The Dirt--Preparing for spring

Date Published: 
February 24, 2012

OK, gardeners – put down the plant catalogs and step away from the Internet. It’s time to get to work! You need to get your soil into shape.

As every gardener knows, a good garden begins with good soil. Preparing your soil for the coming season is basically three steps: clean-up, testing and amending the soil with nutrients. By completing these steps, you give your garden the best possible chance for optimal production.

Clean-up, the first step, is a no-brainer. Most people do it simply for the aesthetics. But don’t underestimate the benefits it provides for plant health. Removing old plant debris from ornamental beds or vegetable gardens greatly reduces the risk of fungal diseases and other pests.

Plants such as roses or photinias, which are vulnerable to leaf-spot diseases, especially benefit from having fallen leaves raked up. Those fallen leaves may contain spores that can re-infect this year’s new growth. So get out there on one of these warm days we’ve been enjoying, and clear out the vegetable beds and rake up around the shrubs.

The next step to a productive garden is soil testing. I cannot emphasize enough how important this is. We all want good fertile soil, but throwing fertilizer on it randomly can be more harmful than helpful. Our fragile Inland Bays have been stressed to near exhaustion by an excess of nutrients, and since we all drain into the bays eventually, it is up to us to use fertilizers wisely.

And as the old song said, “You can’t know what you want ’til you find out what you need.” A soil test is designed to inform you of what you need and, just as importantly, what you don’t need. Much of our local soil is especially high in phosphorus, so any additional phosphorus applied is going to wind up in local waters. By having your soil tested before applying fertilizer, you can save money in unnecessary applications and reduce stress on the local environment. Definitely a win-win situation.

The University of Delaware’s College of Agriculture provides inexpensive soil testing services to home gardeners. Soil sampling kits are available at the county extension office or at some garden centers, including Lord’s Landscaping. For $10, they will provide an analysis showing the pH, available nutrients and organic matter content. In addition, the results come with recommendations based on the crop you are growing, such as vegetables, ornamentals or lawns.

The pH test measures the soil’s acidity and guides you to the optimum level for the type of plant you are growing. Some plants, such as strawberries or blueberries, prefer a low pH and react poorly to the addition of lime. Others, like turf grass, prefer a higher pH and struggle at lower levels. Having an accurate picture of your soil’s pH will point you to the optimal level for your garden.

The nutrient results of the test are given in Fertility Index Values and are listed as either low, medium, optimum or excessive. A low rating means that it is highly likely to get a positive plant response to the addition of that nutrient. A medium rating means that there will likely be a moderate benefit to adding more of the nutrient.

At the optimum level, the plant has all of the nutrient that it needs available already, and you’d be wasting your money by adding more. An excessive rating means further applications could have undesirable effects. Knowing your nutrient levels allows you to fine-tune your fertilizer use to what your plants need without the addition of things that they don’t.

The organic matter portion of the test gives a general indication of the tilth, or quality of the soil. Usually, the higher the organic content of the soil, the better the aeration and capacity to hold water and nutrients.

Unfortunately, as anyone who has ever stuck a shovel in our local soil knows, we’re not great on the organic thing. While the ideal soil is described as sandy loam, what we have is loamy sand. Or, in some places, just sand. Adding organic matter, through compost or manure, improves just about everything in your soil’s structure.

Be sure to follow the instructions in the kit to get a good representative sampling. If you are growing different types of plants in different areas, such as a lawn in one area and ornamentals or vegetables in another, you will need to do separate tests for each, since they will have different requirements and recommendations.

Once you have your test results, you’re ready for step three, amending the soil. Limestone, for adjusting the pH, is slow to react in the soil, so apply it as early as possible.

Recommended nutrients can be applied as slow-acting or quick-release forms, according to your preference. If your organic content is low, bagged compost or cow manure are readily available at most garden centers. And there are horse owners locally that are only too happy to load you up with good horse manure.

So now you know what you need to do. Following these steps will put your garden in the best possible position for a season of beauty and productivity.

Ginger Hogan is a Delaware Certified Nursery Professional. Do you have questions you’d like to have answered in a future column? Send them to Ginger at