The Homeowners Column

The Homeowners Column

Preparing garden soil for planting

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

Spring energizes gardeners and gardener wannabes. The longer, warmer days of spring recharge our solar batteries. Optimism flows through our veins.

The foundation of a good garden is good soil. Soil is highly underappreciated. Soil is not the same as dirt. Dirt is the stuff in your vacuum cleaner bag. Soil is a dynamic substance consisting of minerals, organic matter, insects, fungi, microbes and gazillions of other small creatures. Soil can sustain an oak tree for hundreds of years. Just try growing an oak tree in your vacuum cleaner bag.

Good gardeners know the difference between dirt and soil. This year get to know your soil. First take a good look. A black color indicates high organic matter and we generally like to have 4-6% organic matter in our garden soils. Organic matter is decomposed plants and animals. It adds and retains plant nutrients in the soil. It improves soil structure so air, water and roots can penetrate easily. Organic matter retains moisture and promotes beneficial microbes and animals. Organic matter is good stuff. Compost is a great source of organic matter. Add it to your soil with wild abandon at every opportunity.

A soil test may also be useful to determine the percent organic matter, pH, nutrient levels of phosphorus, potassium and other nutrients such as magnesium and sulfur. The best time for soil testing is in the fall but it can be done in the spring. Do a quick search for soil testing labs in your area.

Never till or work the soil when it is too wet. We all try this and regret it later. If wet soil is worked, its structure (how the soil particles are put together) is destroyed. The result will be clods; not good in men or soil. To determine if it is too wet, squeeze a handful of soil then bounce it in your hand. The soil should fall apart. If it stays in a tight ball, then it is too wet. Sometimes if I just have to get something planted, I do not work the wet soil but use potting soil or compost to cover the seeds or plants.

Take time to control perennial weeds and grass before tilling or planting otherwise the result may be more weeds as each root piece sprouts.

Couple options in controlling perennial weeds:

  • Remove by digging or hoeing.
  • Smother weeds with a cover of several layers of newspaper and mulch. This method is best if you can wait a couple months before planting.
  • A nonselective herbicide such as glyphosate can also be used to kill existing weeds. Once the weeds die in a week or two the soil can be tilled if needed and then planted.

For many gardeners tilling is a rite of spring. New flower or vegetable beds will most likely need to be tilled before planting and is a great way to add compost to the garden.

However, depending on your soil, tilling may not be necessary every year. Existing gardens may have a surface crust but the rest of the soil is fine. For these garden beds just a top dressing of two to three inches of compost may be all that is necessary. Raised beds generally will not need tilling.

Remember tilling brings weed seeds to the surface where they happily germinate competing with your favorite carrots or marigolds. In addition worms don't like it. Tilling destroys worm burrows and probably just doesn't feel too good on their wormy bodies.

The take-home lesson is: get to know your soil then you can make decisions about how to feed the soil that feeds your plants.

Join Champaign County Master Gardeners on Tuesday March 13, 2012 at 7:00pm for the Low Down on Sustainable Lawn Care PH: 217-333-7672.

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