It's common knowledge that tomato plants require just the right amount of sun and water to thrive. But there's something else they need that may surprise you: calcium. This vital mineral helps tomato plants form fruit with strong cell walls. Without enough calcium, those walls may collapse, leading to a condition called blossom end rot. Blossom end rot appears as a dark, rotten spot on the bottom of the tomato. It may start out as a dime-size brown patch, then grow bigger and deeper, and eventually become covered with black mold. Blossom end rot can't be cured, but you can help prevent it by making sure your tomato plants get plenty of calcium starting on their very first day in the ground.
Here's what you do:
Feed your tomato plants with continuous release fertilizer with calcium, such as Miracle-Gro® Shake ‘n Feed® Tomato, Fruit & Vegetable Plant Food. Mix some in with the soil at planting time, then feed again every 3 months during the growing season. (Be sure to check the label to find out how much to use and to learn more important information.) No matter where you grow your tomatoes—in the ground, in containers, or in raised beds—this will provide your plants with a steady source of calcium to help keep blossom end rot at bay. Plus, by feeding your plants regularly, you'll be giving them the extra nutrition they need to grow strong and produce a big harvest.
To allow your tomato plants to make the most of all that good calcium, be sure the soil stays consistently moist. Too much or too little water can stress the plants and cause them to be less effective at taking up the calcium they need.
And while it's true that providing a good source of calcium is not a guarantee your tomatoes will never get blossom end rot, it's certainly an effective step in the right direction!