AgroTips: September

By on September 9, 2010

Monthly advice from the NCDA&CS Agronomic Division for farmers and homeowners for maintaining healthy soil.

SoilPrepare gardens for fall/winter.

First, if you haven’t had your soil tested in the last three years, do it now. Instructions for collecting samples are online at If you are a North Carolina resident, this is a free test. Act now because after October the lab will begin receiving end-of-season samples from farmers, and the wait for reports will be much longer.

If your report indicates that lime should be applied to raise soil pH, don’t delay. Winter soil is usually moist and helps lime neutralize soil acidity before spring planting. However, don’t add lime unless the soil report recommends it. Excess lime can make some nutrients unavailable to plants.

Second, consider protecting garden soils by planting a cover crop or putting out mulch. Legumes—such as crimson clover, hairy vetch, Austrian winter pea—add nitrogen to the soil as well as organic matter when they decompose in the spring. In addition, crimson clover is a beautiful sight when it blooms. Another option is to plant greens such as mustard or kale and enjoy eating the small leaves as they grow.

If you don’t plant a cover crop, you should apply a 2-inch layer of mulch, such as composted leaf material, shredded or chipped pine bark, or pine needles. Straw can also be used if it is good quality without weed seeds. The mulch should be thick enough to reduce weed seed germination and retain soil moisture without impeding adequate water and air movement.

Once you have made these preparations, do not apply fertilizer until spring unless you are planting a fall vegetable garden. In that case, you can still follow these suggestions (even sowing a cover crop around the vegetable beds), but you will also need to apply fertilizer as recommended on your soil test report.

Test your bulk soilless potting media before planting greenhouse crops.

Before planting greenhouse crops, propagating woody plants or beginning seasonal flower production, commercial producers should sample and test the bulk soilless media they plan to grow their plants in. The procedure, known as saturated media extract (SME), measures nutrient concentration, electrical conductivity and pH. The cost is $5 per sample for N.C. residents and $25 for out-of-state residents, and test results are available online two working days after samples are checked in to the laboratory. Sampling instructions and sample information forms can be found online at

For more information, contact or visit the NCDA&CS Agronomic Division:

Physical Address — 4300 Reedy Creek Road, Raleigh NC 27607-6465
Mailing Address — 1040 Mail Service Center, Raleigh NC 27699-1040
Phone — (919) 733-2655
Website —

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  1. broken link
    September 9, 2010

    the link for soil testing instructions is correct as it appears, but the hyperlink is not. just wanted to let you know.

  2. Paul Jones
    September 10, 2010

    Thanks. The links should work now.

  3. Frogger Games
    September 13, 2010

    Shoot, I have to test it even more frequently than every 3 years. I couldn’t believe the acidity of the soil I was using when I last checked it. Great for some species, but overall it didn’t have nearly enough nutrients to support most vegetables or flowers. Test often and you’ll be much better off.

  4. Singing Machine Karaoke
    September 14, 2010

    When we put our mulch in in the summer, I usually do a quick test to make sure that everything is ok. We live near a couple power plants so you never know. Probably unneeded anal retentiveness talking, but it keeps me testing the soil. haha