Don’t Throw Used Tea Leaves! The Magic of Adding Tea Leaves to Compost

Used tea leaves are a built-in part of the tea-drinking experience. Whether you’re someone who prefers loose leaf or tea bags, there’s always at least a few grams of tea leaves left after steeping – which you unfortunately can’t reuse (unless you want a really diluted cup of tea). So, what happens to these tea leaves? For most people, they end up in the trash.

Considering that global tea consumption in 2022 was about 6.7 billion kilograms according to Statista, it’s safe to say we’re producing tea-leaf waste in the billions of kilograms, at least. Now, this isn’t an issue since it’s all organic material that can decompose pretty easily (unless discarded in a plastic tea bag). What if we told you that these tea leaves carry some wonderful benefits for plants? Just like used coffee grounds, used tea leaves can be recycled for your compost!

Tea Leaf Compost: What Tea Leaves Can Do for Your Plants

Tea leaves don’t just carry health benefits for humans. They also carry some really wonderful nutrients that, when added to soil or compost, can benefit plants immensely. Let’s get into some of the benefits that leaves add to soil below!

1. Nutrient-Rich

Multiple studies have found that tea leaves contain nitrogen, phosphorus, and potassium. Nitrogen is incredibly important for plant growth, plant metabolism (how fast it converts plant ‘food’ to energy for survival), and for overall plant-crop yield. Along with phosphorus and potassium, it is also a necessary nutrient for the process of photosynthesis in plants.

Phosphorus also helps plants spread and grow faster, along with boosting root growth. Potassium allows plants to regulate their water, CO2, and oxygen concentrations, and is taken up by plants in very large quantities.

Which Tea Leaves Have the Highest Concentration of Nutrients?

In terms of nutrient concentrations, Green and Black tea leaves are both packed with nitrogen. Green tea leaves are an especially potent source of nitrogen. This is why some studies even recommend adding raw tea leaves to plant soil and compost. Oolong and white teas are a close second in terms of nutrient-benefits to soil, but haven’t been studied to the extent as black and green tea. For masala chai tea, it’s recommended that milk-and sugar infused tea leaves aren’t added to soil, as it can lead to mold.

2. Improves Soil Structure

Tea leaves carry some microbes and bacteria with them, which can improve soil structure through soil aeration. The leaves allow the soil to retain moisture and nutrients better, and through aeration, which helps roots to grow freely. Nitrogen also boosts populations of decomposing bacteria in the soil.

3. Natural Pest Control

Tannins in tea leaves have been said to ward off all kinds of pests – from mice to insects. Tannins are specifically potent in black and oolong teas, especially post-brewing. Spraying plain, cooled tea on plants can hence possibly help get rid of any leaf-eating bugs, and adding it to compost can help keep it pest-free.

4. Increases Soil Acidity

Tannic acid is another potent compound found in tea leaves. Adding used tea leaves to the soil increases its acidity, lowering its pH. This is extremely useful for acid-loving plants such as Camellias, Magnolias, Tomatoes, Ferns, Roses, Cranberries, and Blackberries – to name a few.

How to Add Used Tea Leaves to Soil

1. Add them To Compost

The quickest and easiest way to recycle used tea leaves is by adding them to your compost pile or bin. Mix tea leaves with other compostable materials like kitchen scraps, grass clippings, and dried leaves. The composting process will break down the tea leaves, turning them into nutrient-rich compost that can be added to your garden soil.

2. Mulching

You can also place a layer of dried, used tea leaves as mulch around the base of your plants. This can help conserve soil moisture, regulates soil temperature, and provides a slow-release source of phosphorus and other compounds as the leaves decompose.

3. Water Your Plants with Tea

You can also water your plants with cooled tea. This should be dilute preparation, with lots of water – it can be sprayed on plants as a pest-control as well as to water your plants. It isn’t recommended that you use this daily, as the acid may be harmful if used too often.

4. Directly Add Tea Leaves to Soil

To reap the same benefits as you would with compost, this last point is also any easy method of utilizing the benefits of tea leaves for your plants. Be sure to thoroughly mix in the dry tea leaves with your plant soil.

A Note on Using Tea Bags in Compost

A lot of us prefer tea bags to loose tea leaves for their convenience. However, it must be noted that not all tea bags are compostable (not just biodegradable). Teabags that are compostable have no plastic, and fashioned entirely out of natural starches like cornstarch. These can easily decompose in soil and compost.

Plastic teabags (along with any stapler or glue-like materials) will not decompose, which can produce extra waste in plant soil. It’s recommended that you empty the teabags into soil instead – or if they’re compostable, tear them open so that the tea can decompose quicker.