In areas where the soil pH is skewed dramatically in one direction or the other and not well suited to the plants you want to grow, you may have better luck growing these items in raised beds or containers. Since the soil for these situations tends to be imported and not influenced by local conditions, it is far easier to adjust and maintain than attempting to do the same for inground plantings. In general, it is difficult to sway indigenous soil pH significantly to any degree and is a temporary adjustment at best.

You can counteract the alkalinity of your well water before using by adding a couple of tablespoons of vinegar to the watering can, but it's tough to make changes if you use drip or other irrigation systems. Be sure to test first to make sure you need to.

As you know our soil pH is in the 8s but there's still a lot of people growing tomatoes. Check out Keith Amelung's website at heirloomtomatoesoftexas.com. He has hundreds of varieties to match anyone's needs. He's 100% organic, too. Keith has sold out for this year, but you can search his site to get names of varieties that you might like. Then look for them at John Dromgoole's or somewhere else up there. Any tomato that will grow for Keith in San Antonio will produce for you in Dripping Springs.

I agree with GardenGal regarding the use of vinegar with irrigation water. There was a woman a couple years ago in Texas with alkaline water and soil and she wanted some help getting things to grow.

I suggested vinegar with the irrigation water and her results were so dramatic she ended up writing an article in her local newspaper sharing the information with townspeople.

Plants don't really care about the soil they grow in. The soil is just there to anchor roots and perhaps hang on to nutrients to be released over time.

What plants care about is the oxygen and water around their roots.

That's why loose soil and good drainage are generally considered important.

pH largely affects what nutrients and in what ratio the soil will make available to the plants. The plants don't take the nutrients from the soil, but from the water around their roots. Change the pH of the water around their roots and you do not have to worry about the pH of the soil.

What is your soils pH? Have you had a soil test done? Are you sure what is happening because the pH is too high and not too low? If soil pH is your problem why is it where its at?
Only a good, reliable soil test will tell you that.

"pH largely affects what nutrients and in what ratio the soil will make available to the plants. The plants don't take the nutrients from the soil, but from the water around their roots. Change the pH of the water around their roots and you do not have to worry about the pH of the soil."

This fundamentally incorrect. The soil is what determines the pH of soil water. When low pH water is added to soil it will quickly change.

To lower the soil pH add 3 lbs of sulfur per 100 square feet. Use 1/3 less if your soil is sandy, and and 1/3 more if it is heavy clay.

Fertilizersalesman,

Using vinegar (or sulphuric acid) with irrigation water is a common practice in growing blueberries and other acid lovers in soils not naturally low enough in pH.

I doubt the commercial growers would bother if it didn't work.

I used an organic sulphur that Peaceful Valley Farm Supply sells.

I guess it was a little too subtle in my previous message, but what I was also saying is that if you are trying to change the soil to match your plants, you are heading for the heartache of poor production, disease, and pests - as you have experienced so far. If you get tomato plants adapted to your soil, and grow them in the proper season, then you have a shot at success. So either change your plants (as I suggested above), or change your soil altogether (as gardengal suggested), but amending the soil to match the misplaced plants you want to grow is a mistake. Talk to Keith at Heirloom Tomatoes of Texas.

Thank you everyone for your good advice. I'll be taking it all into consideration when I pick my plants in a couple weeks.

dchall...this bears repeating: "....if you are trying to change the soil to match your plants, you are heading towards the heartache of poor production, disease, and pests..."

How true!

I would test your ph in your well water. I have a well, it is 7.0-7.2 and I grow amazing tomatoes. First I only grow Better Boy tomatoes. They grow the best in my area, and I also put them on the east side of my house. With the ph of my water, if they are in full sun, I lose them pretty quick. I usually grow about 5 plants and get approx. 50-60 beaf steak size tomatoes a week. In the fall and winter months, of course I put out the usual coffee grounds, bannanas, horse compost, etc. to replenish the soil. Tomatoes deplete the soil pretty quick.

