Foliar Feeding With Calcium: How To Make Your Own Calcium Fertilizer

DIY Calcium Fertilizer In Plastic Jar
calcium water
(Image credit: Gardening Know How)

Foliar feeding with calcium (the application of calcium rich fertilizer to the plants leaves) may make the difference between a bumper crop of tomatoes to fruit with blossom end rot, or gorgeous Granny Smith apples to bitter ones. Let's learn more about making and using a calcium foliar spray on plants.

Why Use Homemade Calcium Rich Foliar Spray?

Calcium foliar spray lends necessary calcium to the plant, preventing leaf necrosis, short brown roots, fungal issues, weak stems and stunted growth (damping off). Making calcium spray for plants will increase cell division, an important component, especially in those rapid growers such as tomatoes, sweet potatoes, and corn. While it is true that acidic soils have a reduced amount of calcium compared to more alkaline soils, pH is not a true reflection of the necessity for foliar feeding with calcium but may be used as a general guideline.

Homemade Calcium Rich Foliar Spray

While commercial calcium foliar sprays may be purchased, it may be less expensive and just as easy to make a homemade calcium rich foliar spray with ingredients already in the home or garden. If you are experiencing any of the plant symptoms above or have had your soil's pH tested and it's deficient in calcium, now is a good time to learn how to make your own calcium fertilizer.

Foliar Feeding with Calcium Rich Eggshells

Plants require a ratio of calcium and magnesium; when one goes up, the other goes down. Utilizing your compost, which is generally rich in calcium or can be amended with the addition of lime or eggshells, is one way to increase the calcium level in growing plants. Another way to accomplish this goal is by making calcium spray for plants with eggshells. To make calcium spray for plants with eggshells, boil 20 eggs in a pan covered with 1 gallon (3.6 kg.) of water. Bring to a rolling boil, then remove from heat and allow to cool for 24 hours. Strain the water of shell fragments and store in an airtight container in a cool, dark place. Another way to make homemade calcium rich foliar spray is by filling a gallon (3.6 kg.) jar with water and eggshells. Steep for one month, allowing the eggshells to dissolve and filter their essential nutrients into the liquid. To create your calcium foliar spray, mix 1 cup (454 gr.) of the resulting solution with 1 quart (907 gr.) of water and transfer to a spray bottle. This homemade calcium rich foliar spray is also rife with nitrogen and magnesium, phosphorus and collagen, which are all essential nutrients for healthy growth.

Foliar Feeding with Calcium Rich Seaweed

It's not just for sushi anymore. Particularly rich in bromine and iodine, seaweed is also rich in nitrogen, iron, sodium and calcium! So, how to make your own calcium fertilizer out of seaweed? Collect the seaweed (if legal to do so where you are) or buy at the garden store and rinse thoroughly. Chop up the seaweed and cover with 2 gallons (7.6 L.) of water in a bucket. Cover loosely, ferment for a few weeks, and then strain. Dilute 2/3 cup (158 ml.) to one gallon (3.8 L.) of water to make a calcium foliar spray.

How to Make Your Own Calcium Fertilizer Out of Chamomile

Chamomile contains sources of calcium, potash, and sulfur, and as such is good for preventing damping off and many other fungal issues. Pour 2 cups (473 ml.) of boiling water over ¼ cup (59 ml.) chamomile blossoms (or you can use chamomile tea). Let steep until cool, strain, and place in spray bottle. This foliar solution will keep for one week.

Other Methods for Making Calcium Spray for Plants

Great for any number of things, Epsom salts contain magnesium and sulfur, and where there's magnesium there is certainly a correlation to calcium. The magnesium content aids the plant in utilizing other nutrients, such as calcium, more effectively. Plants, such as roses, tomatoes, and peppers, which require higher amounts of magnesium, benefit the most from this spray. The general recipe for using Epsom salt as a calcium foliar spray is 2 tbsp. salts (30 ml.) to 1 gallon (3.8 L.) of water, but for the aforementioned, cut the Epsom salt to 1 tbsp (15 ml.) to 1 gallon (3.8 L.) of water. Antitranspirants can be used in the amount of ½ tsp (2.5 ml.) to 8 ounces (237 ml.) of skim milk (or equal amount of prepared powdered milk) for foliar feeding with calcium. Antitranspirants can be purchased via a garden center and are usually made from natural oils such as those from pine trees. Be sure to flush the sprayer out with water when done. Last but not least, I previously mentioned using one's compost to enrich soils with nutrients. Compost tea can be made with one part of mature compost to two parts of water (this can be done with mulched weeds, herbs, or pond weeds too). Let sit for about a week or two and then strain and dilute with water until it looks like a weak cup of tea. This makes a fine method of foliar feeding with calcium. BEFORE USING ANY HOMEMADE MIX: It should be noted that anytime you use a home mix, you should always test it out on a small portion of the plant first to make sure that it will not harm the plant. Also, avoid using any bleach-based soaps or detergents on plants since this can be harmful to plants. In addition, it is important that a home mixture never be applied to any plant on a hot or brightly sunny day, as this will quickly lead to burning of the plant and its ultimate demise.

Amy Grant

Amy Grant has been gardening for 30 years and writing for 15. A professional chef and caterer, Amy's area of expertise is culinary gardening.