I've been working on a gardening app that lets gardeners record information on the plants that they grow in their backyard or field. The gardener can record anything from encountered pests to plant size dimensions and the size of the harvest.

The gardener can also record the dates on which the seeds were sown, the first seedlings germinated, the first flowers appeared or when the first harvest was picked.

Other gardeners can use the data from existing garden journals (that were made by people who live nearby) to generate a very localized planting calendar among other things. Via this planting calendar they'll know exactly which plants grow well in their (micro)climate or on their soil type. They'll also have a good estimate of how long it takes to grow each plant variety that's listed in the generated planting calendar when grown in their own climate.

I would also like the user to be able to filter garden journals based on entered soil properties such as nitrogen content, pH or soil organic carbon. This can be useful because it allows people to easily find out which plant varieties grow well in soil with a high or low nitrogen/clay or coarse fragment content for instance.

Most people don't know what the nitrogen level or acidity of their garden soil is. Fortunately the website https://soilgrids.org/ provides a way to estimate this. These estimations are based on countless soil profiles made in the past and a machine learning algorithm is used to estimate the soil properties of the areas between the different locations where a soil profile was made.

Its a very easy to use map which can give an soil property estimation for any spot on the map by simply clicking on it with the mouse cursor. Also the map settings can be adjusted to make the soil property layers more transparent or to include city and country names.

However there are a few caveats concering the data from soilgrids.org. Firstly the accuracy of the estimations can wildly differ per region. In some regions the uncertainty or inaccuracy of the estimations can be very high. In the FAQ on their website it says that the accuracy of the estimations is between 30% and 70%. Next to this, the map does not show any estimations for urban areas. Wherever there is a large city on the map there will also be a gap in the layer.

So what do you guys think? Do you think the soil data from soilgrids.org is useful enough to include as information in a garden journal? Or is it best not to use this data at all? Personally i think an estimate is still better then no data at all. The soil properties in urban areas could be estimated by averaging a few values of the terrain around the city. but i would love to hear your opinions about this.

2 Answers 2


I did not find that site to be of any use to me. As you mention urban areas have no data. The other issue is that just knowing more about the soil does not allow me to compare. Is 400 dg of carbon per kg good or bad? Most gardening books do not describe what plants need in the terms used on that site.

As well I found it surprisingly hard to find my home on that map. I was only aware that you could show labels by rereading your question.

Anywhere in North America where a basement foundation used poured concrete has a highly disturbed soil profile around it due to topsoil stripping. The underlying soil types are not changed but what get's put back around the foundation is difficult to provide overall guidance on.

So your average urban gardener is not likely to get much from the site. Rural owners who are familiar with soil science may get some benefit.

  • Actually there is one layer mode that does seem to cover cities and thats the soil classes mode.
    – Maurice
    Dec 20, 2021 at 14:27

Depends on your "garden" size. Years ago fertilizer solutions were custom blended for different parts of a field ; think 100 acres. Today, with satellite location on tractors, I believe the most modern agriculture operators use such data. But for something like a 50' X 50' home garden , I think a little extra urea on the corn rows, etc, would handle it.

  • I don't understand your answer @blacksmith37. You seem to talk about fertilizer but the question is about soil data from soilgrids.org. Could you elaborate a bit?
    – Maurice
    Dec 20, 2021 at 6:45

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