I would say yes the typical gardener who applies 13-13-13 (or stronger) to everything probably overfertilizes yes. When I was selling tomato transplants at a farmer's market, I spoke to more than one person who applied 30-30-30 and were puzzled as to why they got big bushy green plants and no tomatoes.
I only use heavy nitrogen for one crop -- Corn. I apply 45-0-0 when it is knee-high and again when it is 4 feet tall.
For everything else, I prefer a low N number. For tomatoes my go-to used to be TomatoTone 4-7-10 which feels like the perfect numbers for tomatoes to me. Tons of fert for roots, blooms, and fruit, and low N. However they reformulated it to 3-5-6 and it's not nearly as strong (the plants behaved like more like I'd applied 1-3-4). I underfertilized last year and got small tomato plants and not much output (5-10 fruit per plant).
So I'm at a bit of a loss this year as to how hard to hit my tomato plants. I think it's easy to read one research paper based on a specific set of sampling data (which probably doesn't represent the average participant in a garden forum who is likely more circumspect and cautious) and make an overcorrection to our own gardening habits.
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applestar
- Mod
- Posts: 30551
- Joined: Thu May 01, 2008 7:21 pm
- Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)
I do use these kinds of articles as a guide 
Weeds as Indicators of Environmental Conditions
https://archive.lib.msu.edu/tic/tgtre/ar ... 00jun9.pdf
Weeds as Indicators Of Soil Conditions
https://eap.mcgill.ca/publications/EAP67.htm
Weeds as Indicators of Environmental Conditions
https://archive.lib.msu.edu/tic/tgtre/ar ... 00jun9.pdf
The presence of certain weeds isn't accidental.
Good weed management depends on understanding the underlying conditions that allow weeds to flourish. That may mean investigating soil conditions, mowing, moisture or shade conditions first
Weeds as Indicators Of Soil Conditions
https://eap.mcgill.ca/publications/EAP67.htm
(4) Perennial weeds often make better indicators than annuals
Perennial weeds, having been able to tolerate the conditions in a particular locality for more than one year, are often more reliable indicators than annuals, which may survive only one season.
(5) Weed communities are better indicators than single species
The presence of a group of weeds that are associated with one another because of similar requirements for certain soil conditions provides a more reliable indicator in contrast to a single weed species, which may only indicate chance establishment.
https://eap.mcgill.ca/publications/eap67.fig1.gif
https://eap.mcgill.ca/publications/eap67.fig2.gif
I have mostly perennial weeds and I have cut most of the grass out. It is also full of nutsedge and other weeds so, I would not want to use that on the garden. I do use vermicast when I have it. It is about the only organic that has not adversely affected the potting mix.
Feldon, I think you have found the magic number for nitrogen. Vigoro 6-4-6 citrus food is what I use on the tomatoes and they are still 7 ft tall and productive. An organic 3 is like a 1.5% available nitrogen which is what I got the time I tried to go with blood meal and steer manure. I got healthy but short plants. So 4% nitrogen seems to be the magic number. I will have to ask my friend how to convert that to spoons of sulfate of ammonia.
Feldon, I think you have found the magic number for nitrogen. Vigoro 6-4-6 citrus food is what I use on the tomatoes and they are still 7 ft tall and productive. An organic 3 is like a 1.5% available nitrogen which is what I got the time I tried to go with blood meal and steer manure. I got healthy but short plants. So 4% nitrogen seems to be the magic number. I will have to ask my friend how to convert that to spoons of sulfate of ammonia.
Another thing I came to think about when it comes to soil depletion it also has to do with if your adding synthetic fertilizers and no organic matter it will flush out so easy because it lack organic matter to cling on to basically.
Checked the liquid organic fertilizer product I mentioned earlier its N-P-K 3-0-1, thats right has no P apperantly with my organic methods I never cared to much about the N-P-K since its only three out of over hundred elements anyway so to my understanding that far from the whole story, infact its just the teaser from the back of the book. And I'm not about making plants grow I want the best food I can manage to get.
