I see many references to volcanic soils being very rich but little real information about why, ie soil test results. Some few people have specualted that those soils are rich because of the amount of oganic matter that is in them from the vegetation that was cooked as the lava flowed.

Here is a link that might be useful: Volcanic soils

There are 2 separate parts of your question to consider. The first is 'What is it about these soils that might set them apart from other soils from the nutritional perspective?' The second part is 'What is it about these soils that might set them apart from other soils from the structural perspective?' Your challenge is to determine which deserves your attention. Of course, things like light/day length/temperature and weather patterns all have impact, but you're ability to change those things is minimal, where you have considerable influence over the soil's structure and your nutrient supplementation program.

I grow a LOT of herbs and other perennials in a soil that looks like this:
{{gwi:5648}}

Don't be put off by it's appearance, it's EXTREMELY productive when used with a suitable nutritional program, as a large group of GWers will witness to.

There is another soil that many use for tomatoes with very good results that is made with pine bark fines with a little peat and perlite. Almost all that have used either of these soils are extremely happy with their choice, leaving peat and compost-based soils behind & never looking back.

I'll leave you to your studies and to determining what significant nutritional issues there might be, but if it's soil structure that makes the difference, then it's probably to be found in the drainage/aeration properties of the soil.

Al

As Al has said, there are many other factors that determine flavour other than soil. From my own experience, living in different countries, the character and flavour of the same vegetables are not the same.

A grated daikon from my garden doesn't have the same pungency as one grown in Japan. Interestingly, they also have volcanic soil. My son had a meal in Norway that included brussel sprouts. He cannot stand brussel sprouts but in this case, he ate them and they tasted good. Different soil, different climate, different cook. Who can tell what the factor is?

You can buy volcanic rock, crush it and add it to your raised beds. I would still use soil and compost unless you are very diligent with fertilizer and watering. The advantage of high CEC material such as compost is its buffering or storage capacity for nutrients and water.

I don't think you will get the same flavour in your tomatoes, no matter what you add, as the tomatoes grown in Italy. Just enjoy your fruit and be happy.

Here is a link that might be useful: Soil Development in Volcanic Ash

You could try what I am going to try. I ordered some Azomite rock powder from Fedco Seeds. You sprinkle some on the surface and work it in. It contains trace minerals. I believe it comes from a location in Utah and whether it is volanic, I am not sure. If it performs like the post reply I entered on the Organic Gardening Forum under "Is Rock Dust Safe?", I will be happy.

I think you're mistaken to assume a volcanic soil is "ash based". Mt. Vesuvius ejects a lot of ash when it erupts, but even larger quantities of lava, silica, and pumice. Volcanic soils are rich in potassium, phosphorus, and sulfur, and all kinds of trace minerals, which make them so ferile. They are also extremely well-draining, due to the porous nature of the pumice and relatively large particle size. If you try to replicate this type of soil structure-wise, you will probably have to water and fertilize frequently.

This was a fun question to research, but you're right, I could find no information specifically about trying to re-create volcanic soils or the growing conditions around Mt. Vesuvius. You're probably going to have to experiment. If it were me, I would probably start with a pumice-based growing medium... maybe pumice, granite grit, and a bit of sand? Getting the fertilizer just right will also be a challenge.

--Maureen

I did a Google search for Azomite. It is from an old volcano and seabed deposit.

Here is a link that might be useful: Azomite

Maureen is RIGHT! Coffee plants like low pH soil, high in sulfur. Colombia,Brazil & Hawaii all grow fine coffee on old volcanic soil. Central Texas in USA, is on top of very old volcanic soil.
I say go for it if you find the right mix, then write a book & sale the recipe for the mix. Good Luck
jolj

jolj - I live in central Texas. I don't know whether this area has any volcanic rock or not, but we do have a high pH problem (7 to 8.) I spoke with a liquid fertilizer producer once, and he commented to me that they used ammonium sulfate instead of ammonium nitrate to help lower the pH; it made the phosphorus more available to the crops, thus reducing the the amount of phosphorus that they had to apply overall.

