Organic Gardening - Soil Testing

It's that time of year - the snow has almost entirely melted; the ground is thawing; tulips, daffodils, and hyacinths are peeking out of the ground; and the air is warming up. Spring is finally showing us that it's here... or at least not far off! It's also the time of year to be thinking about your vegetable and/or fruit garden.  Hopefully you've already ordered your seeds and have sketched out your garden plans.  You also need to be thinking about the nutrient needs of the fruits and veggies you are going to grow.  A lot can be learned from a simple soil test. 

This is the perfect time to get your soil tested for your vegetable gardens. It generally takes about 3-4 weeks to get your results. So you'll want to get your soil samples in very soon in order to have time to address any soil deficiencies or adjust pH prior to planting.  Of course you can also amend the soil after planting, as well. I briefly mentioned the importance of soil testing in a past post on gardening basics, but I thought I'd provide a little more information on the topic.  

Why have a soil test?
The basis for nutrient-dense, healthy vegetables and fruits is a good, fertile, nutrient-dense soil. If you're lacking nutrients and minerals in your soil, you're lacking them in your food. Contrary to what many people believe, vegetables and fruits are not created equal. You need to have your soil tested so that you are aware of any problems or deficiencies in your soil.

What is a soil test?
A soil test will tell you what your pH is, as well as the levels for nitrogen, phosphorus, calcium, lime, and magnesium. You can also pay extra for mineral testing, which I would recommend. Your test results should also provide recommendations for addressing any deficiencies. Test results can be difficult to interpret.  MSU has some great information explaining how to interpret your results. 

How often do I need to test my soil?
It is recommended to have your soil tested at least every 3 years. However, if you test your soil now and find out you are lacking many nutrients and minerals, I'd suggest having a test done in the fall or again next spring to see if you were successful in amending the soil.

Who does the testing?
Your university extension office is probably your best bet. For Michigan, contact the MSUE office for your county. For Genesee County, you need to pick up a soil test box from the MSUE office, take your samples, and mail it in to the MSU Crop & Soil Sciences Testing Lab. You can see the fee schedule here.

How do I take a soil sample?
There should be instructions included in your test box, but here are the instructions that I was provided by MSUE - its really a very simple process:

1. Decide whether you want to test soil for the lawn, trees and shrubs, flower garden, or vegetable. If growing more than one item (vegetable and flower) together, use the plant code of what you are planting the most of. Soil sample information form will be included with soil box. Use a spade or trowel and a clean plastic pail to obtain the sample.

2. Collect 10-15 representative soil samples from one type of landscape area – such as your lawn, flower garden, around trees or shrubs, or vegetable garden. Dig to the depth of the plant roots (3” deep for lawn; 6” deep or more for flowers, vegetables; and 8” deep for trees).

3. Mix the samples together in a plastic pail (do not use a metal pail).

4. If the soil is wet, it will be necessary to air dry the soil. Do not use artificial heat (radiators, ovens, etc.) to force-dry the sample and do not mail wet or damp soil.

5. Place 2-3 cups of the well-mixed soil into the soil box.

6. Mail in your sample to the address included in your test box.


This post is linked to Real Food Wednesday on Kelly the Kitchen Kop, Simple Lives Thursday at GNOWFGLINS and Fight Back Friday at Food Renegade.