Do you find yourself left with a pile of used coffee grounds after your morning brew, and wondering what on earth to do with it all? Well, your plants might just have the answer!
But hold on, don’t just toss those grounds into your indoor garden just yet. We’re here to spill the beans on the dos and don’ts of coffee grounds in plant care, ensuring your treasured green buddies stay perky and happy. Stay tuned!
Why are Coffee Grounds Good for Plants?
Did you know your delicious morning brew leaves behind a little treasure called coffee grounds? They’re the chunky remnants at the bottom of your coffee pot, packed with all sorts of plant-friendly nutrients.
Coffee grounds are like the unexpected superheroes of the plant world. They’re loaded with nutrients and minerals that plants just love. If nitrogen was money, coffee grounds would be millionaires, providing a rich source of this essential plant growth nutrient. Coffee grounds contain minerals like nitrogen and phosphorous that encourage healthy growth of plants.
But before you dump your fresh coffee grounds to every houseplant around the house, hold on! While some plants absolutely thrive when you fertilise them with coffee, there are also many that don’t like it quite as much.
The Science Behind Coffee Grounds as Fertilizer
Coffee grounds, those granular leftovers from your daily brew, are much more than just waste. They’re packed with compounds and nutrients that can significantly benefit your houseplants when used correctly.
The magic behind used coffee grounds lies in their ability to alter soil structure and pH levels. Here’s the cool part: coffee grounds can help adjust soil pH for acid-loving plants (looking at you, African violets and Christmas cacti!) and improve the feel and fertility of the soil.
But how exactly does this work? Well, let’s don our lab coats and step into the world of plant science for a moment.
1. Nutrient Rich
First things first, coffee grounds are rich in essential organic materials and nutrients that plants need to grow, namely nitrogen, phosphorus, and potassium. Nitrogen, in particular, is vital for plant growth as it’s a primary component of amino acids, proteins, and chlorophyll. Essentially, nitrogen is like the protein shake for your plants, helping them build strong structures and promote growth.
2. Acidic Nature
Next, we need to talk about pH. In the simplest terms, pH measures how acidic or alkaline something is. Now, most coffee grounds have a pH that is slightly acidic, which can be a big plus for acid-loving plants like African violets or rhododendrons. The coffee grounds can help to gently lower the soil’s pH, creating an ideal environment for these plants to thrive. Coffee grounds are acidic and can be used with plants that crave acidity to change the pH level of the soil.
3. Improving Soil Structure
Adding coffee grounds to your soil also improves its structure. You see, the grounds help to increase the soil’s ability to hold onto water (also known as water retention), which can be a game-changer, particularly for those of us who sometimes forget to water our plants. Improved water retention means your plants have more time to drink up the water they need.
4. Slow-Release Fertilizer
When you add coffee grounds to your soil, they don’t just dump all their goodness at once. Instead, as the grounds break down, they slowly release their nutrients. This is great because it provides a steady supply of nourishment for your plants over a longer period, unlike synthetic fertilizers that release all their nutrients at once.
5. Pest Control
The science doesn’t stop at plant growth and soil health, though. Coffee grounds can also deter certain pests. You see, many creepy crawlies, like slugs and snails, aren’t fans of the abrasive texture and caffeine content of coffee grounds. So, adding coffee grounds to your soil can help keep these pesky critters at bay.
But remember, not all plants are coffee lovers. Some prefer more alkaline soil or are more prone to coffee’s potential negative impacts like fungal diseases. So, always do your homework before inviting your plants to the coffee party!
And that’s your crash course on the science of coffee grounds as a natural fertilizer. Pretty cool, right? Your morning brew not only wakes you up but can give your plants a boost too!
When to Use and When to Avoid Coffee Grounds
While coffee grounds can be a great fertilizer for many plants, there are times when it’s best to avoid them:
- Alkaline-Loving Plants: Some plants prefer alkaline soil, and coffee grounds, being acidic, could disrupt their happy environment. This includes plants like the spider plant, jade plant, and yucca.
- Disease-Prone Plants: Coffee grounds can create a conducive environment for certain fungi that cause plant diseases. If your plants are susceptible to fungal disease, it’s best to skip the coffee grounds.