Last year I grew BUSHELS of tomatoes: all hybrids (Better Boy, Super Fantastic and Celebrity) except for a few Romas. This year I'm trying San Marzano, Big Rainbow, Jubilee, Purple Calabash, Brandywine, Great White, Beefsteak and Better Boy. I think I had good success last year because of the sulfur and the native tree mulch I worked into the soil.

Both my spring and fall crops did beautifully, despite the 100 degree days in summer. We have heavy blackland clay soil here, and I've worked a lot of sand into it, along with several piles of compost. I'm waiting until late February before I attempt to plant; we've had some REALLY unusually cold weather here as of late. I hope that changes soon, my tomato plants are outgrowing their pots.

If I can't get the San Marzanos to produce decent tasting fruit, I'll let you know. I'd even crush up volcanic rock out of my flower beds with my chipper and work THAT into the soil if I thought it would help, but I'm going to use a wait-and-see attitude. Please let me know if anyone comes up with any ideas.

tapla has been at this for some time, so I would go with what he said.
cowgril2, thanks for the link.
wanye 5- AMEN!!!
bjustice-search "Ancient Volcanoes", I do not remember if the map show the towns in the fall out or not.

Hhhmmm....reading the analysis for Azomite, it sez that its five highest-percentage contents are:

Silicon dioxide 65.85%;
Alumina (aka aluminum oxide) 11.43%;
Potassium oxide 5.23%;
Calcium oxide (lime) 3.67%;
Sodium oxide 2.07%;

And a jillion trace elemental metals. Can't speak to the value of the trace elements, but the vast majority of the stuff - over 75% by weight - is basically good ol' SAND. : )

Jason

Here is a link that might be useful: Azomite Certificate of Analysis

Well, it's the trace and micro elements that I'm after.....like cobalt, yttrium, strontium, and some others. The silicon is more useful for plant stem strength than you realize.

This year I am going to add some pulverized volcanic rock to the soil where I plant my San Marzano tomatoes. I couldn't find much info on the Italian soil they are grown in either. Every year I do a new experiment with my garden. Sometimes I hit on something good, but not always. I always add a crushed egg shell to the hole where I plant my tomato and I no longer have blossom end rot. That adds calcium. That was one year's experiment.

AMAN again, wayne 5.
Micky, I am not a soil Dr. & I have no ideal if egg shells break down into usable nutrients or not. I compost them, because they do not hurt the soil & the land fill is overflowing.
There is a thread on one of these forums & almost everyone said that we are not getting our calcium from egg shells, & not in one year anyways. Yes I still compost egg shells, tea & coffee bags. Some one said that coffee slows the growth of plants to.I covered the ground with 12 inches of fresh roasted,ground coffee. I did this to kill the weeds & grasses & to compost the waste coffee. The grass grew though the 12 inches & is green & spreading.
So you can not believe everything on the net.
BER is caused by more then one thing, watering & heat play apart in it. I lime & put egg shells in my garden & never had BER here in S.C., in 30 years.

This is my first try at San Marzano tomatoes. I have done research and have read about pumice. You can buy 40 pound bags of pumice at Souther States farm store. It is used in horse stalls to keep them dry. The product is called Dry Stall. It is 17 dollarls a bag. Check it out.

I wanted to know how svirfnebli your tomatoes turned out?

I also am starting San marzanos for pizza napoletana and wanted to hear what the verdict was?

Thanks!

I think you need to collect from volcanic soil from a site. It would have broken down lava in the soil.

This is my second year growing San Marzano tomatoes. I can them for sauce and other canned goods. I have had a bumper crop this year resulting so far in 20 quarts of sauce, 15 pints of sauce, 12 quarts of whole tomatoes, and 15 pints of Rotel. I grow my San Marzanos in garden boxes 6 feet long, 24 inches wide and 11 inches deep. I plant 6 plants per box. I use regular bagged garden soil (the cheapest stuff I can find), bagged compost, composted steer manure, gypsum, and some Peat moss. I fertilize with my own garden cuttings compost, Alaskan fish emulsion, and bone meal. I can't give enough tomatoes away. One helpful hint. If you grow in boxes build a light weight frame around the box about 6' high. You can use it to tie your tomatoes to the top of the cross bars on the frame so they are able to grow tall. It is also very helpful if you happen to live in So. Cal to use shade cloth during the really hot part of the summer to keep them from sun burning and the frame works great for that purpose.

