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Rumors fly and the debate rages on. As modern gardeners, we often question gardening tips we read online or were told by older gardeners. For example, are coffee grounds good for tomato plants? In this case, scientific studies have demonstrated whether or not tomatoes benefit from coffee grounds.
Coffee grounds have become a popular additive for tomato gardens over the years Gardeners swear by using spent coffee grounds to boost tomato growth and yield But is this just an old wives’ tale or is there real science behind it? As a tomato gardening enthusiast, I decided to dig deeper into the practice of using coffee grounds on tomato plants. Here’s a complete guide on the benefits, risks, and best practices for using coffee grounds in your tomato patch.
Why Use Coffee Grounds on Tomatoes?
There are a few key reasons why gardeners believe coffee grounds can help tomato plants:
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Adds nutrients Coffee grounds contain nitrogen phosphorus potassium, and other micronutrients that are beneficial for plant growth. The grounds release these nutrients slowly as they break down.
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Acidifies soil: Tomatoes prefer slightly acidic soil with a pH between 6.0-6.5. The acidity of coffee grounds can help lower soil pH into this optimal range.
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Improves soil texture: As coffee grounds break down, they can improve soil structure and texture, creating a better growing environment for tomato roots.
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Suppresses fungal diseases Compounds in coffee may help suppress certain fungal diseases that affect tomatoes like early blight verticillium wilt, and fusarium.
While the nutrient boost is the main reason behind the coffee grounds trend, the other soil benefits certainly don’t hurt!
Potential Risks of Coffee Grounds
Coffee grounds have the potential to cause issues if not used properly on tomatoes:
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Too acidic: Excessive application of grounds can make the soil too acidic for tomatoes. This can inhibit nutrient uptake.
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Nitrogen robbing: As grounds break down, microbes tie up nitrogen in the soil. This can deprive plants of nitrogen needed for good growth.
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Fungal diseases: If fresh grounds contain fungal spores, they could spread tomato diseases like verticillium wilt.
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Stunted growth: Overapplying coffee grounds can potentially burn plants or stunt their growth.
The key is moderation. When used sparingly, coffee grounds provide benefits without risks.
How to Use Coffee Grounds on Tomato Plants
Here are some tips on using spent coffee grounds as an amendment for your tomato patch:
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Mix into compost: Add grounds to your compost pile, limiting them to 20% of the total volume. The finished compost can be worked into soil.
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Top dress soil: Sprinkle 1/4-1/2 inch of grounds around plants, keeping it 3-4 inches away from stems. Till lightly into soil.
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Mulch plants: Place a thin layer of wet grounds around plants to suppress weeds and retain moisture.
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Make compost tea: Steep grounds in water for a nutrient-rich liquid fertilizer. Use compost tea to water plants.
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Amend potting mix: Mix a small amount of grounds into container tomato soil to provide nutrients.
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Use dried grounds: Brewed or dried grounds release nutrients faster. Fresh wet grounds can temporarily rob nitrogen.
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Limit frequency: Only apply grounds once every 2-3 weeks. Overusing them can cause issues.
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Don’t overdo it: More is not better when it comes to coffee grounds. Use sparingly for best results.
When to Apply Coffee Grounds to Tomato Plants
Timing your coffee grounds application matters:
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Planting time: Mixing a small amount of composted grounds into soil at planting gives tomatoes an early boost.
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During growing season: Top dressing soil with fresh grounds during the growing season provides steady nutrients.
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After first fruit set: Applying grounds after tomatoes start ripening boosts production and yields.
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Not right before planting: Fresh wet grounds can temporarily tie up soil nitrogen. Allow 2-3 weeks before planting tomatoes.
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Not in fall: Late applications can spur tender growth before winter. Apply grounds in spring and early summer only.
The Bottom Line on Coffee Grounds for Tomatoes
Used coffee grounds can be a great organic additive for tomato gardens. They slowly release essential nutrients, improve soil structure, and may help suppress diseases. However, excessive application of coffee grounds risks over-acidity and other issues.
Follow the best practices outlined here for using spent grounds safely and effectively. And as with any garden amendment, moderation is key. A little bit of coffee grounds can provide benefits, but more is not necessarily better. Pay close attention to your plants, and adjust your grounds application as needed.
With the right balance, coffee grounds can be a smart way to boost tomato plant growth, fruiting, and overall garden yields. But be sure to amend them into the soil weeks before planting, use them sparingly when top dressing, and limit high-volume applications like compost to the off-season. Follow these tips, and you can tap into the potential benefits of coffee grounds for lusher, healthier tomato plants.
Fact or Fallacy: Do Tomatoes Like Coffee Grounds?
The short answer is yes and no. Like any garden additive, too much of a good thing can be detrimental. Consider what happens when too much fertilizer is applied to the lawn. Instead of a lush green carpet of grass, the turf turns brown.
So yes, tomatoes can benefit from coffee grounds, but only in moderation. Here are some positive ways coffee grounds improve soil quality and growing conditions for tomatoes:
- Better for you: Coffee grounds have micronutrients like boron, calcium, copper, iron, magnesium, and zinc, as well as nitrogen, phosphorus, and potassium.
- Nitrogen is released slowly because microbes have to break down the proteins in coffee grounds before plants can use the nitrogen.
- Compatible pH – With an acidity measuring between 5. 5 to 6. 8, coffee grounds have a pH level that is good for tomatoes.
- Compostable: Coffee grounds can be added to compost as long as the carbon-to-nitrogen ratio is 20 to 24:1. It is best to keep the coffee ground component to 20% of the total volume of organic materials for the best results.
- Fungal suppression: Research has shown that microorganisms that eat coffee grounds can stop common tomato diseases like Fusarium, Pythium, and Sclerotinia.
How To Use Coffee Grounds For Tomato Plants
With an estimated 700 million cups (165,611,766 L. ) of coffee that Americans drink every day, keeping this waste product from the coffee business out of landfills is a green choice. Gardeners can get used coffee grounds from places like coffee shops and restaurants, as well as from home and work.
Here are a few ways to use coffee grounds in the garden:
- Compost for tomatoes—Coffee grounds mixed with leaves or sawdust make compost that gives tomatoes the nutrients they need and fights fungal diseases. Add compost to the soil or use it as mulch around tomato plants.
- Mulch – Spread a 1/2 inch (1. 3 cm. ) of fresh coffee grounds around tomato plants to keep the water in. There are natural chemicals in coffee grounds that may stop weed seeds from sprouting.
- Soil improvement: Planting tomatoes with coffee grounds in the soil helps good microorganisms grow. Earthworms eat the grounds and push them deeper into the ground, which also makes the soil better.
- Coffee ground “tea”—This liquid fertilizer can be used to water tomato plants, even though it’s really coffee. Make the tea by adding two cups (473 mil. ) of used coffee grounds to five gallons (18. 9 L. ) of water.
Again, moderation is the key when using coffee grounds on tomatoes. This java byproduct has phytotoxic qualities which can have an adverse effect on tomatoes when applied in excess.
Using Coffee Grounds As Fertilizer For Tomatoes | Why Use Coffee Grounds As Fertilizer
FAQ
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