Influence of soil nutrients on fruit flavor?

Exactly, no one does. And shoot now days everyone seems to think they grow great grapes/wine. What state in the country doesn’t have award winning wines? None is my bet.

It doesn’t take much in the way of soil to grow good fruit trees.

Getting the water right is the real secret to growing great fruit, esp stone fruit.


And you mean less water.

Yes less water at the right time. You think the last 2-3 weeks before harvest. Perhaps because you can seldom hope for more than that. A longer period of water deficit is probably better. And lots of light.

I attempt to carry a water deficit all summer. And what I’ve learned after many years is that in a greenhouse controlling water is even more important than outside. The reason is that in my greenhouse water use is probably half to two thirds as much as outside. It’s a milder environment. So controlling water is even more important than outside here.

People get enamored with rich black soil. I think rich black soil looks and smells great. It just gives a grower a great feeling like all is well in the world. But it’s simply not necessary to grow great fruit. And can be a detriment.

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Organic matter is important for a few reasons, some of which are not mentioned above. Organic matter improves oxygenation of the soil (mentioned above) by letting air infiltrate the soil more easily. Roots need oxygen to metabolize sugars and to produce the acids necessary to absorb nutrients. All else being equal, better oxygen access will go a long way toward healthier and more productive plants. Organic matter also contains humic acid which has a well known effect of blocking certain metals in the soil (aluminum primarily) and buffering the PH. Why is this important? The PH of soil tends to vary by depth with deeper soil often more acidic than surface layers. Addition of organic matter near the surface puts humic acid into the soil which tends to negate the acidity. Note that this is specific to acidic soils, different dynamics affect alkaline soils common in the Western U.S.

Now for my tale of mind blowing good tomatoes. In 2002, I had a few seed of a very rare tomato and wanted to increase the seed. I also had access to a rabbit barn with a couple of truck loads of manure. I shoveled a load of manure and put it on a flower bed in my front yard with full sun and not so good but adequate soil. When done, the manure was nearly 4 inches deep. It started decaying and in a few weeks was a 2 inch thick layer covering the soil. I planted 3 tomato plants into that flower bed. It took 3 weeks before they got started really growing mostly due to cool spring weather. When they finally hit high gear, the vines grew nearly 25 feet long horizontally and each produced between 100 and 300 tomatoes. That alone was amazing but even more amazing was the flavor of the tomatoes. The plants were rampant and luxurious with huge leaf canopies. Every fruit rachis set 3 or 4 tomatoes. I picked tomatoes for nearly 3 months before frost finally killed the plants. I also saved enough seed of that variety to totally saturate the market the next spring. I had about 30,000 seed saved of which I sold most and kept enough to last a few years for my plant sales. I sold the seed for about $20 per 1000 which added up to $400 in seed sales.

This is old but gold. Crops do not use a large quantity of phosphorus, but what they do use is most important and the supply must be good

In the research I’ve seen, in most soils there is no detectable difference in plant growth with the addition of P, this was discovered only shortly before mycorrhizal relationships became studied and known. Apparently fears about insufficient P came from studies using artificial and sterile soil in the research so plants got no help from fungus to gather P.

In the humid region, more organic matter in the soil means more stored, available rain water, generally meaning rich, deep soil stores too much water in a normal year to produce highest brix fruit. My observations suggest that sandy, well drained soils produce the highest quality fruit- WHERE and When RAIN FALLS most of the growing season. I believe this is mostly about there being less stored available water.

Perhaps the year you got highest quality tomatoes with soil dressed with a great deal of partially composted manure was also the result of low rainfall during the ripening and harvest season, or perhaps tomatoes, at least your rare variety, respond differently to deficit and surplus water than most of the species of fruit I grow.

Here is a very interesting article about deficit irrigation. It seems new studies are being done that begin to do a better job of determining the perfect timing and degree of deficit irrigation. Once again, it comes down to the old fruit growers adage- for the best balance of fruit quality and productivity the goal is moderate vigor- the goldilocks sweet spot. The new science suggests the dialing down the growth later in the season provides most benefit to brix levels, which Fruitnut touched on and doesn’t quite agree with. But his goals are different in a green house- outdoors in natural soil, trees need a certain amount of vigor to thrive enough to provide good crops annually.

Rich, dark soils in the humid region encourage vigorous growth- I believe excessively vigorous growth to produce highest quality fruit.