Old thread but here's a thought:

>>Well, it's the trace and micro elements that I'm after.....like cobalt, yttrium, strontium, and some others.

Question is, what are the levels of those elements in your untreated soil? They are going to vary by location depending on the parent rock and the weathering of that rock. These elements are not just present in volcanic rocks. And, depending on how much compost has been added, the concentrations may look nothing like the native soil.

I'm not debating the question of whether trace elements have a huge effect on growth and the taste of tomatoes. I'm simply saying one has no idea whether amendments will improve things without knowing the baseline levels.

Also, there are vastly different types of lava and other volcanic materials, so 'volcanic soil' means any number of things.

IMHO, you can not really replicate it. It is a somewhat acidic soil with an excess of many minerals. Some of these accumulate in the fruit, not because the plant needs them but because it freely uptakes them and then needs to put them somewhere. It is similar to chard accumulating sodium, or certain brassica accumulating selenium. Compost, with its boring, semi-balanced NPK profile, will not have those excessive amounts and will not substitute for it.

As a chemist I would love to see some actual lab analysis data for these Italian tomatoes compared to other ones grown in other places!

Tox, for sure I have tasted salty tomatoes (in Italy among other places). My guess is that the plant will put excess sodium in non-vital organs, and it may even increase the fruit edibility, since in nature sodium is scarce and prized.

When it comes to micronutrients, the difference between an adequate supply and toxic levels is VERY small; and, the excess of which you speak, whether it be an individual or combination of individual nutrients, has the same potential to be limiting as a deficiency of same. My experience has been that what impacts taste most is how much water the fruit has had available after the blossom stage. For example, this has been an extremely dry summer. DW and I canned 3.5 bu of tomatoes last weekend, and predictably, they were the best tasting tomatoes we've put up in over a decade ....... and we can EVERY year.

Being smart is knowing tomatoes are a fruit. Being wise is knowing better than to include them in a fruit salad.

Al

Tapia I understand all that. But my taste buds tell me that those are different from just more sunlight and heat. A plant does not have total control over mineral uptake. If it tries to uptake K, some Na will come up as well. Same for Zn/Cd, and I assume also other chemically similar elements.

""My guess is", "IMHO", "and I assume", "My guess is" that the plant will put excess sodium in non-vital organs, and it may even increase the fruit edibility, since in nature sodium is scarce and prized"".

You're doing a lot of guessing and assuming w/o anything in the way of concrete evidence. Salt (NaCl) might formerly have been scarce and prized in some parts of the old world, but I've never ever, as in not even once, heard of a plant having a deficiency of Na. You're right though, about the rarity of Na in nature, and about how prized it might be if it occurred in its elemental form. Since Na is a highly reactive metal, it doesn't exist in an elemental state in nature. What would make you assume that an overabundance of Na or even NaCl in the soil would make a tomato or any other fruit taste salty? What does sodium taste like. Please don't try to taste it. If you put it in your mouth, much to your chagrin, contact with your saliva will produce a violent exothermic reaction and an explosion of the hydrogen the reaction produces - not to mention the caustic burns it would cause. Na and Cl- are both needed for normal plant growth, but even tiny excesses of either would be highly toxic and produce very notable symptoms.

You'll find that plants grow and taste best when the nutrients they normally assimilate from the soil are A) IN the soil and available for uptake at all times, B) in the soil in a favorable ratio - that is to say in a ratio that mimics the ratio at which the plant actually uses the nutrient, C) at a concentration high enough to ensure no nutritional deficiencies, yet still low enough to ensure the plant's ability to take up water, and the nutrients dissolved in that water won't be impeded (by a high concentration of solubles in the soil solution).

Al

just trying to justify what is an obvious difference in taste. I am glad you can reproduce Vesuvian conditions in the midwest.

