Soothing, rich in antioxidants, and good for the heart, tea is one of the most wondrous herbal beverages known to man. A mixture of carefully selected plant parts and their essential oils, it is packed with phytochemicals that can aid in boosting one’s immunity. It isn’t just great for us humans, however; it can be remarkably beneficial for plants too!
Tea in virtually any form – the leftover dregs of tea leaves in a cup, the infused water, or even used teabags – can be reused in the garden. Naturally rich in nitrogen, phosphorus, potassium, and tannins, it can help nourish, hydrate, and fertilize a wide range of nutrient-hungry herbs, shrubs, and trees. Depending on its formulation, it may have higher nutrient concentrations than store-bought fertilizers.
As tea tends to be acidic, it is best used for plants that prefer low pH levels. Exposing the wrong set of plants to tea can cause them to wilt or grow at a slower pace. In contrast, applying tea leaves around the right set of plants can improve leaf production and hasten root development.
For best results, mix tea or used tea leaves into compost instead of applying them directly over your plants. The tea-enriched compost should then re-invigorate your plants in a more well-balanced manner.
1) Ferns (Polypodiophyta spp.)
With a general morphology that has been largely conserved for millennia, ferns are often perceived as living fossils. These hardy plants, typically found in woodlands and tropical forests, rely on physical forces (e.g. water, air) to colonize habitats and expand their distributions. They are found in virtually all types of climates, though their species richness is highest in warm areas with consistently moist substrates.
Nowadays, ferns are favored by landscapers and horticulturists for their ease of care and their ornamental appeal. When provided with ample moisture, shade, and nutrients, they can quickly produce their complex fronds. In terms of their need for fertilizer, ferns are known for being light feeders. Nonetheless, they do benefit from a proportioned mix of supplementary nutrients. As many of them are acid-loving, they can flourish when provided with tea-infused compost!
Not all ferns will benefit from tea in the same way. Evergreen ferns that are native to habitats with stained and low-pH waters, like bogs and swamps, are more likely to appreciate tea leaves. Some common indoor species (e.g. the maidenhair fern), on the other hand, would need to be fertilized with caution as they may prefer slightly alkaline soils.
2) Azalea (Rhododendron spp.)
Members of the Ericaceae or heather family, azaleas are temperate shrubs. Known for thriving in partly shaded areas, such as below the canopies of larger shrubs or trees, their perennial bushes can significantly brighten up dim spaces, especially during their lengthy bloom period. Though they are unfortunately slow-growing, they are well worth the extra patience. Their inflorescences can be dense enough to transform the look of the entire plant!
In the wild, azaleas tend to be found in riparian habitats and in wetlands. They may occur as border plants close to the edges of streams and swamps. For this reason, they are more tolerant of acid-rich soils than many other terrestrial plants. Humus-rich substrates with pH levels ranging from 4.0 – 7.0 are oftentimes best for their root expansion and overall productivity.
These acid-loving plants are the perfect recipients of the concentrated nutrients found in tea bags and used tea leaves. Simply bury a used tea bag in the soil, a few inches clear of azalea roots. Over time, the nutrients should gradually seep out and spread throughout the azalea plot or container. This is a great way to raise the acidity levels around azalea shrubs without risking the roots of other nearby plants.
3) Roses (Rosa spp.)
There’s nothing quite like a row of productive rose bushes, especially during their bloom season. With hundreds of prized cultivars and varieties, there’s a rose for just about any type of garden and climate. These ornamental plants have been cultivated and developed for millennia to meet an endless demand for their fresh blooms, strongly-scented oils, and edible parts. For many horticulturists, the secret to their lushness lies in maintaining the acidity of the soil!
The tannins in tea leaves can effectively aid in lowering pH levels around rose bushes. These are especially handy in gardens that tend to have neutral to slightly alkaline conditions. To encourage roses to grow rapidly and produce an adequate amount of buds, it would be advisable to maintain substrate pH levels at around 6 – 6.5. Some gardeners may combine used tea leaves with coffee grounds, taking care to evenly sprinkle them around the base of well-developed shrubs.
Tea is best supplied to roses in spring, when they have entered their most active stage of growth. Note that, while tea leaves are beneficial for roses in plots with limestone-rich or neutral conditions, they would not be ideal for soils that are already acidic to begin with. Prior to liberally sprinkling tea leaves around your yard, aim to accurately test your soil’s pH levels.
4) African violets (Streptocarpus sect. Saintpaulia)
African violets are low-growing plants with notably delicate features. Found only in the forests and coastal habitats of countries like Tanzania and Kenya, they favor tropical conditions. Extremely popular as houseplants due to their vibrant, bouquet-like inflorescences, they are known for being quite sensitive to light exposure, soil pH, drainage, and temperature. Simply spilling cold water on the leaves of some cultivars, for example, can cause them to become discolored.
The challenge that comes with growing these finicky plants is precisely what appeals to many experienced home gardeners. Finding the right balance of conditions is rewarding as this species’ blooms can be so elusive in the wild. Once you manage to maintain soil and moisture parameters, however, you’ll find that these plants can fare well in neglect.
Keeping the soil pH at slightly acidic levels, specifically between 5.8 – 6.2, is necessary for optimizing the roots’ capacity to absorb nutrients. Using tea is a great hack for encouraging the prolific production of African violet blooms! Simply let used tea leaves sit in a jar of clean water for a few days, strain out the leaves, and then pour the strained liquid into the substrates surrounding your violets.
