We have several fruit trees from lemons to figs, and it’s the time of year to start fertilizing them. The only problem is, we usually have only two options: use chemical fertilizer or use manure. But what about the in-between? Is there a way we can fertilize a garden or indoor fruit trees without using chemicals or stinky manure? And even better, can we use kitchen scraps and yard waste to do it? I did some research to find out more.
Homemade fruit tree fertilizer can be made from everyday kitchen and yard scraps such as coffee grounds, banana peels, and grass clippings. Ideally, fruit tree fertilizer should have high amounts of nitrogen, followed by phosphorus and potassium. Most ingredients will also provide plenty of secondary nutrients.
So, while homemade fertilizers can provide well for fruit trees and even replace chemical fertilizers, what exactly should be in them, and what are some example combinations we can use? Let’s take a closer look.
What Should Be in Homemade Fruit Tree Fertilizer?
Fruit tree fertilizer that’s homemade should have plenty of nitrogen, phosphorus, and potassium. This is often achieved by using enough “green” compostables such as grass clippings, coffee grounds, and bone meal. While the ingredients will vary in nutrients, you can tailor your own mixture to best suit the tree.
One of the biggest goals when making your own homemade fruit tree fertilizer is achieving a high NPK, or nitrogen, phosphorus, and potassium content. These are the three main ingredients for pretty much any plant and they’re key in everything from the growth of the foliage to blossoms and fruits. Without sufficient nutrients, fruit trees will become stressed and commonly shed their fruit, blossoms, and leaves, often in that order.
Fortunately, many kitchen and yard scraps contain plenty of primary nutrients, along with a variety of secondary, or minor nutrients.
To help illustrate this, here are some of the key nutrients to keep in mind when making homemade fruit tree fertilizer (you don’t need to remember them all, just the main ones).
How to Make Fruit Tree Fertilizer at Home
Now that we have a good idea of the nutrients fruit trees need, let’s take a look at some of the most common kitchen and yard scraps that can provide them.
To help answer this, I spent some time researching and putting together the table below as a resource, so you can quickly learn how to make your own fruit tree fertilizer at home.
|Nitrogen||Grass trimmings, green leaves, coffee grounds||Overall growth|
|Phosphorus||Bonemeal, gelatin, leaves||Roots and blossoms|
|Potassium||Banana peels, orange peels, sweet potatoes, mushrooms, cucumbers||Overall growth, hardiness, water retention|
|Sulfur||Leaves, onion skin, broccoli stems, asparagus stalks, beans||Enzymes and proteins|
|Calcium||Eggshells, kelp, blackstrap molasses, orange peels, bonemeal||Disease resistance, pH, healthy cells|
|Iron||Kelp, blackstrap molasses, beans, spinach, cacao powder||Chlorophyll, enzymes|
|Zinc||Seaweed, potatoes, mushrooms, broccoli stems, spinach, beans||Chlorophyll, energy, cold resistance|
|Magnesium||Epsom salts, banana peels, kelp, blackstrap molasses, eggshells||Overall plant growth, photosynthesis|
|Copper||Sweet potato skins, mushrooms, leafy greens, cacao powder||Enzymes, photosynthesis, respiration, energy|
|Manganese||Pineapple cores, banana peels, grains, beans, cacao powder, beets||Photosynthesis, respiration, pollination, roots|
|Chlorine||Seaweed, ryegrass, tomatoes, lettuce, celery||Overall growth (use in very small amounts)|
|Boron||Apple cores, carrots, apricots, celery, honey||Energy, healthy cells, pollination, seeds|
Remember, don’t stress too much about including all of these items. You don’t need to hit every nutrient listed as there’s a lot of overlap and many ingredients will contain trace amounts of other nutrients and minerals. This list primarily serves as ideas for food and yard waste you might already have available at home.
If you’re still feeling overwhelmed, let’s take a look at some of the most important nutrients and some example combinations you can use for your fruit trees.
Simple Homemade Fruit Fertilizer
A lot of the above ingredients have many different nutrients in them, so it’s hard to get homemade fertilizer wrong. Most of the time, as long as you’re providing enough of the main nutrients (nitrogen, phosphorus, and potassium), your fruit tree will receive trace amounts of other nutrients and remain healthy.
However, if you’d still like some recommendations for fertilizer combinations, you’re in luck. Here are some example fertilizer combinations.