I suspect there is a lot more to the equation than trace metals anyway. There are scores of different soil types of course, so even if you re-created the available mineral conditions, the base soil is not likely to be the same. And then there's temperature, humidity, i.e. the climate. It seems like it would be hard to recreate all of this in another place.

OTOH, there are similar climates on different continents. Here in Missouri, there is a stretch along the MO River very much like parts of Germany, so a lot of Germans settled and grew grapes in the silty bottomland soil and made wine similar to what their ancestors made in Germany. So it is perhaps not that difficult.

Yes, there is more. Due to high amounts of compost, my soil is too high in Ca, Mg, P and K (after having started with 7ppm P!). The tomatoes are good but nothing like those from Campi Flegrei. They taste like mid-western tomatoes. I guess I do not use the right kind of compost.

BTW, I vacationed in Campania a month ago for a week, Parco Nazionale Cilento, some 60 miles to the SE of Vesuvio. Got to eat local for a week, home grown tomatoes every day from friends of my hosts, but those too were different. It is specifically the soil, not the climate.

Obviously there is a lot going on with tomato flavours. I happened to read this article:

https://www.growingformarket.com/articles/Improve-tomato-flavor

In short, growing in more dry and even borderline stressed conditions seemed to improve flavour. They also experimented with tomatoes watered with brackish and salty water (even seawater).

I'd guess that the first instance - dry conditions - is a case of a plant prioritizing the fruit for reproduction. Salt may be a combination of uptake of salt or some reaction that the plant sees as stress condition or something else entirely. (These are just speculation)

A thing I didn't know: that tomato plants are technically perennials - although grown as annuals in many climates.

Anyway, climate could be similar but water availability (and things like soil structure/drainage) could still be different, or even just growing and watering practices.

A lot of North American annuals are perennial where there is no frost.

The snake plant/Mother-in-law is a border bed plant in Central America.

Imagine a tomato permaculture garden! Peppers are also tropical and who knows how big they could get in a warm climate.

"A lot of North American annuals are perennial where there is no frost." I understand the point you're making, but what you said isn't accurate. Where a plant grows has no bearing on whether or not it's an annual or perennial. If a plant is CAPABLE, the key word, of surviving for 3 or more growth cycles, it's a perennial. If it dies at the end of a single growth cycle, it's an annual. There are many perennials we grow AS we would annuals, but they are still perennials regardless of where they are grown. Snapdragon, dusty miller, coleus, impatiens ......., all perennials no matter where they grow or if they escape the winter's killing lows.

Al

I'm sure there's a proper name (I now see them called frost-tender perennials on the internet), but for those in colder climates, plants that don't survive winter may be generally known as annuals (or grown as annuals, if you prefer). They may be capable of it somewhere else, but not relevant. I think that's all that was meant.

Get your terminology right people! LOL

Next week, we'll debate BIENNIALS. Tune in for the exciting action.

So svirfnebli what did you end up doing and did you have any success?

Last year I used coffee grounds in my SM beds and it worked pretty. I'm thinking about trying some Azomite and Andesite Mineral Complex to see how that yields. But I would love to hear from others that have had success improving San Marzano's flavor. Thanks!

I suggest that you can burn some wood or get your hands on some wood ash and mix it into your soil! I found that wood ash is the closest to vacanic soil and most of the nutrients are the same! I hope this helps

Carful with wood ash, it raise the pH & that is bad for some plants.

Most plant like 6.0, 6.5, some like 7.0 like asparagus.

So you should have a soil test before adding wood ash or lime.

I live in S.C., which is an ancient seashore & has a low pH of 5.5, 5.0 even 4.5.

I have wild blueberries growing on my farm.

@jolj - I agree that it is completely inappropriate to think wood ash would be like volcanic ash or scoria, or would serve well as a soil amendment unless it's pH and soluble salt content (high in potassium) is taken into account. In fact, the ash and lava flowing from volcanoes varies widely in both physical and chemical properties.

Al

I would add that speaking of volcanic soil makes little sense. It is no coincidence that San Marzano tomatoes are grown in the Nocerino-Sarnese countryside but not on the slopes of Vesuvius itself (I live in Campania).