Coffee grounds are very popular in the houseplant community for use as a natural fertilizer, but do spider plants like coffee grounds or should you keep them away from this type of plant?
In my experience, using coffee grounds directly on spider plants can present more problems than it will solve. Using coffee grounds in a compost heap is a great alternative as a source of nitrogen and this can be added to the potting soil for a spider plant to boost the nutrient profile.
There are arguments for both sides, however, and it’s important to consider both sides before you can make your own decision about using coffee grounds on your spider plant.
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How Coffee Grounds Can Be Used On Spider Plants
Let’s first take a look at how coffee grounds are actually used on spider plants, as there are a few different methods for doing this.
Liquid Fertilizer
If you place a few cups of coffee grounds in water and leave it for a day or two you’ll create a nutrient-rich liquid fertilizer that can be used as a spray or directly when watering your spider plant.
Compost
Using coffee grounds to boost a compost heap will produce a great fertilizer rich in a variety of nutrients that can be added to the soil of your spider plant.
In my opinion, this is the best way to utilise coffee grounds for a spider plant.
Directly Into Soil
Coffee grounds can be added directly to the soil of your spider plant, but you’ll need to mix them in or they can cause a hydrophobic layer that will repel water and dry out the soil below.
Arguments For Using Coffee Grounds On Spider Plants
Coffee grounds are popular for houseplants for a reason; they do bring a lot of benefits to the table.
Nitrogen (And Other Nutrients)
Coffee grounds contain around 2% nitrogen by volume, as well as other nutrients in smaller amounts such as calcium, potassium and magnesium.
Nitrogen is responsible mainly for leaf growth in spider plants, so coffee grounds are beneficial for making your spider plant look bushier by promoting new leaf growth and developing existing leaves.
Add To Compost To Boost Potting Soil Mix
The nitrogen found in coffee grounds is super useful for boosting the composting process.
So, you can add coffee grounds directly to your compost heap, and once the compost is ready this can be added to the soil mix of your spider plant.
Keep the amount of compost to around 10-25% of the total mix and use other ingredients such as peat moss and perlite to improve the drainage and nutrient profile further.
Less Waste
Utilizing coffee grounds after you’ve brewed your morning coffee is a great way to reduce the overall waste that you produce.
Coffee grounds can emit a lot of methane when they decompose, so it’s something to think about if you get through a lot of coffee each week as I do.
Arguments Against Using Coffee Grounds On Spider Plants
It’s crucial to understand the negatives of using coffee grounds before you jump right into using them on your spider plant.
Small Overall Amount Of Nutrients
The nitrogen content of coffee grounds might be significant, but it lacks other key nutrients that spider plants need to thrive.
A complete fertilizer, which is ideal for spider plants, contains nitrogen, phosphorus and potassium (NPK). All three nutrients are required in significant amounts to ensure spider plants can grow properly.
Since coffee grounds only have significant amounts of nitrogen, it can become easy to neglect other nutrients if you rely only on coffee grounds to fertilize your spider plant. This can lead to nutrient imbalances further down the line.
Root Rot
Using coffee grounds as a liquid fertilizer can lead to overwatering quite quickly if you aren’t reducing the amount of regular water that you provide.
In serious cases, this can lead to root rot, which can potentially kill a spider plant if it isn’t dealt with.
Pests
Another problem that liquid coffee ground fertilizer can cause is similar to that with misting houseplants – the excess moisture can attract pests such as spider mites and aphids.
If you decide to use liquid fertilizer I would highly recommend only using it for watering and not misting. I would regularly check the soil to make sure you aren’t overwatering.
Are Coffee Grounds Too Acidic For Spider Plants?
Used coffee grounds are only slightly acidic, and since spider plants prefer slightly acidic soil with a pH between 6 and 6.5, there is nothing to worry about in this regard.
My Opinion
I have experimented with coffee grounds in the past on a variety of houseplants, including spider plants, and it hasn’t worked particularly well for me.
As a coffee addict, I can see the appeal of using the grounds for something when you’re done with them, and if I had a compost heap I would definitely add my coffee grounds to it without a doubt.
However, adding coffee grounds directly to the soil or via a spray seems to not have a big effect. It can also become an issue if you rely too heavily on just coffee grounds to provide nutrients, and can attract fungus and insects as well.
In the end, the decision is up to you. Coffee grounds can provide some key nutrients to plants but in very small amounts, and they’re only likely to provide significant amounts of nitrogen.
