Well, water is not the issue, it's a nutrient deficiency. However you are still probably overwatering in my opinion.

You can not solve the problem by adding only the missing nutrient because it requires the proper ratio of other nutrients in order to utilize the missing nutrient. In the future, make sure you get a soil test and incorporate lots of compost into your soil so you know it is nutrient rich, then look for varieties resistant to BER in the first place.

So long as you have good drainage, the plants will take what water they need. General rule of thumb is that gardens require one inch of water per week by supplementing rainfall.

You will have to adjust throughout the season and be attentive to the amount of rainfall you receive each week. There are two schools of thought on watering. Frequent shallow waterings or less frequent long, deep waterings. The general rule of thumb is that mature plants need 1-2 inches of rain per week in summer. You should provide whatever portion of this moisture is lacking. One inch of rain equals 65 gallons per 100 square feet of garden space. But this is just a guide. Time of the season, stage of the plants, soil composition, and many other factors affect the amount of water required. Be consistent during fruit production.

Mulched plants require less water than plants that are not mulched. Raised beds require more than non-raised beds.

If a good amount of compost is incorporated into the soil, less water is needed. Compost holds 6 times it's weight in water.

Watering too frequently and too heavily is just as hard on plants as too little water. Roots require oxygen just as much as they require water and nutrients.

Dry winds dehydrate plants.

Cooler temps require less water.

Those using drip irrigation whether from a soaker hose or milk jug are likely getting the best use of their water which is going right where it needs to go and the ground has time to absorb it.

There are hundreds of methods of watering. Whatever you do, just be consistent. But I do agree, twice a day sounds like too much. Roots require oxygen equally as much as they require nutrients and water.

I personally believe in a couple of deep waterings per week with the use of 2 inches of mulch to reduce evaporation and maintain a more stable soil temperature.

Plants recover from dehydration much better then they ever recover from the roots being suffocated by drowning so under watering is better than over watering until you get the hang of it. Oxygen is equally as important as water and nutrients and rain water is always better than municipal tap water.

I am watering every two days, not twice per day. I ammended the soil with a balanced feritlizer at planting time.

-Joe

Hi Joe: you & me are same zone & area. All my plants are in raised beds or whiskey barrels except for a couple of volunteers. All my plants get good sun.
I water once every 5 days, more or less. I would guess 1 or 2 gallons each watering/per plant. Our weather has been cooler than usual in my opinion...if it were hotter I would water a little more.
I have a layer of mulch around each plant too.
I'm not an expert on BER or its causes so I can't help you there. But as to watering, less is better as long as the plants are growing well, blossoming & setting fruit.

If you're watering too much depends on the size of the emitters, the size of the garden, etc...

Take the size of your garden in square feet and multiply by 0.09. That is how much water you need per day in gallons. For example, my garden is 40 x 80. I need 288 gallons per day.

Now take the size of your emitters and multiply by the GPH rating. My plan is 333 .5 GPH emitters, 53 1 GPH emitters, and 33 1.5 GPH emitters. 333*.5+52*1+33*1.5= 269

Divide the gallons needed per day by the result of the emitters and multiply by 60 for the number of minutes a day watering needed. 288/269*60=64 minutes

It should be a lot less if you mulch well and concentrate the water on the plants with drip.
Hope this helps.
Rick

The amount of water is not by any means definitive for every gardener, an inch of week is the "average mean". It depends on the quality of the soil, the water retention abilities of the contents of the soil, and whether mulch is used. If you really want to know if you're watering enough, wait three to four days after your last watering. Then dig down to the bottom of your bed. See if it is still moist at all. If it is, you do not need to water. Remember, your plant's roots need to breathe equally as much as they need to drink.

To try and address your original question there are several products for blossum end root. The one that I use and appears to work well is Calcium Chloride based. I drench the leafs of the tomato plants several times during the growing season. It also helps my summer squash

I was told before I started the garden that Calcium was lacking in our soils.

Al

I have also had BER problems when growing tomatoes in pots. Using one calcium antacid tablet per pot stopped it; I then soaked the soil with water to which lemon juice had been added, to balance the pH. The results were not long-lasting; but it did allow me to get enough tomatoes to save seed, which was my primary intent. Perhaps calcium citrate alone would be just as effective.

It should be noted that the same two varieties which had BER in pots, had little to none when planted in open ground. Perhaps the higher soil temperature of the pots is a factor, and/or the lower moisture level caused by rapid drainage.

It may be best to consider a more long term amendment when calcium is deficient. Here is an excellent article with very specific advice.

Here is a link that might be useful: Calcium is the King of Crop Nutrients

While written for hydroponic growers, here is how tomatoes in particular utilize calcium and why there are sometimes problems with its transport to fruit and leaves no matter how you grow crops:

Calcium - A Transportation Problem

Thank you, Anney, that was an interesting link. It has as least partially confirmed my suspicions regarding the effect of temperature. I am growing another tomato in pots this year, and will try using shade to reduce BER.

zeedman

I've also read that unstable temperature fluctuations can result in BER, in fact, almost anything that stresses a plant can mess up the calcium distribution.

Did you notice this quote?

"The incidence of BER in a crop, can be reduced by spraying with a 0.2% calcium nitrate solution - however it is the green fruit which must be sprayed as spraying the leaves alone has no beneficial effect."

I really wonder if this is true. I didn't think tomato skins are porous enough to absorb anything applied to their surface and the fruits relied entirely on nutrients brought to them through the plant tissues.