- Green leaves
- Grass clippings
- Banana peels
- Coffee grounds
- Banana or orange peels
All of these combinations will make a good homemade fertilizer for your fruit trees. The grass, green leaves (prunings), and coffee grounds will provide high amounts of nitrogen, while the bonemeal, eggshells, banana, and kelp provide healthy amounts of phosphorus and potassium.
Remember that most fruit trees require more nitrogen than phosphorus and potassium, so make sure to do a quick search to determine which NPK your specific fruit tree likes. For example, citrus trees prefer a 2:1:1 NPK ratio, or twice the nitrogen to phosphorus and potassium.
While the above ratio can be hard to measure for homemade fertilizer, you can use 65-75% grass clippings, coffee grounds, and other high nitrogen ingredients, and 25-35% phosphorus and potassium (like bonemeal and banana peels). This should help make sure the NPK ratio is fairly approximate and you’re not going over on any one nutrient.
Sometimes, you can even tailor your homemade fertilizer to help treat certain fruit tree conditions. For example, yellow leaves can sometimes mean a lack of nitrogen or iron, while dropping fruit can benefit from extra magnesium.
So, while these are some easy ways to make your own homemade fruit tree fertilizer, what makes it so different than just buying store-bought fertilizers?
The Differences Between Synthetic and Homemade Fertilizer
Synthetic and chemical fertilizers are largely derived from fossil fuels, which are the same materials as plastic. These fertilizers interrupt the nutrient trade between the soil and trees, which damages ecosystems. Homemade fertilizers are made from organic materials that decompose and assist plant growth naturally.
The problem with our current options for fruit tree fertilizer is that we really get two main choices: chemical fertilizers and manure.
Typically, chemical fertilizers are used in conventional farming as it’s a seemingly effective choice (often at the detriment of the long-term health of fruit trees and the soil), while manure is the go-to option for large-scale organic farming.
“Approximately 70-80% of nitrogen (N), 60-85% of phosphorus (P), and 80-90% of potassium (K) found in feeds is excreted in the manure. These nutrients can replace fertilizer needed for pasture or crop growth, eliminating the need to purchase fertilizers. Plants do not distinguish between sources of nutrients. However, compared to commercial fertilizer, manure contains organic carbon which is the key to maintaining soil health, including the characteristics of cation exchange capacity, soil tilth, and water holding capacity.”University of Massachusetts Amherst
I don’t know about you, but I don’t want my backyard to have poor soil, or smell like manure, so there has to be another way, right?
This is where homemade fruit tree fertilizer, and compost, come in to play.
By creating your own fruit tree fertilizer, you’re reusing and providing valuable nutrients for your fruit trees that would otherwise end up in landfills and ironically—doesn’t decompose since it’s layered in-between plastic.
Along with homemade fertilizer, compost is another popular choice for plants since it has an amazing collection of decomposed nutrients that are immediately available to be absorbed by the fruit tree’s feeder roots.
If you’d like more information about the differences between manure and chemical fertilizers, you can check out my recent post: Is Manure Good for Fruit Trees? If So, Which Ones Are Best?
When and How Often Do You Use Homemade Fruit Tree Fertilizer?
Homemade fertilizers should be applied 1-2 times per growing season. If desired, compost can also be used with this same frequency. On the other hand, most fast-releasing chemical fertilizers need to be applied every 1-2 months, while slow-releasing chemical fertilizers are applied 1-2 times per year.
Generally, the growing season for most fruit trees starts in the early spring, but some fruit trees start growing and fruiting later in the year. For best results, check your fruit tree’s specific growing season and aim to provide your fertilizer at the start of it (or after the last frost).
The reason why we shouldn’t be providing fruit trees with fertilizer in the off-season is that most fruit trees (such as apple and cherry trees) go dormant. During this time, they’re conserving energy to survive the winter and don’t use as many nutrients in the soil. In fact, too many nutrients that are sitting for too long can chemically burn their roots and damage the tree’s growth.
So, now that we know when and how often to use homemade fertilizer on our fruit trees, how exactly should we be applying it?
How Do You Apply Homemade Fruit Tree Fertilizer?
You can apply your homemade fruit tree fertilizer by either burying it under the first 1-2 inches of soil or composting it first. Since fruit trees typically have shallow roots and the soil shouldn’t be disturbed, compost is the better option. You can use 1-2 inches or 1-5 pounds of fertilizer or compost.