Coffee grounds are best used with acid-loving plants, like miniature roses and snake plants. But for plants that are more into alkaline vibes (like lavender), it’s a no-go. Remember, it’s all about balance!
Potential Risks and Drawbacks
But wait, before you run off to dump that old coffee on your Jade plant, let’s hit pause. Like most good things, coffee grounds need moderation. Too much, and you might see water retention, fungus gnats, or even fungal disease (yikes!) creeping in. Also, remember, fresh coffee grounds are like a double espresso—too strong. Stick with the used ones.
Myths and Misconceptions
There are a few myths brewing in the coffee ground world. Some people think that all plants love coffee. Sorry to spill the beans, but that’s not true. Some plants, especially those preferring alkaline soil, might turn up their leaves at a coffee treat.
How to use coffee grounds as fertilizer
With the wonders of coffee grounds for plant growth in mind, it’s time to learn how to put those coffee leftovers to good use in our indoor garden. Let’s dive into the “grounds” of things!
1. Prepare Your Coffee Grounds
Here’s where it all begins. After you’ve enjoyed your cup of joe, instead of tossing the used coffee grounds, save them. You can collect them in a container and let them dry. This is a key step since fresh coffee grounds are quite acidic and could harm your plants.
2. Directly to the Soil
One of the easiest ways to use coffee grounds is to add them directly to the top of the soil in your plant pots. Just sprinkle a small amount around the base of your plants, and let the nature do its work. The grounds will slowly break down, releasing nitrogen and other nutrients into the soil. Think of it as a dusting of cocoa on top of your cappuccino—only a small amount, please!
3. Mix it in Your Compost Pile or Potting Mix
Coffee grounds make a great addition to your compost pile. Mix them in, and they’ll contribute valuable organic matter as they decompose. Alternatively, you can mix coffee grounds into your potting mix before planting. About a 1/4 to 1/3 ratio of coffee grounds to potting soil should do the trick.
4. Brew a Coffee Grounds Tea
If you prefer a more “brew-tiful” method, you can make a liquid fertilizer with your coffee grounds. Simply add 2 cups of used grounds to a 5-gallon bucket of water, let it steep overnight, and voila – you’ve got yourself a coffee ground tea! You can use this concoction to water your plants every few weeks. This is usually the safest way to prevent spreading diseases.
Tips and Tricks for Using Coffee Grounds Effectively
Now, let’s spill the beans on some tips and tricks for using coffee grounds effectively:
- Moderation is Key: Just like how too much coffee can make us jittery, too much can overwhelm your plants. Using a small amount of coffee grounds can give your plant growth an extra boost, but avoid using them too frequently.
- Monitor the Effects: Keep an eye on your plants and soil after applying the coffee grounds. Look for changes in leaf color and check the soil’s pH levels. Coffee grounds can make your soil more acidic, which some plants might not appreciate.
- Fresh is Not Best: Fresh coffee grounds are more acidic than used ones, and can be toxic to plants. Always use used coffee grounds, and allow them to dry before applying to soil.
Suitable Houseplants for Coffee Grounds Fertilizer
From the dainty African Violet to the stoic Snake Plant, many of your houseplants could benefit from a dash of coffee. So put on your gardening gloves, and let’s dive into the world of houseplants that would happily say yes to a coffee date!
1. African Violet (Saintpaulia)
What a darling! African violets are compact, always ready for a photoshoot with their clusters of white, blue, or purple flowers. They are the coffee lovers of the plant world, preferring slightly acidic soil (pH 6.0-7.0). A sprinkle of used coffee grounds every two months is their idea of a gourmet meal.
2. Cyclamen
Cyclamens are the supermodels of houseplants, flaunting unique flower shapes in a rainbow of colors. They love a little acid too, thriving in a pH of 6.0-7.0. Treat your cyclamen to a coffee ground sprinkle every couple of months, but remember, a little goes a long way!
3. Rhododendron
Rhododendrons are like the wise old elves of the plant world, with their vibrant clusters of bell-shaped flowers and large, dark leaves. They thrive in acidic soil (pH 4.5-5.5). Your coffee grounds? They’re all in! Sprinkle on top of the soil monthly, and they’ll thank you with a stunning floral show.
4. Christmas Cactus (Schlumbergera)
The Christmas Cactus is the life of the party, blooming right in the heart of holiday season. They’re not too fussy about pH but don’t mind a bit of coffee ground indulgence (pH 5.5-6.2). A monthly dose should keep the party going!
