Many gardeners love growing strawberries in the Spring and Summer because they are relatively easy to grow, and have a sweet payoff. If your soil isn’t healthy though, you could be biting into a bitter berry after providing months of TLC for your strawberry plants. Strawberries love nitrogen-rich soil and planting your strawberries directly into the unprepared ground, or nutrient-devoid soil simply won’t do the trick. However, you might be able to skip an extra trip to the gardening store to pick up some fertilizer, by just using one of the most commonly discarded food products, eggshells. So do eggshells really work to provide nutrients and help grow your strawberry plants? Keep reading to find out!
How to care for strawberries
While strawberries are a relatively simple crop to grow, they still have specific needs in order to get the best harvest. Strawberries require full sun, slightly acidic to neutral soil[1], and lots of water, and they thrive with added fertilizer. Make sure to plant your strawberries where they will get lots of sun, and keep the soil moist, especially during the hotter months. Giving your strawberry plants the perfect soil however can be a bit more complicated, especially if you are planting your strawberries into the ground rather than in pots, or raised beds. Strawberry plants need well-drained soil that has a pH between 5.5 and 7[1]. Well-draining soil will make sure your plants don’t become overwatered. In addition, growing plants, especially seedlings and young plants need plenty of calcium to grow strong healthy roots.
Are eggshells a good fertilizer?
You have to crack a few eggs to make a good fertilizer. Luckily, in this case, that’s a good thing. You can have your omelet and eat it too, and eliminate food waste in the process. Eggshells are made up mostly of calcium carbonate, the “ingredient found in agricultural lime”[4]. Agricultural lime is used to improve the soil as well as enhance the properties of other fertilizers. A study conducted by Jeff Gillman, the author of “The Truth About Gardening” found that an eggshell soaked in water for 24 hours would produce “4 mg of calcium and potassium, as well as very small amounts of phosphorus, magnesium, and sodium”[4]. In comparison, agricultural lime is made up of about 40% calcium. So, it may take quite a few eggshells to get the same properties as agricultural lime, but it is a natural, and almost free way to add some extra nutrients into your soil.
The use of eggshells in gardening is primarily to infuse extra calcium. Plants like strawberries need calcium to grow, as it helps plants “develop a strong cellular structure”[4], especially young plants. Calcium deficiency in plants can lead to stunted growth, the death of roots, and can lead to “a general collapse of membrane and cell wall structure…since there is broken down and dead tissue in these areas, microbial infection frequently results”[5]. Calcium, therefore, is essential in the healthy growth of fruits and vegetables in the garden. Eggshells, therefore, are a great addition to the garden for some added nutrition, however, eggshells alone won’t make up entirely for other deficiencies. Your strawberry plants still need adequate water, plenty of sun, and nutrient-rich soil, not just calcium-rich. If your strawberry plants are neglected, sprinkling a little eggshell won’t be putting out any fires.
Eggshells aren’t the perfect fertilizer, but they certainly help. Calcium is especially important for the growth of young and rooting plants, so it definitely can’t hurt to add some eggshell fertilizer. Ground eggshells also deter pests like slugs and snails, as the “sharp edge of the shells irritate the soft bodies of the slugs”[4], so even if eggshells aren’t the perfect fertilizer they can certainly aid with other issues.
How to make eggshell fertilizer
Making eggshells fertilizer is super easy, and practically free. Eggshells can deter pests, aids in nutrient absorption, and encourages root growth. Depending on your garden’s needs, it is a great addition to your soil. There are a few easy ways you can make eggshell fertilizer depending on what tools you have at your disposal.
1. Crushed eggshell fertilizer
Pretty self-explanatory, this method involves simply crushed eggshells. First, wash your eggshells with plain old water to remove any egg membrane and residue. Once your eggshells are clean, leave them to dry completely. Once your eggshells are dry, you can crush them with a mortar and pestle, or you can throw your eggshells in a Ziploc bag and crush them with a rolling pin or glass bottle. Mix this in with your soil or sprinkle it on top of your garden or potted plants to add that extra kick.
2. Ground eggshell fertilizer
You can also grind eggshells using a food processor or coffee grinder. First, clean your eggshells with clean water until they are free of any residue. Allow the eggshells to dry completely and then throw them in your food processor or coffee grinder. You can add eggshells to other compost to make a mulch or fertilizer, or mix it in with your soil. You can sprinkle it directly into your garden and pots, or even into your planting holes when planting seeds.
3. Eggshell tea fertilizer
You can also make an eggshell fertilizer tea by boiling eggshells. A liquid fertilizer tea will quickly and deeply penetrate the soil giving quick nutrition to your plant’s roots. Start by cleaning your eggshells with water. and then let them dry. Next, boil a gallon of water and add 10 to 20 egg shells[2]. Remove the water from the heat and leave your eggshells to soak in the hot water overnight. The next day, strain your eggshells and save the water. You can add up to 2 cups of eggshell fertilizer tea to each of your plants[2], being sure not to overwater your plants.
Does eggshell fertilizer work for strawberries?
Yes, adding eggshells to your strawberry garden will certainly help. Calcium can help your strawberry plants grow stronger and better, along with many other plants. In order for your plants to get the most nutrients from your eggshells, you should finely grind them, or make an eggshell tea. If you need to deter pests like snails and slugs, you can leave larger bits of shell on the surface of the soil, but your plants won’t absorb many nutrients from these. In fact, “finely ground eggshells perform at least as well as pure calcium and agricultural lime”[3] at providing calcium in your soil.
While eggshells are brilliant at providing the much-needed calcium for your plants, they won’t save your plants on their own. Your strawberry plants will still need plenty of sun and water, the soil at a specific pH level, and plenty of nitrogen as well. Nitrogen-rich fertilizer in combination with the calcium from eggshells can definitely make your strawberry plants stronger, and yield more berries at harvest time. Nitrogen-rich fertilizer should be applied to your garden after the first harvest of the year. If nitrogen-rich fertilizer is applied too early it can result in softer berries[3]. The addition of nitrogen-rich fertilizer in combination with the calcium from ground eggshells can help your strawberry plant’s fruit production multiply.
If you’re looking to use up even more food waste in your garden, coffee friends are an excellent natural source of nitrogen. Coffee grinds also help the slightly acidic soil levels that strawberry plants love so much. Just like fertilizer, you should only add coffee grounds to the garden after the first harvest of the year. Mix coffee grounds into the soil after the first harvest without leaving any coffee grounds to sit on the surface, as this can repel water. The coffee grinds will also deter soft-bodied pests like slugs and snails. To make sure your soil is at a good pH level you can use a pH soil testing kit.
In short, eggshells are great for your strawberry plants, but they won’t make up for other shortcomings. Make sure to finely grind your eggshells if you want to get the most calcium possible, and leave them coarser ground to deter pests. Your strawberries will need plenty of sun and water, so plant them accordingly. Strawberry plants also thrive in slightly acidic soil and nitrogen-rich fertilizer. Coffee grinds are another great addition to the garden to increase the pH and nitrogen levels in the soil.
Article Sources:
- Almanac. “Strawberries“
- MasterClass. “Egg Shell Fertilizer: 4 Benefits of Eggshell Fertilizer“
- PH & G. “How to Make Strawberry Plants Produce More Fruit [8 Tips]“
- SFGATE. “Homemade Eggshell Plant Fertilizer“
- UC ANR. “Calcium Deficiency in Strawberry“