The soil across the Antelope Valley is fairly consistent and, in most cases, you can grow just about any plant that can climatically grow here.
There are a few areas of the valley that have clay soil, where most of the valley has sandy soils. What we can find is there are areas of the valley that are very high in calcium and most of the valley is high in calcium.
A common visual characteristic of very high calcium soil is the soil is very light to white in color. These high areas the calcium soils will form into a rock called limestone or caliche. In the rest of the Antelope Valley if we dig a hole we might see small white (pea size or smaller) of limestone that has cemented together.
Most of us have enough or too much calcium in the soil for plants to use just as a nutrient. The more calcium in your soil, the higher the pH of your soil can become. Where we have problems with the lack of calcium as a nutrient is in raised beds or pots using artificial potting soil. If you make your own raised beds potting soil with very high levels of organic matter you can have calcium problems.
This has been a long introduction into if the blossom end of your tomatoes rot on the vine, it is a good symptom that your plants are lacking calcium. I have had only heirloom tomatoes growing in containers ever get blossom rot. If I grow heirloom tomatoes in the native soil, I seldom get blossom end rot on the tomatoes. If I grow the more modern varieties of tomatoes in the ground or in containers, the tomatoes do not get blossom end rot.
With all this said, I never add any specialized calcium fertilizer to my landscape or vegetable garden planted in native soil. I will add calcium fertilizer to my container grown vegetables only if needed. Commonly people add eggshells to their soil or compost pile to furnish calcium. I normally do not recommend it, but if you feel you need to, it is best if you grind them up first. Adding eggshells to the compost is more about pH control than plant nutrition.
Garden centers sell fertilizer specifically for tomatoes that contain calcium. I always look for the calcium content in the fertilizer. I have found general purpose fertilizer that contains more calcium and a lower cost than tomato fertilizer. You can also add bone meal which is high in calcium.
Never use fireplace ash, although high in calcium, once the calcium is heated it becomes a product called burnt lime. In ancient times burnt lime was used for concrete and mortar, not good for your soil.
Adding too much of any plant nutrient can cause problems in your soil. If you needed more sodium in your diet and added a bunch of table salt to your soup, you may make your soup inedible because it is too salty. Adding too much calcium to your soil could kill your plants because it raised the soil pH to levels that plants cannot stand.