What Does Your Soil Need?

Apr 29, 2021

Kailey Foster: When you're new to gardening, it's easy to just hop right in and start planning, but there is a step you may need to consider before you jump right in. Joining me today is Sheriden Hansen, USU Extension Horticulturist in Davis County to talk about soil testing.

First, what can a soil test tell you?

Sheriden Hansen: So, a basic soil test will tell you a couple of very key things about your soil. It will tell you what your PH is. So, how acidic or how alkaline your soil is. This can affect how nutrients are absorbed by your plants. 

It can also tell your basic macronutrient nutrients in the soil,  such as phosphorus and potassium. We don't typically test for nitrogen because that washes out of the soil quickly. However, phosphorus and potassium build up quickly and can cause some problems. 

It should tell you your salinity or salt concentration in the soil as well,

KF: How can a soil test help your garden?

SH: Knowing what your macronutrients are, that phosphorus, that potassium is already at in your soil before you start planting. It can help you know whether to add to or amend to your soil correctly so that we don't cause a bigger problem. For instance, if you have a lot of phosphorus in your soil already, we don't want to add a fertilizer with phosphorus in it and cause a problem.

KF: So, how do you test your soil?

SH: It's simple to do. We have a lab at the USU campus, and you can go to the USU Analytical Lab website. It will take you through the steps very simply. You need two cups of soil. 

You're going to select that soil from the site that you're interested in. So, if it's a vegetable garden, you're going to select soil from a couple of different locations in the vegetable garden, mix it all in a bucket. Then you're going to take out two cups of the garden sample, put it in a bag, print out the form from the analytical lab, and send it right into the lab. 

KF: How often should you do this?

SH: I recommend that people get their soil tested about once every one to two years. It helps you kind of gain an understanding of what's going on in your soil in your garden. Then from year to year, you can see what the plants use up. As you add things like leaf mulch or organic matter, or anything like that to your soil, you can see how that changes your soil structure.