BER is almost entirely a water availability issue; the quality of the water is rarely a factor. If the roots can't take up enough water, then the plant can't push the necessary water-soluble nutrients to the ends of the fruit, and it's only the calcium whose absence has that sort of devastating effect. Studies have shown that calcium levels even in the plant stems are normal in BER cases. If your soil is alkaline, the calcium is there and available, so focus on root health... you say that soil moisture isn't a problem, but don't mention how much or how often the plants are watered. Frequent shallow waterings can lead to BER, which not many people realize, as can sudden shifts in daytime temperature even if you have a deep, even watering schedule. Bottom line, shallow or stressed root systems are the problem, as actual calcium deficiency is rare outside of hydroponics and very unlikely in alkaline desert soil. Make sure you're watering deeply every few days and monitor the soil moisture three or four inches down to check that it's evenly moist. --Alison

Growing Tomatoes FAQ: What is blossom-end rot? How can I prevent it? Blossom-end rot is a disorder of tomato, squash, pepper, and all other fruiting vegetables. You notice that a dry sunken decay has developed on the blossom end (opposite the stem) of many fruit, especially the first fruit of the season. This is not a pest, parasite or disease process but is a physiological problem caused by a low level of calcium in the fruit itself. Symptoms BER, or blossom-end rot usually begins as a small "water-soaked looking" area at the blossom end of the fruit while still green. As the lesion develops, it enlarges, becomes sunken and turns tan to dark brown to black and leathery. In severe cases, it may completely cover the lower half of the fruit, becoming flat or concave, often resulting in complete destruction of the infected fruit. Cause Calcium is required in relatively large concentrations for normal cell growth. When a rapidly growing fruit is deprived of calcium, the tissues break down, leaving the characteristic lesion at the blossom end. Blossom-end rot develops when the fruit's demand for calcium exceeds the supply in the soil. This may result from low calcium levels in the soil, drought stress, excessive soil moisture, and/or fluctuations due to rain or overwatering . These conditions reduce the uptake and movement of calcium into the plant, or rapid, vegetative growth due to excessive nitrogen fertilization. Management Adequate preparation of the garden bed prior to planting is the key to preventing BER. Insure adequately draining soil in the bed by adding needed ammendments, maintain the soil pH around 6.5 - a pH out of this range limits the uptake of calcium. Lime (unless the soil is already alkaline), composted manures or bone meal will supply calcium but take time to work so must be applied prior to planting. Excess ammonial types of nitrogen in the soil can reduce calcium uptake as can a depleted level of phosphorus. After planting, avoid deep cultivation that can damage the plant roots, use mulch to help stabilize soil moisture levels and help avoid drought stress, avoid overwatering as plants generally need about one inch of moisture per week from rain or irrigation for proper growth and development. Once the problem develops, quick fixes are difficult. Stabilize the moisture level as much as possible, feeding with manure or compost tea is recommended by many, foliar applications of calcium are of questionable value according to research because of poor absorption and movement to fruit where it is needed but many have reported that foliar application of magnesium (epsom salts) can effect added calcium uptake. Other various suggestions consist of powdered milk, crushed egg shells tea, bone meal tea, Tums tablets, etc. but prevention is the key. Some recommend removing affected fruit from to reduce stress in the plant. BER should not be confused with fruit abortion or inadequate pollination although the symptoms may appear similar. The onset of BER occurs only after the fruit is well on it's way to development while insufficient pollination problems terminate the fruit while still quite small. Here is a link that might be useful: BER FAQ

Holmes, Blossom end rot is a disorder caused by a shortage of calcium to the developing tissue in the walls of the green tomato. Since the blossom end is at the terminus of the fruit, the most severe shortage occurs at that point. Whatever causes the shortage of calcium available to the developing fruit occurs at the roots of the plant where the calcium, and the vast majority of other nutrients required by the plant, is drawn up from the soil. The causes are various but usually are associated extremely dry weather desiccating the soil and locking up the available calcium. But there can be other reasons like sopping wet soil drowning the root system. Another cause could be excessive root pruning like if roto-tilling or too deep chopping with a hoe severs a lot of the fine feeding roots that spread out in search of nutrients. Have you experienced any of these climatic or cultural problems this year? If so, one or more of them may have lead to your BER. Some varieties of tomatoes are more susceptible to BER than other varieties. Roma happens to be one of the susceptible varieties. Most soils have sufficient calcium for tomatoes ... at least that's the case in most all Indiana soils and generally throughout the Midwest. Where do you grow tomatoes? If you suspect your soil may be low in calcium, you should have it tested and add if necessary, but I suspect it may be one of the other environmental factors like drought, chronic wetness ... or just irregular irrigation, where the plant all of a sudden has it's calcium supply interrupted at a critical stage in the development of the green fruit.

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.