That link is from a company trying to sell something, here is straight research verifying the same thing- but for peaches instead of citrus. Improving Peach Fruit Quality Traits Using Deficit Irrigation Strategies in Southern Tunisia Arid Area - PMC

and for grapes.

and blueberries:

and pears:

Wait, here is research suggesting it also applies to tomatoes: DI is also applied later in the season.

On homestead farms in the old days, the rich bottom soil was often used for grains and vegetables and the thinner upslope soils were used for orchards. What’s best for corn probably isn’t best for apple trees.

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I have zero quibbles with the general statement that too much water is bad for fruit. It holds true for tomatoes and it holds true for watermelons and it holds true for most plants I grow possibly excepting corn.

The year I grew the exceptionally productive tomatoes was also the year I unloaded a couple of cubic yards of rabbit manure at the end of my garden. A volunteer cherry tomato plant came up in the edge of the manure. That plant spread across the top of the manure pile attaching roots wherever it touched. It grew… and grew… and grew until it was 25 feet across and over 6 feet tall. Birds nested in it. I could stand in the middle and could not be seen. It was taking over my garden crawling across the cabbage, overwhelming 2 rows of corn so I decided to get rid of it. I used my tractor and chisel plow to pull it out by the roots leaving a pile of cherry tomatoes 2 inches deep and 25 feet across. My only regret is that I did not have a camera to take pictures.

A couple of the filenames above reside on your hard drive. Nobody else can access them.

Have you seen a tree produce fruit as a result of girdling? My young son decided to whack on a small pecan tree with a knife effectively girdling it about 3 feet above the ground. The tree healed the wound fairly fast but also set a crop of pecans before any of the other pecan trees I had planted. This is worth knowing with some species such as avocado that can be induced to fruit by girdling.

I wonder if you have ever tried overloading a tree with organics? Do you actually know what happens? Serious question, not intended to poke fun or otherwise derail the conversation. I’m willing to bet that a truck load of rabbit manure on an older apple tree that is struggling to live would make a dramatic difference in just one year.

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Girdling will as stated trigger production or if overdone kill the tree. Stress of many kinds causes heavy blooming and fruit set.

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The difference between the citrus and my setup is the citrus ripens all at once. In my GH stone fruit ripens continuously from May until October. I can’t just reduce water in the last 2-3 weeks. And with closely spaced trees and big root systems I can’t zero in on one tree.

In addition for commercial citrus, yield is still paramount. They’re just hoping to meet some modest brix goal for commercial sale. So they still want big yield, not best sweetness. Many people have said the best citrus they’ve tasted is from old trees in southern CA that are abandoned and as a result not irrigated at all during their 8 months of drought. The abandoned tree citrus is probably 10 points higher brix than the commercial stuff in that article.

In the GH when I’ve over stressed trees they appear normal. Maybe drop a few leaves. But the bloom on sweet cherries is totally ruined the next year. The tree blooms but flowers aren’t normal and set is nearly zero. On apricots bloom can also be ruined. The flower buds form but in spring they start to swell, then stall, and fall off. Pluots being part apricot are less affected. Plums, peaches, and nectarines in the same extremely dry conditions bloom nearly normal the next year.

There is literature and lots of it about cherry doubling in the year after heat/drought. Apricots bloom is also well known to be affected by prior year weather. My observations aren’t new. But 99% bloom loss points out how extreme my conditions can be without serious damage to the tree or obvious appearance/leaf loss issues.

Approaching those levels of stress is how you get 26 brix apricots, 32+ brix sweet cherries, and 28 brix nectarines. Not with a few weeks deficit at the end.

And if you want seriously sweet tomatoes you do it the same way. Not by adding lots of manure or having two feet of topsoil with 10% organic matter and rain all summer…

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FN, I don’t believe you know the specifics about DI because you don’t do controlled studies and a lot of what you just posted is opinion based on a very limited realm of experience- that is in TX conditions in a greenhouse where you can’t control which trees get how much water at given stages of development, as you stated. Not that you aren’t extremely knowledgeable compared to most growers on the subject of growing the highest quality fruit.

If you go through the studies I provided, you will see the the goal is usually to get the very highest quality of fruit without damaging overall productivity, not seeking marginally improved fruit.

I strongly believe that there is a point in which ample water helps size fruit without lowering brix when fruit growth is occurring via more cells early in the season and when it hurts, when size is achieved by creating larger cells later in the season. I suspect the same is true on nitrogen’s affect on fruit quality.

