A soil test is an analysis that determines your garden soil’s nutrient content and pH.
Testing allows you to get a good idea of how well the soil will perform when you place your precious tomato seedlings in its holes. In other words, testing “predicts” how your plants would grow in your particular garden with your particular soil if you did nothing to it.
Once you get the test results, you can amend the soil by adding appropriate nutrients which are deficient. Testing lets you make a much more educated guess about what to work into the soil to make it more tomato-friendly and nutritious.
A good way to understand soil tests is to ask the usual investigative questions: who, what, where, when, why, and how.
Everyone who has a garden.
A kit. Choose between:
Testing with do-it-yourself test kit. The advantage to a kit is convenience – you can test quickly on your own. Many manufacturers offer a variety of soil test kits. You can also use an electronic soil meter to get pH readings and water content. Some electronic meters also check nutrient levels. An electronic meter is a good investment if you’d like to check pH and water levels regularly throughout the season.
Testing through a soil testing lab. Use a local lab if possible, because they will be familiar with soil content in your area. Most charge a small fee to provide you with a soil analysis from your sample. Check with your local cooperative extension service to find out about their soil testing services, obtain a pre-paid soil sample mailer, and get instructions.
It depends what you need. Do-it-yourself kits give you a general idea about your soil’s three major nutrient levels and pH. They are quicker and inexpensive. Rapitest produces one of the most popular home soil test kits.
Other manufacturers offer soil test kits with varying features. Lab tests provide more data than simply pH and the 3 major nutrient readings. They are conducted by professionals and are considered to be more thorough.
Do-it-yourself kits test mostly for three major soil nutrients – nitrogen (N), phosphorus (P), and potassium (K) – and check the soil pH level.
Most lab tests provide three categories of information:
1. Sample’s major nutrients: nitrogen (N), phosphorus (P), and potassium (K)
2. Sample’s secondary nutrients (sulphur, calcium, magnesium) and minor nutrients (iron, manganese, copper, zinc, boron, molybdenum, aluminum)
3. Sample’s pH level. Many lab tests include recommendations for sodium and lime levels. Some offer recommendations for water saturation, too. (You can also get a soil pH kit.)
Just one sample from one hole in the soil will only test that specific bit of soil. To get the best overall reading of your garden plot’s soil, take a composite sample. (See below, HOW should I take a soil sample?)
If possible, conduct the test a few months before growing season so you have time to get results and correct the soil.
If you’ve added lime or fertilizer to your garden, wait 6-8 weeks before testing for most accurate results. Otherwise, nutrient content and pH may be skewed because of the addition of recent amendments.
A composite sample is an “average” of the soil in your entire garden. So you need to get an average!
More on preparing to plant tomatoes in the garden
How to pick the best home garden spot for your tomatoes ...
Preparing your soil for planting tomatoes ...
Tomato transplanting mistakes to avoid when setting out plants ...
Planting tomatoes: how to help your crop succeed in the garden ...
Planting tomato plants: Frequently Asked Questions (FAQs) ...
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