5) Hortensias (Hydrangea spp.)
One of the secrets to successfully growing hortensias lies in keeping the soil pH at a strictly acidic range. Though hydrangeas can tolerate neutral and even slightly alkaline soils, they tend to bloom most profusely when they are rooted in substrates with pH levels from 5.2 to 5.5. This is excessively acidic for many other plants, so the section just right beneath their crowns may be given an extra dose of acid in the form of tea water or used tea leaves.
Some hortensia species, such as bigleaf hydrangea (H. macrophylla), have the remarkable ability to produce pigments that are directly associated with pH levels in the substrate. Low pH levels, which affect the roots’ absorption of aluminum ions in the soil, usually lead to the production of blue flowers. Slightly higher pH levels may lead to the development of pink to red blooms. Species with white flowers are unable to depict changes in soil pH, though they are also more likely to thrive in slightly acidic soils.
Growing pigmented hortensias and experimenting with soil pH levels is a great way to promote the production of a range of petal colors. In some cases, a single plant may have blue, purple, and pink inflorescences! Try fertilizing alternating shrubs to have a balanced array of colors.
6) Daffodils (Narcissus spp.)
Widely cultivated as spring-blooming bulbs, daffodils are set apart by their conspicuous blooms. Equipped with a set of bright petals encircling a vividly-colored corona, these herald the onset of warming temperatures in late winter or early spring. To bloom at the right time, the bulbs must be planted in early fall. The right set of substrate and atmospheric conditions should then awaken them as soon as the final frosts pass.
To successfully produce their strap-shaped leaves and bloom stalks, daffodil bulbs should be situated in slightly acidic substrates. Though some varieties may prefer slightly alkaline soils, most of these plants may require acid-rich supplements to efficiently absorb nutrients. Used tea leaves can help boost daffodil growth, but only in soils with primarily neutral or alkaline conditions. A tea-infused compost, to maintain pH levels at around 6 – 6.5, would be preferable.
7) Spider plant (Chlorophytum comosum)
A low-maintenance houseplant, C. comosum is known for being remarkably resilient. It is named for the spider-like appearance of its tufts of grass-like leaves. Over time, mature specimens of this species begin to send out branching inflorescences. These gracefully cascade from elevated or hanging pots to produce clusters of suspended plantlets. Once these come into contact with the appropriate substrates, they develop their own roots.
With a preference for loamy, slightly acidic substrates, the spider plant thrives beneath tree canopies and other warm, partly shaded areas. Handy for filling in gaps in tropical rock gardens, it is often favored for its non-toxic profile and its ease of propagation. As its roots efficiently absorb nutrients in pH levels between 6.0 – 6.5, the tannins in tea water and used tea leaves can give it a healthy nutritional boost.
When adding tea to a patch of spider plants, aim to dilute it to avoid shocking the roots. A low concentration of tannins should be enough to refresh them. If you’re worried about excessively fluctuating pH levels, it would be prudent to keep a pH meter nearby. If pH levels dip to below 6, you may simply flush out the soil with a generous dose of neutral water.
8) Tomatoes (Solanum lycopersicum)
One of the most commercially important crops due to its versatility in the kitchen, the humble tomato now comes in all shapes and sizes. However, one aspect of this species remains the same among its hundreds of cultivars. No matter where these plants are grown, their fruits’ juices are acidic (pH 4.3 – 4.9). It thus comes as no surprise that the tart fruits are borne on plants with a preference for slightly acidic substrates.
Tomatoes grow best in soils with pH levels between 6.2 – 6.8. These plants are able to tolerate levels that go down to about 5.5 without diminishing in quality. They may survive in more acidic conditions but note that these may cause their shoots to become undersized. In small farms and gardens with neutral to alkaline soils, tea is great for bringing down pH levels to an optimal range.
Diluted tea or reused tea leaves contain low levels of nitrogen, phosphorus, and other trace elements. These can help improve the quality of tomato plants in their peak growth phase, during which a large portion of nutrients is allocated to bloom and fruit production. As a bonus, phytochemicals from the essential oils in tea leaves should help protect the roots from potential pests!
9) Rubber plant (Ficus elastica)
A member of the Moraceae or fig family, the rubber plant is now a common tropical houseplant due to the ornamental qualities of its sturdy trunk and its shiny leaves. Though it can reach towering heights of 100 – 130 feet (31 – 40 meters) in outdoor areas, it can be cut back to maintain a manageable size indoors. Moreover, restricting its root system to within pots or containers prevents its shoot from growing to massive heights.
The rubber plant now comes in several cultivars, some of which have variegated or intensely dark leaves. Regardless of leaf appearance, this species thrives best in soil mixtures with slightly acidic conditions. For high-quality leaves, aim to maintain pH levels at a range of 5.0 – 7.0. Of course, warm temperatures and moderate humidity conditions are also key to encouraging leaf production and longevity.
Compost tea, made by either infusing compost with tea water or by mixing in used tea leaves, is great for stimulating the growth of new rubber plant leaves. This can be applied around the base of the plant or worked into the top layers of soil. Rubber plants that are situated in limestone-rich soils outdoors can be provided with a more generous amount of tea, ideally during scheduled waterings.