Checked the liquid organic fertilizer product I mentioned earlier its N-P-K 3-0-1, thats right has no P apperantly with my organic methods I never cared to much about the N-P-K since its only three out of over hundred elements anyway so to my understanding that far from the whole story, infact its just the teaser from the back of the book. And I'm not about making plants grow I want the best food I can manage to get.
Nutsedge here can grow anywhere from sand to clay. If it is in a flooded area long enough it will turn yellow but it needs to be drowned for 2 years to kill it. It actually grows anywhere the soil is bare. I have a lot of it in my garden and keeping the garden planted is the only thing that keep it in check since it needs light and my garden has a lot of clay and organic matter and it drains very well.
I have noticed on very poor soils that don't have a lot of organic matter that weeds don't grow well at all and the ground is literally hard as a rock.
I have a lot of organic matter and my soil tests indicate that the soil is only very slowly washing out. It has been 8 years and it is time for another soil test, but I probably still only need to add nitrogen for awhile in most of my plots. Most of that was synthetic fertilizer. Even in the organic herb garden, the soil tests there were also still high P,K, and Ca. Nitrogen is lower there because of the much shorter plants and compost and meal are the usual additives. Meat meal is sold locally and it is made by recycling the old meat and bones from the markets, grinding and boiling it. It is sold as animal feed, but it is used like bone meal and the extra meat adds nitrogen. It needs to be buried and used quickly otherwise it will rot and stink. The mongoose like to dig it up and eat it. I don't really like to use it in the herb garden because they burrow and dig everything up. A similar thing happens with trench composting. The mongoose dig it up for the grubs it attacts.
I have noticed on very poor soils that don't have a lot of organic matter that weeds don't grow well at all and the ground is literally hard as a rock.
I have a lot of organic matter and my soil tests indicate that the soil is only very slowly washing out. It has been 8 years and it is time for another soil test, but I probably still only need to add nitrogen for awhile in most of my plots. Most of that was synthetic fertilizer. Even in the organic herb garden, the soil tests there were also still high P,K, and Ca. Nitrogen is lower there because of the much shorter plants and compost and meal are the usual additives. Meat meal is sold locally and it is made by recycling the old meat and bones from the markets, grinding and boiling it. It is sold as animal feed, but it is used like bone meal and the extra meat adds nitrogen. It needs to be buried and used quickly otherwise it will rot and stink. The mongoose like to dig it up and eat it. I don't really like to use it in the herb garden because they burrow and dig everything up. A similar thing happens with trench composting. The mongoose dig it up for the grubs it attacts.
Then you shouldnt worry to much of soil depletion in my opinion. Is it washing out? Or is your produce taking it out? Can the test really tell wich?
Came to think about another thing (my mind works slow). Nitrogen fixing plants most people heard of, they work with bacteria, but there is also bacteria that without direct relationship with any plants also binds nitrogen from the air, these bacteria are very sensetive against the modern synthetic growing methods thus increasing the need for external nitrogen.
I'm no fan of using animal based products, many likes it becouse it keeps the herbivorous animals away and they have been nothing but beneficial to me.
Came to think about another thing (my mind works slow). Nitrogen fixing plants most people heard of, they work with bacteria, but there is also bacteria that without direct relationship with any plants also binds nitrogen from the air, these bacteria are very sensetive against the modern synthetic growing methods thus increasing the need for external nitrogen.
I'm no fan of using animal based products, many likes it becouse it keeps the herbivorous animals away and they have been nothing but beneficial to me.
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Taiji
- Greener Thumb
- Posts: 921
- Joined: Fri Oct 05, 2012 3:19 am
- Location: Gardening in western U.P. of MI. 46+ N. lat. elev 1540. zone 3; state bird: mosquito
Imafan, I would like to try that Vigoro 6-4-6 on my tomatoes this year if I can find it. I have seen some bags of citrus food in the stores here, but never noticed the proportions. Wondered how often to apply in the season, (my season is about 6 months, give or take), when to apply, etc.
I usually get really huge tomato plants with lots of growth and I do usually get a good harvest eventually, but suspect I could do better. I think I use maybe too much N. I just use a multi purpose fertilizer, supposed to be good for this area. 16-8-8. Probably too strong?
