A Fresh Start for Your Garden This Year

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LEFT: The soil tests at Congressional Cemetery’s flower gardens showed a deficiency in the level of nitrate but other nutrients were fine. There are many soil supplements that can be mixed into the soil to resolve the issue.

Why not start the new growing season armed with a plan based on science and real data?  When was the last time you had your soil tested whether in a raised bed, pot, or an acre of land? 

Wouldn’t it be great to know the baseline information on your soil’s pH, nutrient levels, and organic matter content. Soil test results can help you improve your soil’s health and produce the best vegetables and flowers ever. Given the historic multi-use of land on Capitol Hill, if you plan to plant edibles it is important to test the soil for lead and arsenic to make sure it is safe to do so. It is recommended that you test your soil pH and nutrient status every three to five years.

But I Am Not A Scientist!

There is so much information on soil testing that it can make your head spin. Should you buy a soil test kit and test yourself or should you send your soil off to a university or professional lab? Over the past few years, several universities that previously provided soil tests no longer have soil testing labs. But for DC residents, the University of the District of Columbia (UDC) has upgraded its soil lab and is hoping residents will take advantage of what they have to offer.

Kingman Island along the Anacostia River soil was sandier than the soil found in the Hill gardens tested. The Island is a wonderful place to take a hike on a flat path with great views of the river.

Dr. Tolessa Deksissa is the Director of the Water Resources Research Institute and founder and current Director of UDC’s new Environment Quality Testing Laboratory (EQTL). He is an expert in urban soils and water quality assessments. Dr. Deksissa brings a global perspective to his work, having earned his Ph.D. from the Ghent University in Belgium. He says his native home of Ethiopia shares many of the soil qualities of DC and he is keenly interested in getting more DC residents to use the UDC lab to learn more about the soil around them. “It is really about protecting your health, and your family,” says Dr. Deksissa. “It takes about two weeks for the lab to run an extensive report on the nutrients and pH of your soil and the cost ranges from $20 to $50. Besides providing you the data on your soil, the lab will offer suggestions on how to improve the shortfalls.” 

The lab processes about 400 tests a year and has the capacity to increase that number.  The lab is also working on being fully accredited soon. “As often with things in DC, the fact that DC is not truly a state has complicated the accreditation process,” says Tolessa, but he is optimistic this will be resolved. “It really matters only for our larger government contracts and tests, with no effect on a home resident testing their yards or raised beds and pots. We are on our way to being one of the best labs in the country.”

ABOVE: The University of the District Columbia’s scientists gather to discuss findings from the Environmental Quality Testing (EQTL) Laboratory. The lab would like to increase their soil tests for local DC residents. Photo: UDC

If you are interested in getting your soil sampled, go to the UDC website, and fill out the form indicating how much information you are seeking, and you will be sent a quote, more information, and instructions on how to move forward. “Now, is a good time to have your soil tested before things pick up in the spring,” says the Tolessa. The website is https://www.udc.edu/eqtl/request-a-quote/

DIY Test Kits

Sometimes it is easier to just do it yourself. There are several products on the market, and Dr. Deksissa says the tests are about 80 percent accurate, but often they only test the very basic elements of the soil.  I tried one of the leading soil testing kits, Rapitest Digital Soil Test which was recommended by the gardening staff at Homestead Gardens.  The kit cost $42 and has 25 test capsules for pH, nitrogen, phosphorus, and potash. The system uses an advanced LED digital technology and a calibration system. The instructions are easy to follow.  But it is a time-consuming process, and results probably rely on how carefully one handles the soil, the capsules, and water.

There is a lot of waiting time, which contributes to the time professional labs take. The soil must be dried out after it is collected, and then it must be filtered.

Once a cup of soil is collected by digging several inches down into the soil, it must be filtered to make a fine sample. The soil is mixed with distilled water, available at Frager’s Hardware.  It can take several hours to 24 hours for the soil mix to settle and be ready to transfer to test tubs where the appropriate powder is added. Then, ten minutes later it is time to find out the results which are displayed on a digital LED indicator.  Most of the other soil tests work similarly. Testing at home gives you latitude of where and when you test. If you have a plant that is not thriving, it may be a quick way to analyze the problem and take some of the guess work out of gardening.

Homestead Gardens in Davidsonville, Maryland, recommends the digital soil testing system called Rapitest. It costs $42.

Test Results Around the Hill

Are you curious about how different the soil is around the Hill? I did a spot test on three locations.  My garden at 11th and East Capitol, a picnic spot on Kingman Island near the Anacostia River, and some soil from the Congressional Cemetery. My front yard garden, which had soil improvement last summer, registered in the adequate range in nitrogen, potash, and phosphorus. The pH level was a little high at 7.5, leaving some room for adjustment before planting this summer.

The Kingman Island sample also showed a pH level of 7.5. The nitrogen level was sufficient, but potash and phosphorous were in the surplus range. This may influence some of the tree growth along the river, but it seemed to have little effect on the ground growth. 

The Congressional Cemetery at 1801 E Street, SE is a popular spot among Hill residents and dog owners. There are flower gardens that welcome visitors to the historical site. The soil sample was taken from an area under a tree next to the main administrative building and gift shop. Unlike the two other samples, the Congressional Cemetery flower garden was much lower in pH at 6.5 and turned up depleted in the nitrogen reading. Its potash was sufficient and its phosphorous adequate.   

If you are the DIY type, there are many good home soil tests on the market. After filtering the soil and adding the appropriate test powders, using a dropper provided by the soil kit, soil liquid is placed into the test tubes.

February and March are perfect times to take soil samples and run tests on the health of your garden soils. It will let you have time to make improvements to the soil before you start planting in the spring. Put on your white lab coat, and get to testing, you won’t regret it.

Rindy O’Brien highly recommends a soil test, and is very pleased that UDC has a great program for all to use. To contact Rindy – rindyobrien@gmail.com