We’ve been composting for awhile here at the Farmhouse (see my composting set up here). I love being able to hang onto kitchen waste for a higher purpose. Some scraps go as treats to the chickens and parrot, while others go into a special compartment in our freezer (so they don’t attract flies) before being taken outside to the compost bins. But I was unaware until recently that certain scraps, mainly eggshells, used coffee grounds, and banana peels, can allegedly go straight into the ground as fertilizers.
There are a ton (okay, slight exaggeration) of these three things going into our compost bins, and so when I realized that they could possibly skip the bin and be applied straight, I got real excited. Because these are the things I get excited about. What.
So I broke out good ol’ Google, and I started doing some research. And just like anything that you hear going around the internet, I came up with really mixed messages. Allegedly, coffee grounds add nitrogen to the soil, and as such, are great as fertilizer for any acid-loving plants. But you’ll find people out there also warning you that they can make the ground too acidic. And you’ll find people saying they do absolutely nothing. Great. Banana peels, buried in the soil near the roots of the plant (or dried and processed into a fine powder), are thought to be a slow-release dose of potassium and phosphorus, as well as magnesium, calcium, nitrogen, and sulfur, and are especially perfect as a rose fertilizer. In fact, banana peels have been used as such since the Victorian era. And yet, you’ll also find people saying they do absolutely nothing. And that the garden rodents dig ’em real quick-like. Super. Finally, ground eggshells mixed into the soil around a tomato plant are supposed to prevent the dreaded blossom end-rot. But there are a lot of people who say this doesn’t even begin to work (that the calcium carbonate in egg shells takes so long to break down and be released into the soil, it’s just not worth it). Fantastic. Furthermore, it’s nearly impossible to find anyone committing to how much of any of these ingredients you should add to your soil. Which is frustrating, and also a bit suspicious. Is this all just wives’-tale-ery?
So what do I do? Test it for myself, that’s what.
Let’s start with adding eggshells to the tomato planting process. Tomatoes need calcium in order to resist blossom end-rot, and there are many conventional products on the market that can be added to combat this. But I don’t want conventional. I want to use my garbage. I’ve got a lot. The Ladybirds make sure of that. And you need a lot of eggshells for this (depending on how many tomato plants you’ve got or plan to have). As you use the eggs, rinse and then store the shells in a bowl in the fridge. I saved up about two dozen for this first trial run.
When you’re ready to process them, heat your oven to 200-250 degrees F and bake them in a baking pan for around 30 minutes (or until all the moisture is cooked off of them. If they start to brown a little, that’s ok). When the time is up, pull them from the oven and let cool. Now pop them in a food processor (or coffee grinder) and pulverize them into as fine of a powder as you can get them. The finer the powder, the quicker the calcium will break down in the soil. Apparently.
Your (hopefully) magic egg dust is ready to use! Allegedly, the most ideal time to use it is when you transplant your seedlings; you place it in the bottom of the hole. But here’s where I could find no information on just how much you are supposed to use. So I am going out on a limb and trying several different quantities to see if there is any variation in results. In a few of my plants, I will use 1/4 of a cup sprinkled in to the bottom of the transplant hole, for a 4-inch pot sized seedling, in a few I will do 1/2 cup, and in a few more I will try 3/4 cup . I will report back on how this works; in previous years, I have always had a few plants suffering from blossom end rot–so we shall see how things go this season.
So let’s move on to coffee grounds; acid-loving plants, such as hydrangeas, camelias, and azaleas can benefit from the application of coffee grounds. Even for plants that like it a little acidic, such as roses and tomatoes, they can be used sparingly. Supposedly, worms love them (and they’re great for adding to vermicompost). But…of course, when you start reading all the information out there about this, you undoubtedly run into the same cautionary tale: coffee grounds are great, but don’t use too much! Dear Zeus, no! Not that! And then, beyond that, there are plenty of accounts of how they do nothing at all. Great. Awesome. So how much is too much? Of course, no one wants to commit to this, and just like the eggshells, there are no quantity guidelines. Super. Thanks, The Internet.
So once again, I must go my own way. While I allow a good portion of our grinds to go out and into the compost bins, I reserve some in a bowl in the fridge. When I’ve filled the bowl (approx. 8 or so cups of used grounds), I place them in a baking dish and pop them in the oven (alongside the eggshells) for a half hour at 200-250 degrees F to dry them out. The reason for this is that damp grounds have a tendency to grow mold pretty quickly and this helps to prevent it.
It seems as though there are several methods out there for applying the grinds. Many people will make a mulch of it around their acid-loving plants (and the thicker this is, the more likely it is to grow mold, so go thin with it). But if you’ve got chickens, this is not a good idea. Coffee grounds=sick chickens. So I prefer the idea of burying them pretty deep down by the roots of the plants–we’re talking several inches here. How much coffee grounds? Again, I have found no direction with this. For my rose bushes, I decided, at random, that I’d go with 1/4 cup to 1/2 cup, buried in a hole near the roots. My hydrangeas are all in the front yard, and therefore, out of the reach of chickens, so I’ve been applying coffee grounds as a mulch basically whenever I have them. I should also mention that I take any leftover coffee and, after it has cooled off, water my hydrangea bushes with it. So, they are pretty much coffee addicts at this point. In previous years, my hydrangeas have been pink, indicating the soil being neutral to basic–if the coffee grounds do their trick, the hydrangeas should become more purple to blue. They are leafing out now, so I’ll have my answer soon.
Finally, we come to the banana peels.
As I mentioned before, banana peels have been used as a rose fertilizer for a long, long time. Burying a single banana peel at the base of the plant is the simplest way to do this. As the peel decomposes, it releases nutrients into the soil; nutrients that roses, especially, are said to thrive upon. Some people suggest drying the peels and grinding them into a fine powder (to speed up the absorption process), but I feel like that’s a lot of extra work. So I went with the peel.
Of course, truly the only way to be sure of what’s going on in your soil is to do a soil test. I really want to know if these methods work, so I tested my soil in each spot before application, and I will test again in a couple of weeks and see if there is any change, and then I’ll come back through and report my findings in this post.
I should note that over-the-counter calcium tests are not super easy to come by, that I know of– so I’m probably just going to sit around and wait to see if I still get blossom end-rot. The tomatoes. Not me. In related news: does anyone know of an easy calcium test?
I’m curious to hear from anyone else who has tried these fertilizers; please comment and let me know your experience!