While it’s easy to pick up pre-made plant fertilizer from your local garden center, making your own from household items can save money and let you control exactly what goes into it.
First, let’s break down the nutrients that plants need from the soil—also known as mineral nutrients. (Plants get non-mineral nutrients like hydrogen, carbon, and oxygen from air and water.) Mineral nutrients are divided into two categories: macronutrients and micronutrients. The key macronutrients plants need are nitrogen, phosphorus, and potassium. In addition, plants require secondary macronutrients like calcium, magnesium, and sulfur. Most commercial fertilizers contain a balanced mix of these primary nutrients to promote healthy growth. When making your own fertilizer, you’re aiming to replicate this balance.
Before you start, it’s crucial to test your soil to see what nutrients it already contains. (Not sure how to test? You can either purchase a soil testing kit or follow a simple DIY method.) The results will guide you in adjusting your homemade fertilizer to meet your garden’s specific needs. For instance, if your soil lacks potassium, adding banana peels to your compost might help. (We’ll cover that more in a bit.)
It’s also important to check your soil’s pH, as the availability of key nutrients depends on the soil’s acidity or alkalinity. The ideal pH for most plants is between 6.0 and 7.0. If your soil’s pH is too low (acidic), you can add lime to raise it. If it’s too high (alkaline), sulfur can help bring it down. In a neutral pH range, plants are able to absorb nitrogen more efficiently, which leads to healthier growth.
Knowing your soil’s composition and pH level is the first step to creating a nutrient-rich homemade fertilizer. Once you’ve got that information, here are some key ingredients you can try adding to your DIY mix:
Banana Peels
Just like bananas are a great source of potassium for humans, they can be a powerful tool for plant growth as well. Banana peels are particularly useful in the garden, especially for roses. There are various ways to utilize banana peels in your garden, such as composting them or directly placing them in the soil to boost potassium levels.
Compost
If you haven’t already, consider starting a compost pile. Composting involves combining green matter (like food scraps) and brown matter (such as dead leaves and sticks) with water to break down organic materials. Over time, this creates nutrient-rich compost that can be spread around the base of plants to help retain moisture and enrich the soil with essential nutrients.
Coffee Grounds
Both fresh and used coffee grounds can be beneficial for your plants. Fresh coffee grounds, which are more acidic, can be used on plants that prefer acidic soil, such as azaleas, hydrangeas, and lilies, as well as root vegetables like carrots and radishes. Used coffee grounds, on the other hand, are less acidic and can be added to your compost pile to provide nitrogen and aid in decomposition.
Eggshells
Crushed eggshells offer an excellent source of calcium for your plants. Simply wash the shells, crush them into a fine powder, and sprinkle it around the base of your plants to strengthen their cell structure.
Epsom Salts
Epsom salts, made from magnesium sulfate, have been used for years to improve plant health. Magnesium is essential for seed germination, chlorophyll production, and the absorption of nutrients like nitrogen and phosphorus. Adding Epsom salts to your garden can enhance plant growth by strengthening cell walls and boosting nutrient uptake.
Urine
Believe it or not, diluted urine can be an effective fertilizer due to its rich nutrient content. Since urine is highly concentrated, it’s important to dilute it before applying to avoid damaging your plants. A good rule of thumb is to mix one cup of urine with 20 cups of water and pour it around the base of your plants.
Beer
Yes, you read that right—beer! This common household beverage contains fermented malt and hops, which are rich in amino acids and provide a weakly acidic, nutrient-filled solution that can benefit your plants. But be careful not to pour it directly onto the soil. To use beer as a plant booster, dilute it with water at a ratio of 1 part beer to 10 parts water. This mixture can be used to water the roots or even mist the leaves. You can also mix beer with water at a ratio of 1:30 to wipe down plant leaves, which works great for plants like Monstera, Fiddle Leaf Fig, and Pothos.
This natural approach to gardening not only helps your plants thrive but also keeps your wallet happy!