While I used to dig a small hole around the drip line of my fruit trees and bury some food scraps (like in the image above), I later found that this typically isn’t the best practice. The reason is that most fruit trees have shallow roots, with 90% of them located in the first 2 feet of soil. These shallow roots can easily be damaged and stunt the fruit tree’s growth.
Not only that, but I learned that digging and tilling soil disturbs the soil life, including the all-important fungal, or mycelium layer.
So, while burying your homemade fertilizer around the drip line of your fruit trees is fine (it worked for me), letting it compost first and then applying it on top of your fruit tree’s soil is the better approach.
Composting the Ingredients
For best results, provide 1-2 inches of your compost on top of the soil within the drip line of your fruit tree. Keep it at least 3 inches away from the tree’s trunk to prevent mold or disease. Apply 1-2 inches of mulch on top of the compost to protect it from the elements and help it retain moisture.
When mulching, you can use garden waste such as bark, wood chips, or leaves. If you currently throw out your leaves, you should seriously reconsider.
Also, if you’re new to composting, don’t worry! It’s fairly simple and can be fun. An easy way to get started is with a worm bin, and you can even do this in apartments! In fact, that’s how I started.
Worm composting is also much faster than traditional composting. Hot composting (keeping the pile above 135ºF) can take a few weeks to break down food scraps, while cold composting can take up to a year! On the other hand, worm composting (also called vermicomposting) can take as little as a couple of weeks. Worms also leave behind worm castings, which are potent, organic nutrients that are great for fruit trees.
If you’re ready to get started on a worm bin, you can check out my short video below that shows how I set up my worm bin for $19 and in 5 minutes. You can also reference my recent post: The 6 Best Worms for Composting.
Can You Apply Too Much Homemade Fertilizer?
It’s hard to apply too much homemade fertilizer since it’s mostly organic matter. Because there’s a mix of nutrients, and they’re not typically potent, you should be safe applying the suggested 1-5 pounds seasonally.
However, just like synthetic fertilizer, if you’re using any sort of nutrient concentrate, it’s best to dilute or disperse it. For example, Epsom salts should be dissolved in water before applying. A good ratio is 1-2 tablespoons per gallon of water.
Most other ingredients like food scraps and bonemeal don’t need to be dispersed, but it can benefit the plant if you at least mix them with the other ingredients to help provide balance.
If you’re concerned about the concentration of your fertilizer, you can always dilute it in water, and apply it, similar to the Epsom salts above, or compost tea.
Lastly, if you’re growing your fruit tree in a pot, consider using 1-2 pounds per growing season instead, as there’s a limited amount of soil to worth with and nutrients won’t run off as much as planted trees.
More Homemade Fertilizer Tips
If you’re looking for a good nitrogen supplement for your fruit trees, coffee grounds are nearly perfect. Fruit trees typically prefer lots of nitrogen and slightly acidic soil pH, both of which coffee provides. For best results, use dried coffee grounds, as wet grounds can often clump up and create mold.
Eggshells provide a high amount of calcium and magnesium but should be dried and ground for the best application. You can bake the eggshells on the sheet at 200ºF for 30 minutes or until completely dry and then grind in a blender.
If you don’t have time to concoct a mix of kitchen or yard waste, you can always apply 1-2 inches of compost on top of the soil for a good balance of nutrients. Just make sure to keep it at least 3 inches away from the trunk.
Blackstrap molasses might seem like an odd choice for homemade fertilizer, but it contains a lot of nutrients and the sugar helps beneficial bacteria in the soil develop. If you’re using blackstrap molasses, a good ratio is 1 teaspoon per gallon of water and apply generously.
While wood ash makes for a good fertilizer for some plants, it shouldn’t be used for most fruit trees. This is because fruit trees typically prefer soil pH around 6.0-7.0, which is slightly acidic. On the other hand, wood ash has high alkalinity with a pH of 9-11. When the pH is thrown off, the fruit tree will have a hard time absorbing the proper nutrients. The same goes for charcoal or biochar.
If you don’t have bonemeal readily available, you can always use unflavored Jello (gelatin) as a replacement. Simply dissolve 1 pack in 1 cup of hot water and then add 3 cups cold water. However, there are often additives in the package, so keep this in mind and don’t use it too often.
If you’re also interested in making your own homemade fruit tree potting soil, I spent several hours researching the best soil combinations to use for potted citrus trees. These potting mixtures can also be used for many other fruit trees such as avocado, mango, banana, so make sure to check it out!