How to naturally increase soil calcium for tomatoes?
Written by
Tina Carter
Reviewed by
Prof. Charles Hartman, Ph.D.A natural way to prevent a calcium deficiency issue when growing tomatoes is by enhancing the soil calcium level naturally, without the use of synthetic chemicals. Organic amendments improve the structure of soils and provide important nutrients. In this guide, we will focus on four effective natural sources of calcium: eggshells, gypsum, bone meal, and dolomitic lime. Each provides calcium but operates in a distinct manner suited to different soil conditions.
Crushed Eggshells
- Require 6-24 months decomposition to release calcium carbonate
- Best incorporated during fall soil preparation
- Apply 1 pound per 10 square feet for moderate deficiency
Agricultural Gypsum
- Provides immediate calcium sulfate without altering pH
- Ideal for heavy clay soils needing structure improvement
- Apply 2 pounds per 100 square feet before planting
Bone Meal
- Organic phosphorus-calcium blend from animal bones
- Works best in neutral to alkaline soils
- Use 5 pounds per 100 square feet at planting time
Dolomitic Lime
- Corrects acidic soils while adding calcium and magnesium
- Apply only when soil pH tests below 6.5
- Use 5 pounds per 100 square feet in fall for spring planting
Prepare the amended soils properly for optimal results. Blend eggshells, then crush into a powder. Add gypsum to a depth of six inches before rain. Combine bone meal with soil from the planting hole. Only add lime after testing the pH. My garden improved tremendously after I began preparing amended soils like this.
Simultaneously utilize amendments with practices that improve soil health. Maintaining relatively consistent moisture levels will facilitate the release of calcium. Adding compost will increase the microbial degradation of the soil amendments. Avoid tilling the soil that has been amended, as tilling can damage the soil structure. I had better results using the gypsum compost tea applications together.
Steer clear of typical mistakes when using natural amendments. Always check pH before applying lime. Never use bone meal on acidic soils. Don't apply eggshells if you have a deficiency. I made these mistakes in my tomato beds.
Test the soil annually to monitor the calcium levels present in your soil. Natural amendments are not a quick fix and require some time to develop, but they sustainably create healthy soil. Your tomatoes will have stronger cell walls and naturally resist blossom end rot over time. Begin amending this year for a better harvest next year.
Read the full article: Calcium Deficiency Tomatoes: Prevention and Solutions
