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BEACON Senior News - Western Colorado

Boost your garden with compost tea

Aug 02, 2022 10:10AM ● By Bryan Reed

As we enter the home stretch of the growing season, giving your plants a boost of nutrients can really help round out your crop production, resulting in more nutritious produce for you to eat.

Give leafy vegetables such as lettuce, culinary herbs, kale and spinach a nitrogen boost by adding feather meal, blood meal or neem seed meal to the soil. Provide tomatoes, cucumbers, melons, peppers and other flowering fruits with extra phosphorous using bat guano, fish meal, or steamed or liquid bone meal. To promote strong plants and nutrient-dense produce, add some kelp or azomite into the mix.

Liquid is better

Traditionally, we add fertilizers to the soil surface and hope for rain or irrigation water to flush it down into the soil. But granular fertilizer takes three to four months to break down, which won’t help this time of year. 

Use liquid fertilizers at this point in the season. Liquid fertilizers are fast-acting, penetrating the soil and reaching plant roots in as little as 45 minutes. You can purchase them from local garden stores, or you can make your own by adding nutrients to a one- or two-gallon bucket and letting it soak in irrigation water. Let it sit for one to three days, stirring a couple times each day. Then shower the plants and soil using a spray tank or hand sprayer.

Liquid fertilizers can also be applied directly to plant leaves, where essential nutrients can be absorbed through the stomata (small pores on the leaves). Called foliar feeding, this technique is often used by commercial growers to push production and guarantee the most economic gain from fertilizing. Foliar spraying can be done in the evening or early morning. During the day, the stomata are closed tight and won’t accept the nutrients.

Quality vermicompost (worm compost) is the best product to use on your garden.



Recipe for compost tea

The best type of liquid fertilizer is a batch of homemade compost tea. That’s because compost contains plant nutrients, trace minerals and beneficial microbiology that aid in plant growth. 

Quality vermicompost (worm compost) is the best product to use on your gardens by far. Studies using vermicompost tea have shown that it wards off insects and plant diseases while nutrients are absorbed into plant leaves and roots. 

If you use a manure-based compost, make sure that high temperatures have killed off any pathogens before applying it to plant leaves. When in doubt, stick with applying it to the soil.



To make compost tea: 

1. Fill a 5-gallon bucket with irrigation water. Don’t use domestic water, as it contains chloromine, which kills beneficial bacteria. 

2. Air is critical to keeping the microbes alive and multiplying. Use a small fish tank pump with a diffuser at the end of the rubber tubing. I’ve also used a fish tank pump connected to 1/4-inch soaker hose tubing for complete coverage at the bottom of the bucket.

3. Use 1 quart of excellent vermicompost in a mesh bag secured to the side of the bucket with a clothespin. Nylon paint sprayer bags or a cut-up cotton T-shirt work well for this purpose. 

4. Add 1-3 tablespoons of molasses as a catalyst to feed the microbes. Biodynamic growers also like to add native plants (and weeds) to the bucket to extract nutrients, minerals and plant growth hormones.

5. Run the air pump for 24 to 48 hours and the compost will liquefy as the microbes double in population each hour. There’s no smell and a nice foam on the surface tells you it’s a great batch of compost tea.

6. The microbe population peaks at around 24 hours and stay viable up to 48 hours, providing a nice window of opportunity to apply the tea. Dilute it with irrigation water at a ratio of three parts water to one part tea for most crops, and two parts water to one part tea for stressed plants. 

7. Add 1/4 teaspoon of liquid dish soap (not anti-bacterial) or liquid castile soap per gallon of tea, as it helps it cling to the leaf surface longer for better absorption.

Apply the tea in the evening when the stomata are open. This allows for the microbes to nestle into the leaf tissues overnight without being harmed by UV rays. Be sure to coat the underside of the leaves and spray the plants until the tea drips off the plant—the excess is great for the soil. 

A five-gallon bucket of tea can make up to 20-25 gallons of applicable compost tea. Even a one- gallon batch can be stretched a long way for a small garden. Use it to spray trees, shrubs and houseplants, too! Dilute any leftover tea with water and apply it to the soil all around the property.

Compost tea is economical and effective, so it can be applied every two to three weeks during the growing season.

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Read more gardening tips here.

Watch Bryan brew a batch of nutritious compost tea.