5. Pothos (Epipremnum aureum)
Sometimes referred to as the ‘Devil’s Ivy,’ Pothos is the easy-going, low-maintenance buddy that adds a touch of green to any room. They’re not picky about pH (6.1-6.5), but they won’t say no to a little coffee ground treat every month or two.
6. Philodendron
Known for their large, often split leaves, Philodendrons are pretty chilled about their growing conditions, though they prefer slightly acidic to neutral pH (5.5-7.0). Introducing coffee grounds every other month can make them feel extra special.
7. Miniature Roses
These small yet sophisticated houseplants can make any space look elegant. They enjoy a bit of acidity (pH 6.0-6.5). Feeding them a dose of coffee grounds every two months should keep them blooming beautifully.
8. Jade Plant (Crassula ovata)
A gem among succulents, Jade Plants love well-drained soil and can tolerate a wide pH range (6.1-7.8). As they’re prone to root rot, sprinkle a small amount of coffee grounds every three months, and they’ll continue to grow strong.
9. Snake Plant (Sansevieria trifasciata)
The Snake Plant is the strong, silent type, purifying the air while asking for very little. They’re comfortable in a wide pH range (4.5-8.5). Treat them to coffee grounds sparingly, maybe once every three to four months.
10. Spider Plant (Chlorophytum comosum)
The Spider Plant is as chill as they come, happy in a variety of conditions and pH levels (6.0-7.2). A touch of coffee grounds every few months should keep their green and white leaves vibrant.
11. Camellias
Camellias, with their stunning blooms, have a penchant for acidic soil (pH 6.0-6.5). Sprinkling coffee grounds around them monthly can help them bloom beautifully. But remember, they’re just like that friend who likes their coffee light, not too strong.
12. Azalea
These gorgeous flowering shrubs are also fans of acidic soil (pH 4.5-6.0). Give them a monthly dose of coffee grounds, and watch them flourish. Just remember not to go overboard, or they might end up needing a coffee detox.
13. Peace Lilies (Spathiphyllum)
These graceful plants are a symbol of peace and tranquility, and they love a bit of nitrogen. But they like their coffee like their lifestyle – peaceful and mild. So, it’s best to use composted coffee grounds for them, once every two months.
14. Lily of the Valley (Convallaria majalis)
Known for their sweet-smelling, bell-shaped flowers, these beauties thrive in acidic soil (pH 5.0-6.0). Adding coffee grounds to their soil monthly can make their day and boost their growth.
15. Begonias (Begonia semperflorens)
These bedding plants are lovers of acidic soil (pH 6.0-6.5), so lightly sprinkle some coffee grounds around them once a month. They like their coffee subtle, not overwhelming.
16. Blueberries (Vaccinium spp.)
Although not your typical houseplant, blueberries can grow in pots and absolutely love acidic soil (pH 4.5-5.5). A little bit of coffee grounds every two weeks can make them berry happy!
17. Fuchsia (Fuchsia spp.)
Known for their dangling, brightly colored flowers, Fuchsias thrive in slightly acidic to neutral soil (pH 6.0-7.0). They’ll appreciate a coffee treat once a month, making your care for them truly fuchsia-nating!
18. Gardenia (Gardenia jasminoides)
If your Gardenia could walk, it would probably stroll right into a coffee shop. Loving acidic soil (pH 5.0-6.5), Gardenias would thrive with a sprinkle of coffee grounds every two weeks.
19. Magnolia (Magnolia grandiflora)
As indoor bonsai, Magnolias enjoy slightly acidic soil (pH 6.0). Treat them to a coffee grounds top-dressing once a month, and they’ll thank you with robust growth.
20. Marigolds (Tagetes spp.)
A great indoor plant for beginners, Marigolds thrive in slightly acidic to neutral soil (pH 6.0-7.2). A monthly sprinkle of coffee grounds can keep them blooming beautifully.
21. Heather (Calluna vulgaris)
Often used as an indoor decorative plant, Heathers love acidic soil (pH 4.5-5.5). A sprinkling of coffee grounds once a month can really make them thrive!