I usually get really huge tomato plants with lots of growth and I do usually get a good harvest eventually, but suspect I could do better. I think I use maybe too much N. I just use a multi purpose fertilizer, supposed to be good for this area. 16-8-8. Probably too strong?
Taiji:
That much nitrogen would only benefit in the growing stage, once you want flower and fruit preferably before that should change to a product with lower nitrogen. If your using a slowrelease product that one aint that suitable for tomatoes. Better for leafy green vegtebles and such. Excess nitrogen will grow foilage not fruits. It will work but with lower yealds generally.
You may use a slowrelease product with lower nitrogen and then add something like nettle tea in the early stages to promote growth.
That much nitrogen would only benefit in the growing stage, once you want flower and fruit preferably before that should change to a product with lower nitrogen. If your using a slowrelease product that one aint that suitable for tomatoes. Better for leafy green vegtebles and such. Excess nitrogen will grow foilage not fruits. It will work but with lower yealds generally.
You may use a slowrelease product with lower nitrogen and then add something like nettle tea in the early stages to promote growth.
6% nitrogen is pretty low for a synthetic and it is a slow nitrogen so it does not affect fruiting as much as say urea would. And plants do need more nitrogen while they are in their growth stage. If the plants don't grow they don't have the mass to support a lot of fruit. Nitrogen does not hang around for long because it is easily lost. The trick is to have it when the plants need it and to get the dosage and timing right to support the plant in the growth stages but to reduce the available nitrogen to promote more fruit later on. The Michigan University fertilizer study determined that is was not high phosphorus at all that promoted more fruiting directly but the relative lack of nitrogen. In other words too much nitrogen kept the plants in growth mode at the expense of fruiting. Reducing the nitrogen at the right time for each plant was what stopped growth and moved the plants into their bloom phase. The highest NPK I found organically was blood meal at 13%. Nitrogen and it was the most rapid in release, but it is very expensive to use. Other organic sources of nitrogen only have a fraction of the N available dependent on a lot of factors: microbes present to mineralize the organic nitrogen, soil temperature, pH, moisture, and rate of volatization and demineralization. It makes the release of any organic nitrogen unpredictable while synthetic nitrogen is readily available to plants and uptake is more predictable.
Young plants need more nitrogen than older plants. if they don't get it when they need it ultimately yields are lower. It is also why it can take years for an organic field to increase yields because it can take years for some forms of organic nitrogen to release. It is also why nitrogen is the most limiting factor of growth on organic farms.
It is also why it is a good idea to use just enough to get the growth that is desired without too much extra that will inhibit blooming or fruiting or cause too much N excess in the environment.
It is why I divide the nitrogen into installments. The first when the seedlings are transplanted or as a starter fertilizer (sulfate of ammonia) , next with the first bloom (citrus food in potted plants only) , then with the first fruit and monthly thereafter. It is also why I use a low N fertilizer for the subsequent feeding in pots. In the ground they get only starter sulfate of ammonia and I have been reducing the amounts, but it looks like I can cut a bit more in the acidic plot but increase it in the alkaline plots since growth is still under what is expected especially for tomatoes in the alkaline plots.
https://www.ipni.net/ppiweb/bcrops.nsf/ ... 8-4p16.pdf
Young plants need more nitrogen than older plants. if they don't get it when they need it ultimately yields are lower. It is also why it can take years for an organic field to increase yields because it can take years for some forms of organic nitrogen to release. It is also why nitrogen is the most limiting factor of growth on organic farms.
It is also why it is a good idea to use just enough to get the growth that is desired without too much extra that will inhibit blooming or fruiting or cause too much N excess in the environment.
It is why I divide the nitrogen into installments. The first when the seedlings are transplanted or as a starter fertilizer (sulfate of ammonia) , next with the first bloom (citrus food in potted plants only) , then with the first fruit and monthly thereafter. It is also why I use a low N fertilizer for the subsequent feeding in pots. In the ground they get only starter sulfate of ammonia and I have been reducing the amounts, but it looks like I can cut a bit more in the acidic plot but increase it in the alkaline plots since growth is still under what is expected especially for tomatoes in the alkaline plots.
https://www.ipni.net/ppiweb/bcrops.nsf/ ... 8-4p16.pdf
My garden is acidic so nitrogen is most available. The other nutrients are high as well and I don't have to add any thing else. Since my green plants are still giants, I know I have enough and don't need to add more. If I add more none of the bulbing crops like daikon, beets, or garlic produce any appreciable roots, only very large tops.
