Sawbones
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Disaster

Newbie here. First a little history of my dilemma. 3 years ago I had a thriving heirloom tomato crop. 2 years ago a friend dumped mushroom compost that was mixed wrong at the mushroom farm. Killed all my tomato plants; nothing would grow in that plot including weeds. Soil testing results revealed ALL nutrients were off-the-chart excess quantities so NOTHING would grow in the garden not even weeds. Garden abandoned for 2 years. 3 weeks ago I had the top 6 inches soil scraped off and replaced w/ sandy loam from out in the pasture; tilled the loam w/the soil underneath. I planted 14 heirloom tomatoes just 4 days ago. (in preparation to planting I laid the plants on their side in the dirt) Today, 4 days later, I've got early blight on all plants. Seems the new dirt is contaminated w/ fungi.
Question: Is there a way to rid the garden of the killer fungi? How to sterilize the soil?

Thanks in advance

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applestar
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Could you give us the actual numbers in the soil test results? Honestly I wouldn’t be able to interprets them but there are members here who are fluent and knowledgeable.

My personal instinctive and intuitive proposal would be to take this year off solanacea and try to grow other, hungry crops like corn and/or winter squash to try to deplete some of the excess…. since I don’t know what “too much that nothing would grow” means (… I’m curious if you also tested for herbicides and other chemicals)

Maybe interplant with other crops that are known to help with soil biology like marigolds, garlic, and onions during the warm months and then mustards and radish at the end of the summer through fall (and winter if you live in milder winter area).

…alternatively, another idea I would explore would be to put duu in on a heavy layer of freshly chipped wood and inoculate with appropriate strain of mushrooms for the location ( wood chip substrate, sunny area, etc. )

Sawbones
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Misplaced the soil testing data but I assure you ALL parameters tested in the "Excess" range or beyond. pH was 7.0. The dirt was toxic.

"nothing would grow including weeds", meaning just that. Anything planted in there died and NO invading weeds appeared. It was a moonscape. Even the dewberry vines I tried to kill-off for years died. Plenty of weeds in spots where no compost was spread.

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applestar
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Wow…. SO I’m displaying more confusion, but what could have been added that would result in such excess? Spreading evenly, “tilling” or digging and mixing to *dilute* with existing soil and/or added low/no fertility but plenty of organic matter doesn’t help to lower those numbers overall?

I tend to think “organic” and “biodynamic”, so I would be looking into phyto- and myco-remediation. So if for example, you were specifically dealing with too much nutients, it seems like adding fresh wood chips and growing mushrooms would do wonders. Of course simply mixing the wood chips into the soil — something you are taught NOT to do — would lock up the nitrogen as well as lower the pH somewhat. It still wouldn’t allow you to grow anything, but it would begin to remediate the soil.

Similarly, if anything would grow at all, the trick I think would be to use them for remediation by letting them grow almost to maturity — using and taking up the nutrients as they grow — and then reaping the entire plant material and discarding them off-site. By identifying what kind of plant(s) they were, you might be able to tell what they used up most. …Or keep testing the soil.

If growing in the soil is indeed impossible this year — and I think maybe until the ground is back to safe levels — you may have to use containers and above-ground/no-soil-contact planters (like they recommend for urban gardening where lead, etc. contaminated soil is present). You could build them yourself, or use things like stock watering tanks, or maybe sub-irrigated planters like Eartboxes and Earthtainers, Global Buckets

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applestar
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Out of curiosity, I searched for what could have been wrong with the mushroom compost — (just a cut and paste of immediate hit)
Why do you have to be careful when using mushroom compost?
Mushroom compost should be used with caution due to its high soluble salt levels and alkalinity. These salt levels can kill germinating seeds, harm young seedlings, and cause damage to salt-sensitive plants, like azaleas and rhododendrons.
https://www.coastallandscape.com.au › ...
A Word of Warning About Mushroom Compost

imafan26
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The mushroom compost is alkaline and most compos-ts start off acidic but b--y the time they are finished, they end up being alkaline somewhere between pH 7-8
It is not just mushroom composts, most composts are like that unless they add a high nitrogen source to the compost like oak leaves, pine needles, or urea.

I am with Applestar on the recommendation. Fungi can stay in soil for a very long time. It really depends on the kind of fungi it is. If the compost was not finished, the fungi are still decomposing the organic matter so you have to wait on it.


