There are several important reasons to evaluate the soil at your site before selecting what trees to
plant. Nobody wants to go to the effort of planting trees and then watch them die, yet this important step is often missed.
The soil in an area has a big impact on the health of the tree as the soil can either hinder or support root development, provide too little or too much water, and impact several other growth factors.
At a minimum, assess the moisture and clay content of your soil. A clay soil can be rolled into a
tight ball when wet, silt will form a loose ball that crumbles easily, and sandy soil doesn’t hold together at all. Sandy soils will drain quickly, while clay soils will hold the moisture.
Also knowing the history of the site can be an important clue. An area that’s always been forest should have loose soil, while an area that was previously used in some other way may have more compacted soils.
A more sophisticated approach is to also evaluate the pH of the soil. Some trees prefer a more acidic soil, and you can test that to find the acidity levels of your soil. Soils with a pH less than 7 are considered acidic, while those with a pH greater than 7 are considered alkaline. You can test the pH of your soil with a home test kit, a pH meter, or with pH test strips (available online and at garden centers and hardware stores).
Assessing the organic matter is another useful way to evaluate the soil, although somewhat less
precise! Rich soil contains organic matter, which improves soil structure, water retention, and nutrient availability. If the soil is dark brown, crumbly, and has a pleasant scent, the soil likely has a good amount of organic matter and could be considered “rich” for your tree seedlings.
If the soil does not appear to have abundant organic matter, this can be amended with compost, manure or even just leaf litter from the forest. Note: do not fertilize tree seedlings in the first year as they are focused on root development during this time, which can be hindered by fertilization.
This soil info, when compared to our notes about individual tree species, can help you determine
what species will do well on this site. You can also order a soil test via mail through the University of Minnesota if you want a more detailed analysis! The link to the U of M for more information is:
