If you’ve had your worm bin up and
running for a couple of months, you’ve probably accumulated a decent amount of
rich, dark byproducts of worm digestion, known as worm castings. These castings
are one of the best organic soil enrichment tools available to gardeners. When
they are mixed into garden soil (5% to 25% casings to soil ratio), there is a
dramatic improvement in soil potency, aeration, water retention, and nutrient
availability.
Worm tea is made by steeping worm
castings in water. This encourages microbial activity by creating a
nutrient-rich, microbe-packed liquid that can be sprayed on leaves or applied
directly to soil. Not only is it incredibly easy to develop, but it is also
incredibly effective and a great way to stretch your supply of worm castings.
Simple Worm Tea Recipe
To make worm tea, fill one cup with worm
castings and place them into a 4” x 6” muslin cotton bag, tying it shut. In a
sense, this bag acts like a giant tea bag. The solids in it are kept contained
while the beneficial microbes and nutrients are allowed to steep into the
water. Next, place the filled bag into a five-gallon bucket of dechlorinated
water or non-chlorinated water, or the chlorine will kill the very microbes
you’re trying to cultivate in your “tea”. Using tap water is fine, as long as
you leave it out for 24–48 hours before brewing to allow the chlorine to
dissipate.
The next step is to add 1/4 cup of
unsulphured blackstrap molasses to the bucket, which will act as a food source
for the beneficial microbes, allowing the castings to multiply rapidly. Make
sure not to use sulphured molasses, as it contains preservatives that can harm
microbes, rather than help them.
Once all of the ingredients have been
added to the bucket, stir the mixture thoroughly until the water darkens. Now
you’ll need an air stone connected to a small aquarium pump. Place the air
stone at the bottom of the bucket and let it bubble continuously for 24 to 72
hours. This aeration step creates an oxygen-rich environment that favors
aerobic microbes while preventing anaerobic bacteria from growing, and is thus
vital to the process. When the surface of the mixture is foamy and bubbling,
your worm tea is ready to use.
Using Worm Tea To Help Fertilize Plants
Worm tea is an incredibly versatile
liquid fertilizer. It can be used to either drench the soil to feed plants
directly at the root, or as a spray that applies the microbes and nutrients
directly to leaves. Gardeners who utilize worm tea consistently confirm that
regular application helps increase plant growth, yield, and resistance to pests
and disease.
When worm tea is used in the form of
foliar spray, it should be strained through cheesecloth or a fine mesh bag to
prevent clogging the spray bottle. It is best to apply it in the early morning
or late evening to avoid sunburn on leaves and to allow ample time for the
microbes to colonize the leaf surface before the sun dries them out.
In terms of frequency, worm tea should be
applied once every week or two during the growing season for best results.
However, worm tea is gentle and won’t burn plants, so you can use it as often
as you believe it's needed, without much of a negative consequence. The only
caveat is that it should be used within a few hours of finishing the brewing
process, as the microbial activity starts to decline after the first day or so,
even if stored in a sealed container. By using it soon after preparation, you maximize
the worm tea’s efficiency.
Worm Tea Benefits
There are numerous benefits of using worm
tea. First, it provides plants with water-soluble nutrients that promote rapid
plant growth, healthy green leaves, and strong roots. Moreover, worm tea
introduces billions of beneficial microbes into your garden.
These microbes help break down organic
matter into nutrients plants require, enhance soil structure, and ward off
harmful pathogens as a large microbial population fights off unwanted microbes,
and helps to suppress diseases like root rot and powdery mildew. This helps the
soil resist being compacted and to better retain moisture.
Another benefit is the potential for
natural pest control. Some gardeners find that plants treated regularly with
worm tea are less attractive to pests like aphids and spider mites, though the
exact reasons are not fully understood at this time. Plants treated with
worm-tea, however, do consistently exhibit a stronger immune system and better
resist pests.
Why You Should Use Worm Tea
Worm tea is an easy-to-make,
cost-effective, and environmentally friendly liquid fertilizer that benefits
nearly every aspect of plant and soil health. With a little blackstrap
molasses, some dechlorinated water, and a bit of aeration, you can turn a handful
of worm castings into a microbial super-tool, which will help take your
vermicomposting and gardening efforts to a new level.