You can solarize the soil for 6 weeks in the hottest part of summer to try to kill some of the spores. Again, it really depends on what kind of fungi. I used sta green potting soil in my tomato pots and I hat mushroom sprouting in the pots, Those fungi are annoying, but they did not harm the plants. The other option to sterilize the soil would be to cook the soil in the oven which I would not recommend, it stinks, or in a soil steam sterilizer, but it will kill all the good organisms in the soil as well. Another way would be to steam sterilize or use hot water.

You got pasture soil. Are there any animals in the pasture. You should not use that kind of soil in an edible garden until it has been composted for at least 90-120 days. If your nutrients epecially phosphorus and calcium were already high, you want to avoid composts and manures.

if you are going to do an organic garden, it is best to put in your compost, manures and organic fertilizer 2-6 months in advance, except the nitrogen. You should only add what your soil test recommends. If the levels are already high, more is worse. You will need to be selective and add only what is needed. You only want a total carbon between 2-5% or you may have problems. So, you don't want to plant in a couple of feet of compost. If the numbers were already off the chart, you would not want to add any organic matter from a pasture because that would just maintain very high levels of phosphorus.

Test the soil for pathogens that you don't want in the soil, nematodes, pithium and phythophthora. If the soil test was done three years ago, it is time to do another. As long as those are not your pathogens, you can take it out, pile it up, and slowly add the pile to your compost pile to use it up. It depends on how hot the compost gets and how often you turn it. If it has really bad stuff in it, get rid of it. Phythophthora can live in the soil for upwards of 20 years.

You said the soil test numbers were all high. It probably still is. But plants can grow even with high numbers depending on how high it is and the amounts relative to other elements in the soil Lab normals are usually low 6.0-6.2 , but unless you are growing plants that require either extreme acidic or extreme alkaline conditions, most plants have a greater pH tolerance and for most plant a pH 6.0-7.2 is good enough. Once you get above pH 7.5 tomatoes will still grow, but might have more problems with micro nutrient deficiencies. Phosphorus can get very high to the point of becoming a pollutant, but plants will tolerate phosphorus levels of 2000 easily. Just don't add any more, which usually means if your organic matter is already 2-6%, don't add any compost or manure. Depending on your soil series, most soils will tolerate a higher than normal calcium. Where you run into problems are with availability of minerals and micro nutrient when pH levels are extreme or some elements like potassium and phosphorus can inhibit the absorption of micro nutrients if there isn't a good balance.

When you do the soil test ask for pH, major nutrients, organic carbon, and tests for pathogens.

Since your tomatoes got blight, the blight is in the soil and spores are probably in the air as well. If you are sure it is blight, then you may have to select for blight resistant plants. Until you get a current soil test and find out the status of the soil, I would not plant anything except test plantings of things like radishes and beans. If they don't germinate or run into trouble then you know the soil needs more help. If they do grow, the soil test will tell you what to add to the soil or how to dilute it. Dilution is usually with more soil, but basically, you have to find a source of good topsoil that does not have organic matter in it.

You said nothing would grow there. If it has been bare then grow a interrim crop to test if the soil can support life. If the numbers are too high to support life, you can dilute the soil and try to plant a scavenger crop of a grain like oats, buckwheat, wheat, rye, or brassicas. They don't need nutrients, except nitrogen, if your soil is already nutrient rich. They will scavenge the nutrients. Normally, they would be tilled in to basically sequester the nutrients, but you are trying to get the excess out of the soil, so harvest the plants and don't put any of it back because you want a negative balance. This is a slow process, You would have to plant and see if there are improvements and do regular soil tests every 2-3 years and carefully manage your inputs.

https://www.ncagr.gov/SWC/costshareprograms/ACSP/documents/nutrient_scavenger_crop.pdf

If you want to grow a few heirloom tomatoes, I suggest you grow them in 20 inch pots minimum 15-25 gallon pots in potting soil. Potting soil is sterile so it does not have any pathogens in a new mix. I take the potting soil bag and cut it to fit inside the pot and make a slit for the stem of the tomato. I put the white side up to reflect light and heat. It isn't pretty, but it does keep the soil from splashing on the tomato leaves. Take off the lowest leaves if the plant does not need them. Preferable set up the pots for drip irrigation, otherwise water carefully to prevent splash back on the leaves. Since they are not blight resistant you probably will have to be on a preventive fungicide program.
https://extension.umn.edu/disease-manag ... and-potato
https://extension.umn.edu/disease-manag ... ate-blight
https://ipm.ucanr.edu/agriculture/flori ... pathogens/



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