Tab water in Rotterdam is approx. pH 7.6 to 7.8
Since a While I am not able to collect rain water anymore, so I have to lower the water to Ph 5.5 for my Citrus trees in pots (some of them I took all the way from Italy, so I'd rather not take any risks. In the summer I use about 10-15 liters a day for all terrace plants (3-5 gallons?)
I think vinagre is a to risky.
Can I use iron chelate to make the calcium harmless? (or am I way off?)
Any other suggestions besides vinagre?

You have some good suggestions already but I will add 2 more. If you contact your local county extention office and get a soil test, at the time you hand it in you can ask for organic recommendations specific to your area. Also Cottonseed Meal when it breaks down acidifies the soil and sphagnum moss ( peat ) is also low pH.

Elemental sulfur or flours of sulfur are antibiotic when added to the soil. Sulfur is supposed to be a trace mineral and should only be added as some form of sulfate compound.

Hose siphons or injectors can add weak acids into a waterline if desired.

http://www.groworganic.com/item_WMX150_BrassSiphonMixer.html

http://www.groworganic.com/item_WMX345_GrowMoreSiphonMixerInjector.html

Terran

Here is a link that might be useful: siphon mixer

Kolaha, you have no e-mail address so can't be contacted directly, so I will hi-jack this post to suggest 1) you post in the Citrus Forum as they will have more experience than most of us with your trees, and 2) household vinegar is a very weak acid at 3-5%, and is used in cooking all the time, so I do not understand why you don't want to use it, diluted, in the water for your citrus. If you still have questions, why not ask in a separate post of your own? Hope I was some help.

Ccox, I would agree with those who suggest you get a soil test doen, either from you county extension agent's office or from a reputable lab - don't rely on a home test, as they are notoriously unreliable. It isn't only the pH of the soil, but what minerals are present, in what forms and concentrations, that determine how well your plants will grow. Get your water tested also, although there, I think you can get the pH test strips from a drug store anad use them - if they are good enough for medical use then they are probably accurate enough for garden use.

If your soil turns out to be really off, then I think growing in containers will be a lot easier than changing the soil's pH over a large area. If it is only a little off, then using sulfur compounds as suggested, and maybe adding vinegar to your well water, at least in the beginning, as the compounds will take time to react/act with the soil, will make enough difference to make tomatoes happy. Most plants can grow in a pH range, none that I know of demand exactly one pH level.

I wouldn't add peat moss to your soil, as it is very slow to break down, adds little organic matter to the soil, and the latest findings seem to say that it does little to change pH anyway. You say you have been adding things for 3 years to add to the OM, so keep doing that.

Also consider getting a rain barrel to avoid using treated water on your plants. I've been told that the chemicals used to treat water tend to raise its pH. We have one barrel so far and use it exclusively for watering our blueberries.

My best advice is to adapt the plants that you select to your soil and not the other way arround.
Soil is a complex mix of organic matter, air, water, and minerals. The minerals mostly derived from the underlying rocks have the largest effect on the chemistry. The well water has little effect unless your soil has extremely low buffering capacity. Buffering is "how much your soil wants to stay at the pH it is at". If your soil has a lot of buffering capacity, vinegar or sulphur will have little if any effect. If your soil has very little buffering capacity, water may change the pH and vinegar or sulphur would make it swing wildly low.
Tap water is normally a little on the alkaline side, but as I said before rarely effects the overall soil pH. Sulphur, lime, vinegar, etc. can effect soil pH some to fine tune it for better production, but farmers don't use vinegar to grow blueberries in limestone, or lime to grow apples in peat bogs.
Growing plants adapted to your soil and climate will make you a much less stressed gardener than trying to find an organic way to change your climate and soil to match your desired plants. If you choose to modify the soil, get it tested first. The 3 lbs of sulphur is a good "rule of thumb", but only that and the correct amounts added and how often are at best an educated guess even with testing.

Ziggy