Compost tea: the stinky secret and why it is so good for your plants



by  Emily Cates


Part 2 of 2

Last time we touched on how compost tea is made and its purported benefits for plants. Now, let’s discuss what materials we could use to make it. Prime candidates include finished compost, livestock (not pet) manure, worm castings, seaweed, coffee, comfrey, nettles, horsetail, garlic, or even weeds. Feel free to experiment with single-variety or mixed brews. Many sources recommend aerating the tea as it brews – though some folks don’t and still get good results. The kind of bubbler that’s used in fish tanks will work. (Try it with recipes of all the different materials mentioned in this article.) Let’s look at these materials one at a time and see what they are claimed to be especially good for. For helpful, in-depth information regarding soil microbiology- which is the system on which benefits of compost tea are based upon- follow this link:

A tea made from finished compost provides nutrients and beneficial microorganisms that promote health and growth. Why water with plain water when you can add a spot of tea? Brewing compost tea is thought to make the nutrients easier to absorb, especially when aerated. Also, when working with compost or similar substances, it might be helpful to place the contents into an old pillowcase or something similar to make a “tea bag.” That way it’s much easier to handle. For more info on compost tea, check out this link:

As long as the manure used is completely Compost teafinished and sourced from herbivorous animals, manure tea is a viable option to the adventurous gardener. Similar to compost tea, it too provides a web of beneficial microbes and may help plants increase their hardiness and resistance to pests. There is debate on the safety of un-aerated manure teas; to be on the safe side, it may be wise to use a bubbler. Also, when applying manure tea to plants that will be eaten, it is advised – just as when applying manure to a garden – to wait 90 days to harvest above-ground plant parts, 120 for below-ground parts. Here is a link for info about making and using manure tea:

If you practice vermicomposting, then you no doubt have a supply of worm castings to make tea with. If you’ve never tried composting with worms, you should! (More on that in a future article.) Every gardener I have talked with over the years has a special place in his or her heart for earthworms. Their rich castings, a.k.a. “poops” are a known benefit to soils and are a pillar on which healthy soils stand. One could reason that something this good for healthy soils could be good for healthy plants. Many sources recommend adding molasses when making worm casting tea. Here’s a link:

Loaded with minerals and plant growth-promoting and regulating substances, seaweed has been used for ages as a secret to great gardens. In addition to being a valuable soil amendment, it, unsurprisingly, makes a good tea. Just make sure yours is sourced from un-polluted areas. I found this link entertaining and helpful:

While we’re talking about tea, we might as well mention coffee. Before you toss the grounds into the compost pile, why not brew up some coffee-tea? Some folks swear their roses, citrus, blueberries, and other acid-loving plants perk up from a dose of it. Here’s a link about using coffee grounds in the garden: http://organicgardening.

Comfrey: This herb is a blessing or a curse, depending on where you plant it. The bad news about comfrey is that it can be invasive. It needs to be controlled with a regular harvest without going to seed. Disturb the roots and it will spread. If you plant it in an area where you can mow it and the roots and flowers are kept far away from the compost pile, you should be okay. Think orchards. Also, comfrey may be grown in large containers. The good news about comfrey is that it is regarded as practically a miracle plant by gardeners. Its deep roots bring up nitrogen, phosphorus, potassium, calcium, and many other nutrients from the soil. It is also a potent activator for soil microbes. It grows into a fairly large plant, so it is quick and easy to harvest a lot of it. I just stuff it into a 5-gallon pail halfway or so, fill with water, and cover. I try to stir it every day for about three weeks, and then it’s ready to dilute at least 1:10 as a liquid fertilizer. For more info, follow this link:

Nettles: You’re going to need gloves for this one. Stinging nettles, known for their stinging properties when brushed against, are also known to be loaded with minerals and nutrients for man, beast, and flora. Nettles are said to even strengthen neighboring plants as they grow, and to increase yields. Whilst gathering the early spring nettles for cooking, I make it a point to gather as many as possible for the compost tea bucket, following the same method as for comfrey. Here’s a helpful video:

Horsetail: This herb is abundant in silica and is oftentimes used in tea on fruit trees to strengthen them and help with diseases that are worse in wet weather.

Garlic: Garlic and other alliums are abundant in sulfur compounds, which are known to be helpful against fungal diseases in plants.

Weeds: Plants with long roots such as burdock, curly dock, and dandelion are believed to confer strength, vitality, and resistance to stress. Have you ever tried to pull them up? Those thick, strong taproots bring up nutrients from deep down, so you know they are loaded with minerals. It is also said that vigorous, hard-to-eradicate weeds such as quack grass or knotweed infuse the tea with their heartiness. Others, such as mint, tansy, and chamomile, have aromatic qualities that may help repel pests. Really, just about any weed that doesn’t cause you an allergic reaction can be brewed into compost tea. What better way to gain retribution for noxious invaders in your garden?


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