the microbes from the compost into the water and letting it sit for a short time to enable the microbes to work their way throughout the solution.
Actively Aerated Compost Tea (AACT) is a “tea” that is made by adding compost to a solution of water, but in this case, we add nutrients – e.g., black-strap molasses, liquid kelp, hydrolyzed fish, etc – and oxygen to the water to feed the beneficial microorganisms with the goal of enabling them to reproduce, multiply aggressively and supercharge our “tea”. There has been extensive research on the subject of compost tea and it’s benefits and the science seems very clear that AACT provides far more beneficial organisms in your tea than does the passive alternative. This video shows the active aeration of our tea.
What’s the difference between compost and compost tea?
We use both compost and compost tea in our garden, as they both have their place. Your soil structure will benefit from actual compost as it helps bind the soil particle aggregates. Compost-rich soil is more aerated with air tunnels that enable your soil to retain air, moisture and nutrients. Actual compost helps amend sandy soils to retain more moisture and nutrients and helps loosen the clay particles in heavily clay soil to improve aeration. Both compost and compost tea add and feed the important microbe and insect life in your soil. This is an important observation: The more alive your soil is, the healthier it is. Think of your old growth forests and all the life teeming on the forest floor that feeds on the decaying leaves and other organic matter. That’s your goal for your garden soil.
Where compost tea and compost differ is in a couple ways: Because the tea is in a liquid form, it’s easier to distribute on a regular basis, especially on a lawn or similar area. As a foliar application, compost tea distributes these helpful microbes on the leaf and stem surface, which can then crowd out less beneficial pathogens or directly provide nutrition. It’s important to note that the jury is still out on whether foliar applications actually reduce plant disease, but there is no data that is actually harmful, so I’ll continue to use it foliar-ly. Finally, and possibly most importantly, the actual brewing process feeds and energizes the beneficial microbes in the compost. So, when you do apply them to soil, they’re in NASCAR mode.
Why is compost tea good for my garden?
The production of any garden is only as good as the health of the soil from which it grows. The real benefit of compost tea is that while is does provide some plant nutrients inherent in the compost to the soil, more importantly, it introduces a wealth of the kind of beneficial microorganisms to your soil that foster the very decomposition process and feeding cycle that provides more usable and sustainable nutrients for your plants. It’s quite possible that your soil is filled with organic matter and nutrients that are not in a form most beneficial for your plant to use. The microorganisms in compost tea provide the basis by which organic matter and chemical nutrients are broken down into usable plant food and an efficient and effective soil life cycle. Making compost tea a great tool to replenish barren soil or even just introduce a wider variety of bacteria, fungi and protozoa that are the basic foundation upon which organic decomposition takes place. This was EXACTLY the case with our garden soil. The soil analysis provided by our friends at Progressive Gardens that we referenced here showed us that we had adequate organic matter in the soil and we fertilized regularly but our soil was “constipated”! The organic matter was not in a form usable to the plant as nutrients. There is also a school of thought that drenching the foliage of your plants with tea also benefits the plants by coating the leaves with beneficial organisms thereby “crowding out” more harmful elements making your garden less susceptible to disease. While there are many believers, the science is still inconclusive on these claims, but as it relates to benefits to the soil, the science is clear and compelling. As I mentioned in the opening, we’ve been actively working an organic veggie garden for over 10 years – 5 raised beds, approx 130 square feet – and we began adding 25 gallons of compost tea to the soil AND foliage twice weekly and our plants have never been more lush, healthy and productive. There is a wealth of information on composting and compost tea, here are some:
How does one get compost tea?
Compost tea is becoming more available from commercial sources with each passing day. Here are some options:
Brew Your Own!
We use a large amount of tea on our garden. You can’t apply too much tea to your garden – unless of course – the soil is oversaturated to begin – but under normal conditions your can’t “overtea” your garden. We use approximately 50 gallons a week on our 130 square foot garden – that works out to about 3/8 a gallon per square foot. Do your own calculations for the size of your garden to determine your needs. It became clear that because we use such a large amount, we would be better served by brewing our own tea. Keep in mind that the quality of your compost tea is only as good as the compost from which it is made. Bad Compost = Bad Tea. However, if you don’t want to or can’t make your own compost there are many, many “how-to’s”, commercial sources of compost and compost tea brewers for sale – all sizes, shapes and costs.
Here are a few I found on Amazon:
Please note, I have not tested any of these brewers myself, so this does not represent any kind of endorsement for any of them, but as you can see, the elements are all very similar and simple…..a vessel to contain the solution, air pump and tubing to introduce oxygen to the solution and nutrients to feed the microorganisms. As you can see, some of the larger brewers are quite expensive. Rather than make such a large expenditure I asked my husband to make one for Mother’s Day! Now that is a story for another post….stay tuned for how to make your very own compost tea brewer!
It can easily be purchased online from a variety of suppliers
A quick check on Amazon yields a variety of types, sizes and prices:
Tea and Tea Bags:
- Ultimate Compost Tea – Gallon
- Ultimate Compost Tea – Quart
- Organic Compost Tea (2 qt)
- Bu’s Brew Biodynamic Compost Tea Bags
In most areas, you can find a garden store that brews their own tea and offers it for sale to consumers.
Our local organic garden store, Progressive Gardens, sells high quality tea for $1.25 a gallon or so. Progressive Gardens also sells a Vortex Brewer. Check your local garden store for their offering.
We will be back soon with detailed instructions on how my husband made our 30 gallon Compost Tea brewer and the recipe we use to brew our twice weekly batches of tea. I have to tell you, Terry gave many field trips to the Compost Tea Brewer during our recent Graduation party!
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Until next time,
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