Find out how using tea leaves in the garden can benefit plants, compost and mulch – and even deter pests
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We’re all for recycling, especially when it benefits our gardens. The latest discovery we’ve made? Using tea leaves in the garden can lead to healthier plants. Of course it can – faded memories suddenly return of parents emptying tea leaves over bountiful rose bushes.
But tea leaves are not just good for plants – they can boost compost and deter pests, too. We investigate the upsides – and downsides – of using tea leaves in the garden.
Tea is a beloved beverage for many, providing comfort and caffeine to start the day or relax in the evening. But did you know that those discarded tea leaves and grounds could actually provide benefits for your plants?
As a gardener, I’m always exploring ways to nourish my plants and improve soil health using natural methods. Tea grounds seem to offer potential as an organic fertilizer and soil amendment. But how exactly do they help, and are there any downsides to watch out for? Let’s take a closer look at the pros and cons of using tea grounds in your garden.
How Tea Grounds Can Help Plants
Providing Nutrients
Used tea leaves contain certain nutrients that are beneficial for plants. Most notably tea grounds are high in nitrogen which is key for healthy foliage growth. They also contain smaller amounts of phosphorus, potassium, and calcium. As the grounds break down, they gradually release these nutrients into the surrounding soil where plant roots can access them.
Compared to commercial chemical fertilizers, the nutrient levels in tea grounds are relatively low. However, they can still give your plants a helpful boost, especially when used in combination with other organic materials like compost. Over many seasons, routinely adding tea grounds to your garden beds helps enrich the soil.
Improving Soil Structure
In addition to nutrients, tea grounds provide organic matter to the soil. As they decompose, the grounds help improve soil texture, aeration, and moisture retention. Tea leaves contain tannins and lignin which can further enhance the soil as they break down.
This is particularly beneficial for heavy clay soils, helping to lighten them and allow better drainage. For potted plants, sprinkling some tea grounds into the potting mix creates a moisture-retentive medium for healthy root growth.
Acidifying Soil
The tannins in tea leaves give them mildly acidic qualities. When worked into soil, tea grounds help lower pH levels. For acid-loving plants like azaleas, blueberries, and camellias, this can create a more favorable growing environment.
However, it’s important to regularly test your soil’s pH before and after applying tea grounds. You don’t want to over-acidify the soil, as too low of a pH can start limiting nutrient availability for plants.
Deterring Pests
There are claims that sprinkling tea grounds around your plants can help deter certain garden pests. The caffeine and tannins found in tea may have insect-repelling properties Anecdotally, some gardeners report success using tea grounds to keep slugs, snails, cats, mice, and other critters away from precious plants.
However, research on tea’s pest-repelling abilities is limited. But it can’t hurt to give it a try! Used coffee grounds seem to work better for deterring slugs, but tea grounds may provide minor protection.
Potential Drawbacks of Using Tea Grounds on Plants
While tea grounds offer some benefits, there are also a few potential downsides to keep in mind:
Risk of Over-Fertilization
While composted tea grounds provide a slow-release fertilizer, applying fresh wet tea leaves directly to plant roots or seeds risks burning them The nitrogen in fresh grounds can damage plant tissues Composting helps reduce these risks. But even mature compost should not be over-applied, as excess nitrogen can accumulate and cause fertilizer burn.
May Attract Pests
Some sources claim that the scent of tea grounds can attract pests like Japanese beetles. So you may end up compounding your pest problems if they are drawn to the grounds. It’s unclear how widespread this phenomenon is, but something to monitor.
Can Make Soil Too Acidic
Lowering soil pH with tea grounds is great for acid-lovers like blue hydrangeas that turn blue in acidic conditions. But for plants that prefer neutral or alkaline soil, excess acidification from tea can start inhibiting their nutrient uptake. Best to regularly test pH when using tea grounds.
Caffeine Toxicity Risks
While reports are rare, there is the potential for caffeine toxicity if excess tea grounds are applied within a short timeframe. Plants like citrus trees are especially sensitive. To be safe, compost tea grounds before applying. And space out applications, avoiding heavy concentrations.
Best Practices for Using Tea Grounds in Your Garden
Based on my research and personal experience, I recommend following these tips to maximize benefits while avoiding issues:
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Compost used tea bags and grounds before applying to garden beds. Never use fresh, wet grounds directly on plants.
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Mix composted grounds into soil – don’t leave clumps sitting on the surface.
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Test soil pH routinely when adding tea grounds, especially around acid-sensitive plants.
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Alternate composted tea grounds with other organic fertilizers like manure compost. Don’t overdo it with the tea.
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Scatter tea grounds lightly around plants to deter pests, but monitor for attraction of pests like beetles.
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Use only small amounts of composted tea grounds around seedlings and transplants. Too much nitrogen can burn young plants.
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For potted plants, mix a thin layer of composted grounds into potting soil. Don’t create thick concentrated layers.
Following these best practices, tea grounds can be a beneficial supplement to your overall garden nutrition and pest control program. Take it slowly, monitor effects closely, and enjoy the benefits of repurposing this common kitchen “waste” in your garden!
Adding Nutrients and Improving the Soil
Used tea grounds and fresh tea leaves contain nutrients and tannic acid that, when added to the soil, create a more fertile environment for garden, landscape and container plants. Because tea grounds are natural, organic matter, they increase nutrient levels and improve soil quality as they decompose. This, in turn, increases the level of activity by earthworms and other beneficial microorganisms. Tea grounds added to the soil also provide benefits, such as improved oxygenation, that create a stronger root system for your plants. Because plants take water and nutrients in through their root systems, the result is more vibrant, healthier plants.
Soil pH and Acid-Loving Plants
It is important to note that not all plants respond well when tea grounds and used tea bags are added to the soil, directly or in compost form. The natural tannic acid inside tea leaves leaches into the soil with rainwater as tea grounds decompose, thereby lowering the soil’s pH and increasing acidity. This poses a problem for plants that require neutral to alkaline soils but creates the ideal conditions for acid-loving plants to thrive. Use fresh and used tea grounds only on acid-loving plants, such as rosebushes and ferns. The best way to monitor your soil’s acidity is through pH testing with a home test kit.
2 Min. Tip: How and Why We Use Tea Leaves in the Garden
FAQ
Which plants should I put tea grounds in?
Q: Which houseplants like tea grounds? A: Plants that enjoy slightly acidic soil benefit from tea grounds, including ferns, croton, schefflera, begonia, orchids, spider plants, rubber plants, African violets, and philodendrons. Q: How do I apply tea grounds to my plants?
Which plants don’t like tea leaves?
The top 15 plants that don’t like tea are: Baby’s breath, Boston ivy, Cactus, Carnations, Chrysanthemums, Dahlias, Daisies, Geraniums, Hibiscus, Hydrangeas (pink), Iris, Marigolds, Peonies, Poppies and Sunflowers.
Is it okay to water plants with tea?
That said, you should use tea only on your plants that like acidic soil.
Can I put used tea bags in my plants?
Tea leaves can be added to soil as extra fertilizer. Just be sure to remove the tea bag, which is usually not biodegradable.