22. Japanese Pieris (Pieris japonica)
This stunning plant, often used as a bonsai, likes a soil pH of around 5.5. Treat them with coffee grounds every two weeks, and they’ll reward you with vibrant growth.
23. Hydrangea (Hydrangea macrophylla)
Indoors, these beauties need lots of care and an acidic soil (pH 5.0-6.0). Biweekly coffee treatments can help keep them blooming!
24. Amaryllis (Hippeastrum spp.)
A popular holiday plant that prefers slightly acidic soil (pH 6.0-6.5). They’ll appreciate a monthly sprinkle of coffee grounds.
25. Anthurium (Anthurium andraeanum)
With a soil pH preference of 5.5-6.5, the flamingo flower will appreciate coffee grounds added to its pot once a month.
26. Impatiens (Impatiens walleriana)
A great indoor plant that enjoys slightly acidic to neutral soil (pH 6.0-7.0). A monthly dose of coffee grounds will keep them blooming continuously.
27. Japanese Maple (Acer palmatum)
An excellent choice for bonsai, Japanese Maples thrive in slightly acidic soil (pH 5.5-6.5). Biweekly coffee ground treatments can help maintain their vibrant colors.
28. Mint (Mentha spp.)
Indoor mint plants can benefit from slightly acidic soil (pH 6.0-7.0). Add coffee grounds every two weeks to keep them fresh and thriving.
29. Parsley (Petroselinum crispum)
Yes, even your herb garden can use a coffee boost! Parsley prefers a neutral pH but won’t mind a slight acid tilt (pH 6.0-7.0). Try adding coffee grounds once a month.
30. Swiss Chard (Beta vulgaris subsp. vulgaris)
Growing Swiss chard indoors can provide you with a fresh supply of greens. They can handle a wide pH range (pH 6.0-7.5) but won’t say no to a monthly coffee treat.
31. Violas (Viola spp.)
These charming plants are a great indoor addition and prefer slightly acidic to neutral soil (pH 6.0-7.0). Sprinkle some coffee grounds every month to help keep their vibrant colors.
32. Zinnia (Zinnia spp.)
For indoor growers, Zinnias can add a pop of color. They thrive in a slightly acidic to neutral pH (6.0-7.0) and would appreciate coffee grounds once a month.
33. Camellia (Camellia japonica)
As we mentioned before, these beauties adore acidic soil (pH 4.5-5.5) and will bloom even brighter with a biweekly coffee ground boost.
34. Hibiscus (Hibiscus rosa-sinensis)
This flowering plant is a popular houseplant known for its large, bright, trumpet-shaped flowers. Hibiscus prefers acidic soil, making coffee grounds a beneficial addition. Remember to mix coffee grounds into compost before application, as direct application can clump and hinder water absorption.
35. Caladium (Caladium bicolor)
Also known as Elephant Ear, as a plant native to South America’s rainforests, Caladium enjoys acidic conditions, so the addition of coffee grounds can help maintain the soil’s pH level. Mix the coffee grounds into the compost before applying.
36. Flamingo Flower (Anthurium)
This popular houseplant prefers a pH level between 5.5 and 6.5, which can be maintained by adding coffee grounds to your compost pile. However, apply sparingly and always in combination with compost to prevent water retention issues.
37. Coleus (Coleus spp.)
It’s frequently grown as a houseplant because of its vibrant, patterned leaves in shades of green, yellow, pink, red, maroon, etc. A fan of well-draining soil, Coleus can appreciate the extra texture and acidity brought by coffee grounds. Plus, the additional nitrogen can encourage lush growth.
Remember, each plant is unique, just like us, and they may react differently to coffee grounds. So, it’s always a good idea to start small and observe how your plant responds. Then you can adjust the coffee ground servings to suit their taste, ensuring they thrive in your indoor garden.
Unsuitable Houseplants for Coffee Grounds Fertilizer
Here are examples of some common houseplants that you should avoid putting coffee grounds into. Many of these are houseplants that prefer alkaline soils or are sensitive to diseases.
1. Orchids
Prefers a bark-based growing medium, not regular soil. Coffee grounds can alter this delicate balance.
2. Lavender
Prefers alkaline soil, coffee grounds might make the soil too acidic for them.
3. Black-eyed Susan
Typically prefers a neutral to alkaline soil.
