How can I avoid bottom rot on my tomatoes?

A water-soaked spot at the blossom end of tomato fruits is the classic symptom of blossom-end rot. This relatively common garden problem is not a disease, but rather a physiological disorder caused by a calcium imbalance within the plant. It can occur in pepper, squash, cucumber, and melon fruits as well as tomatoes. You should also be careful in using bleach. While chlorine is a naturally occurring and necessary part of soil, significant amounts of it can cause a condition known as chlorine toxicity. Additionally, undiluted chlorine bleach has a pH of 11, which means it raises the pH of soil significantly.

My father years ago put grass clippings from the lawn around the bottom of the plants like mulch, still works today.

This is caused by lack of Calcium in soil....Bleaching your soil kills beneficial micronutrients needed for healthy soil & plants.chlorine causes degradation to cell membranes, proteins and nucleic acids. What does this mean? Basically, free chlorine breaks apart chemical bonds necessary for normal functioning, which leads to cellular death. tissue death (spotting) can occur depending on the sensitivity of the plant. worse thing you could do in garden especially around something you'll be eating. Why don't the plants get enough calcium to the fruit? This can be due to a number of factors, including:

• Moisture – Too little or too much – We've had dry conditions this summer. Even with mulch, I have lost some tomatoes to blossom end rot. Last week I heard from two different local friends who had problems with rotten, black bottoms on their tomatoes.
• Too much Nitrogen – Dump a load of fresh manure on your tomatoes, and you may be rewarded with lots of green growth and black bottomed fruit. The nitrogen salts may make the calcium in the soil less available to the tomatoes.
• Soil too Cold at Planting – More of an issue for northern gardeners, cold soil can interfere with nutrient uptake to the plant.
• Root damage due to cultivation – Aggressive digging around your plants (for weed control, for instance) may damage the roots. This would also interfere with nutrient uptake.
• Soil pH too high or too low – Either extreme of pH can make it difficult for your tomatoes to thrive
• Susceptible varieties – Certain tomatoes varieties are more prone to blossom end rot than others.

add Gypsum good source for calcium; growers find that the calcium content of gypsum makes it the perfect fertilizer to apply to fields and rows where crops such as tomatoes will grow. Thecalcium added to the soil helps offset diseases like blossom end rot, known to affect certain tomato varieties suffering calcium deficiency. or egg shells ground in blender works too

Thank you so so much!!!! I will purchase some Gypsum before planting this year. Just glad I used very little bleach last year...must be an old wives tale from my aunt RIP...I had lots of tomatoes last year but by late in the season some were getting black on the bottoms! I also will grind up some egg shells before planting! Thank you again!!