In more alkaline conditions like the herb garden pH 7.8 and the community garden pH 7.4 root crops do better, partly because nitrogen is less available and with my type of soil phosphorus becomes more available at the higher pH. All the plots have added organic matter. Even though the alkaline plots get more nitrogen than the acidic plot, the roots crops grow better in more alkaline conditions and tomatoes are bigger and more productive in acid conditions. I am still adding too much nitrogen to my acidic plots even though I only use a starter. Most people would provide nitrogen in installments, I just have a lot of nitrogen so I don't need to. In fact, after I plant a high nitrogen feeder like corn, I have enough residual nitrogen for the scavenger crop of Asian greens that follow.
I do not grow a lot of legumes in the acidic garden since I grow those in the tomato pots, so I don't really know how much nitrogen fixing goes on. I don't like a lot of legumes so I don't really plant much. At the herb garden, I have inoculated cow peas as a green manure and the nitrogen fixing nodules increased from 0-4 to about 12, but it did not last even with double cropping in alkaline and poorly drained soil.
If your soil is alkaline, and you are not getting giant leaves on your plants, it is probably better to give nitrogen in organic or inorganic form and time the release so that it is most available to the plants when they are in a growth spurt. It is harder to do organically since the release rate is less predictable. Nitrogen releases slower in cold soils since the microbes are less active and Nitrogen is volatile so it should be worked into the soil not just applied on top.
You need to apply any fertilizer dependent on your soil conditions and plant needs. Heavy feeders like corn, broccoli, and cucumbers want more nitrogen than heavy givers like beans, peas, and peanuts (legumes). Light feeders like the root crops beets, and onions need less. Low nitrogen users are turnips and sweetpotatoes.
I rotate my heavy feeders with scavenger crops that will get no additional nigtrogen.
In more alkaline conditions like the herb garden pH 7.8 and the community garden pH 7.4 root crops do better, partly because nitrogen is less available and with my type of soil phosphorus becomes more available at the higher pH. All the plots have added organic matter. Even though the alkaline plots get more nitrogen than the acidic plot, the roots crops grow better in more alkaline conditions and tomatoes are bigger and more productive in acid conditions. I am still adding too much nitrogen to my acidic plots even though I only use a starter. Most people would provide nitrogen in installments, I just have a lot of nitrogen so I don't need to. In fact, after I plant a high nitrogen feeder like corn, I have enough residual nitrogen for the scavenger crop of Asian greens that follow.
I do not grow a lot of legumes in the acidic garden since I grow those in the tomato pots, so I don't really know how much nitrogen fixing goes on. I don't like a lot of legumes so I don't really plant much. At the herb garden, I have inoculated cow peas as a green manure and the nitrogen fixing nodules increased from 0-4 to about 12, but it did not last even with double cropping in alkaline and poorly drained soil.
If your soil is alkaline, and you are not getting giant leaves on your plants, it is probably better to give nitrogen in organic or inorganic form and time the release so that it is most available to the plants when they are in a growth spurt. It is harder to do organically since the release rate is less predictable. Nitrogen releases slower in cold soils since the microbes are less active and Nitrogen is volatile so it should be worked into the soil not just applied on top.
You need to apply any fertilizer dependent on your soil conditions and plant needs. Heavy feeders like corn, broccoli, and cucumbers want more nitrogen than heavy givers like beans, peas, and peanuts (legumes). Light feeders like the root crops beets, and onions need less. Low nitrogen users are turnips and sweetpotatoes.
I rotate my heavy feeders with scavenger crops that will get no additional nigtrogen.
If you have alkaline soil chicken manure is not good for that. Layer chickens are fed calcium and what goes in comes out. Chicken manure can raise the pH another 0.5 point higher which is fine if you have an acidic soil but will make a pH 7.8 rise to pH 8.2. The local composter stopped adding chicken manure to their compost garden mix because of that. The compost tested at a pH of 7.8.