The hard part is knowing precisely when this switch occurs, and that is where careful research comes in. You shouldn’t have stopped with citrus, there were several other studies of other species of fruit.

In Tunsia they increased peach brix from 12.3 to 14.3. What they deserve an award?

In the grapes they managed 1-2 points increase.

On blueberry they actually did some good, 3-5 points increase. Most blueberries are 10-13 brix. They got to 18. I’ve gotten to 26.

I’m talking about doubling typical east coast brix. Not a few points better.

We all have limited experience. My results speak for themselves. I’ve consistently grown fruit many others can only dream about.


Dry climates produce very sweet fruit. In my location which has hot summers on a dry year the fruit winds up small but the taste is heavinly.


You are talking about growing fruit indoors, most of the rest of us are talking about outdoors. No one questions your techniques but they apply only to your methods of growing fruit under plastic in low-humidity Texas.

You probably don’t even realize how much better a peach tastes with 14 brix compared to 12- to my palate the difference is huge. I’ve never gotten a peach over about 16- only nectarines have I gotten in the high 20’s. and they were great, but no better to me than those in the low '20’s, which is very high in our region.

Our palates do become used to what we are regularly expose to, as I’ve written on this subject many times.

[quote=“alan, post:75, topic:48706”]
your techniques but they apply only to your methods of growing fruit under plastic in low-humidity Texas.

Come on Alan. Fruit trees are fruit trees. Funny that my experience and results are identical to those reported on this forum by growers in CA. How, by season long water control.

I’m looking for proof that it occurs by season long DI, that doesn’t seem to be established and it defies what I know about fruit development. Consider what I wrote about size and number of cells. I will search longer for a researched answer if you are unwilling to. The researchers seem to assume that it is only later season DI that improves brix levels.

Research is only done for commercial production. Commercially for large scale production you can’t afford much if any loss in yield. So they settle for a small increase in quality.

Clark sees the same thing I see and the same as fruitgrower near Sacramento. For a heavenly increase in quality you have to sacrifice yield on a scale that isn’t commercially acceptable. Except maybe for small growers selling at fruit markets in Santa Monica.

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At exorbitant prices, otherwise, they could not afford it either.


Yes exactly. The other factor is that large scale commercial growers can’t afford to risk tree health. I haven’t seen real damage to my trees from severe water deficits. I’ve also never had a tree in the GH longer than 8-10 yrs. Mostly 5-6 yrs then I’ve moved on to something else or the tree got too big and was taken out.

But there’s no question that tree damage is potentially a real issue. Even a few years off tree life would be commercially unacceptable. Lots of dead and dying fruit and nut trees around here from lack of sufficient water.

Look, CA gets rain many seasons into April with first fruit ripening in May. I don’t see why you keep insisting you know what you can’t know.

This is from the blueberry study. northern highbush blueberry.
Fruit quality and storage. Deficit irrigation had no effect on fruit firmness, soluble
solids, or titratable acidity compared with full
irrigation (Tables 4 and 5). Cutting off
irrigation late, on the other hand, produced
firmer fruit than any other treatment, particularly when the crop was thinned and the fruit
were picked on the last one or two harvest
dates. Enhanced firmness in this case was
likely related to small fruit size (Fig. 1;
Table 3). Fruit firmness is related negatively
to fruit size in many crops, including blueberry (Bryla et al., 2009; Lobos et al., 2016).
The late cutoff also resulted in higher fruit
soluble solids and titratable acidity, which
again was likely due to smaller fruit size
(Dixon et al., 2015). Depriving the plants of
irrigation during late stages of fruit development has been shown to increase desirable
attributes such as soluble solids and acidity
in a number of perennial fruit crops, including wine grape (Mathews and Anderson,
1988), peach (Li et al., 1989), and pear
(Lopez et al., 2011). This is in contrast to
early irrigation cutoff, which in the present
study led to fruit with the lowest soluble
solids on two out of the three harvest dates

Never do i overlook what others know especially about their own soil and situation. Back in 2016 i discussed the same thing i did here with some extra details in this thread.

I tried to go to the link about dolomitic lime but both my servers consider it a security risk. I am always very skeptical of information that comes from suppliers and especially suppliers for home growers because, more often than not, the information is actually mis-information spread to help them sell products. There are even bogus soil testing companies that use the tests to sell you on a bunch of products that have no basis in the science.