4. Asparagus Ferns
Like Lavender, these prefer a more alkaline soil.
5. Devil’s Ivy
Can be sensitive to the acidity in coffee grounds.
6. Cactus
They prefer a more alkaline, sandy soil and can be harmed by the added moisture retention from coffee grounds.
7. Century Plants
Similar to cacti, they prefer alkaline conditions.
8. Rosemary
Prefers a neutral to slightly alkaline soil.
9. Geraniums
Prefer a more neutral pH level.
10. Coral Bells
Prefer neutral to slightly acidic soil, coffee might make the soil too acidic.
11. Aloe Vera
Prefers dry conditions, and coffee grounds may retain more moisture than these plants would like.
12. Begonia
The added moisture from coffee grounds might encourage fungal diseases in Begonias.
13. California Poppies
Prefer poor to moderately fertile soils.
14. Oxalis
These plants can be sensitive to the extra acidity from coffee grounds.
15. Boxwood (Buxus sempervirens)
Often used as a topiary or bonsai plant, it prefers a slightly alkaline soil (pH 7.0-8.0).
16. Boston Fern (Nephrolepis exaltata)
This popular houseplant enjoys neutral to slightly alkaline conditions (pH 7.0-7.5).
17. Yucca (Yucca elephantipes)
A beautiful indoor plant that prefers alkaline conditions (pH 7.5-8.5).
18. Kentia Palm (Howea forsteriana)
An indoor palm that loves a neutral to slightly alkaline soil (pH 6.5-7.5).
19. Baby’s Breath (Gypsophila paniculata)
Often grown indoors in containers, it thrives in neutral to slightly alkaline soils (pH 7.0-7.5).
20. Butterfly Bush (Buddleja davidii)
While commonly grown outside, some enthusiasts grow this as a container plant indoors. It prefers neutral to slightly alkaline conditions (pH 6.5-7.5).
20. Sweet Alyssum (Lobularia maritima)
Great for indoor hanging baskets and prefers slightly alkaline conditions (pH 7.0-7.5).
21. Clematis (Clematis spp.)
A popular climbing plant for indoor use, Clematis thrives in neutral to slightly alkaline conditions (pH 7.0-7.5).
22. Chrysanthemum (Chrysanthemum morifolium)
A staple in many homes, it prefers neutral to slightly alkaline soil (pH 6.5-7.5).
Frequently Asked Questions
What plants do coffee grounds help grow?
Coffee grounds can help grow plants that crave acidity by changing the pH level of the soil. Some examples of these plants include African Violet , Cyclamen , Rhododendron , azaleas and camellias .
Do Monstera like coffee grounds?
Monstera generally likes a coffee fertilizer. While they are no substitutes for regular fertilizers, they can help improve the soil structure. But you have to proceed with caution as they can also cause harm by promoting fungal growth and attracting fungus gnats. Use coffee ground “tea” to prevent causing harm.
Is coffee good for all plants?
No, coffee is not good for all plants. Some plants do not like acidic soil or high nitrogen levels in the soil and should not be fertilized with coffee grounds.
Can I use fresh coffee grounds as fertilizer?
It is recommended to use used coffee grounds rather than fresh ones as fertilizer for plants. Fresh coffee grounds are highly acidic and can be toxic to plants .
How often should I use coffee grounds as fertilizer?
The frequency of using coffee grounds as fertilizer depends on the specific needs of your plants. It is best to start small, observe your plants’ health and growth, and adjust accordingly.
Bottom Line
You’re not just a coffee lover anymore, you’re also a coffee grounds recycling champ! Reusing old coffee grounds as fertilizer is a great way to give your indoor plants an extra boost during the growing season. Let’s take a moment to espresso our main takeaways:
- Fertilizer – Remember, composting coffee grounds before use is the safest bet. No one likes a heartburn, not even your plants.
- pH levels – Keep an eye on those. Acidic soil is not everyone’s cup of tea, er… coffee.
- Coffee ground tea – Might not be the tastiest brew for us, but your plants are going to love a sip. It is usually better than just sprinkling coffee grounds on top of the soil.
- Unsuitable houseplants – Not all plants are coffee aficionados. Make sure you’ve checked whether your green friend likes it before going all barista on them.
So next time you finish your cup of black coffee, think twice before tossing those grounds away!