No idea. I tend not to trust cheap meters that you can buy. I find that the human finger works well for me, since I check my plants daily and at least twice a day in extreme weather anyway. Some people use a wooden dowel inserted into the soil that they pull up and down, like an oil-checking stick. I would think there would be issues with wicking, but they seem to make it work for them. A gallon of water every day without checking previous moisture levels in a very moisture-retaining mix and in a cooler zone, even in fabric pots, would really be the first red flag for BER. It might be different if you were in sunny, dry, hot climes, although even then, using a mix that is all compost and peat is problematic. Sometimes, plants get better at managing calcium when they get more mature, so your plants may grow out of it.

I know it's too late now, but that may, or may not be the ideal product for correcting calcium deficiencies. It probably should be stated that home nutrient, and pH, test kits are unfortunately not very reliable. Especially for trying to provide the proper conditions to minimize BER, a professional soil test is the way to go. The most cost effective test is usually available through County Ag. Ext. Agents. They don't do the tests, but they usually have information that can direct you to the best source available. If you don't have a local agent (most places in the U.S. have one, but not all,) then a nearby University Ag. Dept., or a local botanical Garden might be able to help. The problem with BER is, as described above, Ca deficiency is actually rarely the problem with in-ground growing. The problem is the plant's inability to make use of the Ca already present. If your soil truly does have a Ca deficiency, and BER is the target, a soil test will give you the ratio of Ca to Mg. This can be important in helping your soil provide available Ca to the plants. Different forms of lime will provide differing levels of Ca and Mg. If though, your soil truly does have a pH of 6.5 (a very desirable pH for vegetable gardens,) and you do have a Ca deficiency, you might want to go easy on lime, or forego adding it altogether. Instead, you might look to pH neutral products like garden gypsum. All that said, we come back to the question of whether there truly is a Ca. deficiency. Ca deficiencies are actually quite rare. More often, as discussed above, it's the plant's inability to take up enough Ca for both, the fast growing plant vegetation, and the earliest developing fruit. There is a limit to how much water and nutrients any plant can absorb through its roots. And, just like humans, plants use the nutrients in some places in their structures before others. In humans, it's blood pH levels. Your body will actually absorb Ca from your bones if your diet is not providing enough Ca to keep blood pH in the necessary range. So, for the growing plant, even with oodles of available Ca in the soil, it may not make it to the earliest developing fruits. Instead of adding Ca, the fix then, is to provide conditions that offer the best opportunity for the plant to absorb as much water and nutrients as possible. In the seedling stage, you want to learn how to develop feeder roots. Early in the growth cycle, after transplanting especially (before flowers are even present,) water deeply, and infrequently. You want the roots to search deeply for water. This will make a very large and efficient root system for the plant to extract water and nutrients (including Ca) from as much soil area as possible. You want to provide an effective mulch to keep the soil evenly moist. Plants are stressed when soils go from very wet to very dry. Deep roots also help to alleviate this problem. I hope I didn't leave anything out, and BER can be very frustrating, but remember, even in ideal situations, some varieties are just more prone to the problem.

Calcium Deficiency can't be solved entirely by using the right soil. Even with the right soil, over the course of a year, the plant will use the calcium to create plant cells and equally important--fruit. To replenish calcium that gets used up in the potted plant, I personally use General Hydroponics CALiMAGic. My understanding is that calcium deficiencies aren't as much of a problem on non-potted plants. But my big question: For potted plants, how much of this stuff are people using?

Can your plant survive it - yes. Can it be prevented - yes. Reversed - possibly if discovered early enough. For most of us it is only an early season issue and easily corrected. This late in the season your odds of getting unaffected fruit are slim unfortunately regardless of what you do simply because there is so little of your growing season remaining. BER begins to develop very early in the fruit's development, while it is still green and growing. So even tho the symptoms are not apparent, much of the damage has already been done. That is why consistent soil moisture levels is so important early on. It's also why container plants, unless grown in exceptionally large containers, are so much more prone to BER. And lastly, some varieties are more prone to it than others. Better luck next year. Dave