Are Coffee Grounds Good for Tomato Plants?

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coffee grounds tomato plants

In the past we’ve talked about what effect coffee grounds can have on plants, but we haven’t discussed whether coffee grounds can make good fertilizer for vegetable plants, especially tomato plants.

There is a lot of information out there about how to properly fertilize your tomato plants and what products to use for the best results, but will coffee grounds will improve the success of your tomato plants?

The honest answer is, maybe.

I know that’s not what a lot of people like to hear, but it’s the truth. While there hasn’t been any scientific proof that coffee grounds will improve the rate of growth or number of tomatoes your plants produce, there is some scientific data that backs up the reasoning for why people believe that coffee ground are good for tomato plants.

Tomato Plants Like Slightly Acid Soil

The main reason that this idea that coffee grounds can help to fertilize your tomato plants is that tomato plants thrive in slightly acidic soil. Used coffee grounds can help soil become slightly more acidic when they are used as fertilizer.

Now, when we say slightly more acidic, we do mean slightly.

In some cases, coffee grounds could actually be alkaline or neutral meaning they are not acidic and therefore not helping the plants, but in most cases the grounds are just acidic enough to help the soil, but not by much.

Coffee grounds contain around 2% nitrogen as well as varying amounts of phosphorus and potassium which are all very important for the growth of tomato plants. By mixing some coffee grounds into the soil below your tomato plants you’re introducing these nutrients that the plants need to thrive.

However, coffee grounds do not act like traditional fertilizer and will take some time to affect the soil enough to help the plants. In fact, it may have the opposite effect on the soil for a couple weeks before releasing enough of the nutrients in the soil to help.

This is why people claim that coffee grounds help out with tomato plants over the long run, but not necessarily during the up front growing. So, keep that in mind if you’re looking for something to help get your plants growing quickly.

Should You Use Coffee Grounds to Fertilize Tomato Plants?

Knowing the information above, there’s nothing wrong with using some of your used coffee grounds to help fertilize your tomato plants, but don’t expect some miracle growth hack to come from it. You also need to make sure that you’re not overdoing it by using too much on your plants.

Take about 1 cup of used coffee grounds spread around the base of your tomato plant and work it into the top 2-3 inches of the soil. This will help the coffee grounds break down and start to release the nutrients into the soil.

You can also use coffee grounds in a compost bin and then use that compost as fertilizer to help the plants grow. Just make sure that you keep the coffee grounds to less than 20% of the compost material as you don’t want to make the compost too acidic. This can be more harmful than good for the tomato plants.

Traditional Fertilizer vs. Coffee Grounds

If you’re looking for a fertilizer to help improve your tomato plants in the best way possible, and you’re open to using store bought fertilizer, there are options out there that are specifically designed for these types of plants and will most likely offer greater benefits than coffee grounds would.

If you would rather not use those types of fertilizers though, used coffee grounds are a great, natural, way to help create a more suitable soil for the tomato plants to thrive in.

Coffee grounds can be very useful when it comes to gardening, but it’s important to understand why plants may benefit and how to properly use them to achieve the best results possible.

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