How critical is the additional potassium in tomato fertilizer?

[edweather]

I know that fertilizers like Shake and Feed for Tomatoes, Texas Tomato Food, and others, have potassium amounts around 1 1/2 times that of nitrogen. Is this additional potassium critical, or will tomatoes do ok with a basic 3-1-2 ratio. Thanks, Ed

[b54red]

I have experimented with using high K fertilizer with tomatoes and other vegetables and found that fruit development was enhanced with the higher potassium levels. I also noticed that the flavor seemed richer but that could be just the weather which varies every year; but for the past five or six years I have used TTF which has a good level of potassium and have also added wood ashes and my production has increased and the quality of the fruit has been better in both tomatoes and bell peppers. Even with using those higher K fertilizers my soil samples taken before I enrich the beds with organic matter and various forms of fertilizer are always reporting that I need more potassium; so I can only assume that the tomatoes take a lot of potassium out each season since I am adding significant levels of potassium when preparing my beds.

Bill

[biscuitridge]

About how much wood ash do you add?

[MrBig46]

I want to add soluble potassium sulfate to every second dressing this year. I will start at a time when the green fruits are already planted on the plants. I want to make the fruits more tasty and of higher quality during the time of fast ripening (lately in our country very hot and dry summers). Recently, it seems to me that the fruits of some varieties are more acidic for me, although everyone says that the variety is sweet (Jaune flamee, KARMA Pink, etc.). I am too much of a yellow collar for susceptible varieties, which is, among other things, Stupice and the Czech hybrid varieties. During rapid ripening the top part of the fetus takes potassium from the area around the stem and there the potassium is missing and this part will never ripen. I also want to use potassium spray on the leaf.
Vladimír

[zipcode]

Vladimir, just as a note: high potassium will generally make the tomatoes more sour, not sweeter.

Also, Jaune Flammee is quite sour, in fact one of the sourest tomatoes I have tried, it has very sweet walls but the gel inside is aggressively sour.

[b54red]

Originally Posted by biscuitridge

About how much wood ash do you add?

I usually only use the wood ashes as a side dressing at about one small handful sprinkled around each plant. I try to add either muriate of potash or potassium sulfate to get the bulk of my potassium in my soil.

But it obviously wasn't enough according to my soil sample report that just arrived in my email yesterday. I had all 10 beds tested and one bed which I was sure had enough potassium because I tested it two weeks after adding both potassium sulfate and wood ashes to the bed before setting out my onions in it. It showed only half the amount of potassium for a normal reading so obviously I need to up my potassium fertilizing each season. I am sure some of the loss is due to the heavy rains leaching it out this winter.

I am in the process of getting my first tomato bed ready to set plants out in it and my report came back just in time. That bed is way too acidic at 4.9, very low in both nitrogen, and potassium and needs magnesium and some calcium. The organic matter I have been adding has obviously lowered my ph below what I want it to be and I will have to add lime to that bed for the first time in years. I will be using both potassium sulfate and some wood ashes to up my K levels as well as some magnesium and I will get some calcium from the lime I use.

Bill

[bjbebs]

We use wood heat for about 50% of our midwest winter. The burner produces plenty of ash through the season. The gardens see copious amounts spread over the surface. Many years of ash, leaves and horse manure are all my plants need. I don't have the need to test soils. The worms and plant production tells me all is good. Soils tend to balance their composition if just left alone.

[MrBig46]

If I and Labradors 2 write that our Jaune Flamée was sour and more than twenty left it very sweet, I don't suppose any of us will know what is sweet and what is sour. When Labradors 2 writes that KARMA Pink is sour and everyone else is very sweet and I have Karma Pink also sour, that means something. Probably not about the variety, but about cultivation!
Personally, I tested on a Spanish tomato RAF that increasing the electrical conductivity of the EC soil solution increased the sweetness of these fruits (I cultivated separately in containers).
Adding a link to an interesting article.
https://www.researchgate.net/publica...n_esculentum_L
Vladimír

[Nan_PA_6b]

What did you do to increase the electrical conductivity of the soil?

[edweather]

Thanks for the feedback. A lot to think about.

[MrBig46]

Originally Posted by Nan_PA_6b

What did you do to increase the electrical conductivity of the soil?

This is worth reading.
https://www.easy-grow.co.uk/how-to-g...eter-tomatoes/

I had used table salt. So that I wouldn't have salted the soil in the garden, I grew the tomatoes in two containers.
Vladimír

[zipcode]

Originally Posted by Nan_PA_6b

What did you do to increase the electrical conductivity of the soil?

The general way it's done is by increasing (chemical) fertilizer dilution if you have a fertigation system. This way it's not irreversible like with normal salt (even with fertilizer there will be certain things that will not be used by the plants, and EC will increase in time without flushing).
Here is a list with many fertilizers in Europe with what EC you have at certain dilutions: https://www.landwirtschaftskammer.de...te-duenger.pdf
A quick look seems to suggest that high P doesn't contribute much to EC, and N contributes the most. Normally one would use this list to try to minimize EC per nutrition not the other way around.

[RayR]

Originally Posted by Nan_PA_6b

What did you do to increase the electrical conductivity of the soil?

The Electrical Conductivity (EC) of the soil solution depends mainly on the amount of dissolved salts. There are many kinds of salts, natural and man made. Synthetic fertilizers for instance are salt based. Of course too much dissolved salts will damage your plants.

[AKmark]

https://ucanr.edu/sites/nm/files/76647.pdf. I just am not sure about some remarks. Here is a decent write up that may help answer your question. I suggest a 2.2 EC minus water source, and allow a tiny bit to run out the bottom. I use these numbers because we back it up with tissue samples, it is not a guess. I am still using 4-18-38 and follow the directions with great success. Note the very high K. Again, thousands of commercial growers use this, as do farmers market growers.

[MrBig46]

AKmark thank you for the link to the interesting page. The only danger in potassium overdose is that K is an element that can block the uptake of Ca in plants by increasing the risk of BER. Therefore, I want to add potassium only at a time when on the first inflorescence will be relatively large fruit.
Vladimír