Do you fertilize your lawn? If so, take a moment and ask yourself why you fertilize your lawn? If you come up with any explanation other than "because my soil test indicates that my lawn is lacking specific nutrients" then you are probably wasting time and money on fertilizer.
A soil test provides valuable information about your soil, which is critical information necessary to making proper fertilization decisions. If you apply too much or the wrong kind of fertilizer, it can harm your lawn and can be a complete waste of money. Additionally, fertilizers pollute our water resources – including our streams, bays and our drinking water resources. So why would you or anyone want to use fertilizer if it is unnecessary? And how do you know if it is unnecessary or not? Start by getting your soil tested!
Basic Soil Test: A simple test that provides basic information on pH level and availability of nutrients in your soil (usually tests for nitrogen (N), phosphorous (P) and potassium (K) – which are the three main nutrients in fertilizers).
Specialized Soil Test: A more in depth analysis that provides information about additional nutrients that are available in your soil (may include information on salinity, organic carbon, aluminum, calcium, heavy metals and micronutrients such as copper, iron, manganese, zinc and boron.
Start with a Basic Soil Test!
Simple Steps for Testing Your Soil:
- Trowel or knife or machete
- Clean plastic container
- Clean plastic ziplock bag
- Permanent marker
Step 1: Chose 5-10 representative areas of your yard to take subsamples. The subsample locations should be a representation of the whole area you want to know the soil type (for example, stager sample locations throughout your entire yard area).
Step 2: Clear the subsampling locations of any plant growth or debris.
Step 3: Dig a hole about 4” deep x 4” wide
Step 4: Once the hole is dug, use your shovel to cut away one slice off the side of the hole. Take this slice and using another trowel, knife or machete to cut away the sides, leaving a center section about 1” x 1” wide.
Step 5: Place each of the subsamples into a clean plastic container and mix them together well. Then remove 2 cups of the mixture and put this “composite” sample into a ziplock bag and label the outside of the bag using the permanent marker.
Step 6: The Agricultural Diagnostic Service Center (ADSC) of the College of Tropic Agriculture and Human Resources (CTAHR) at the University of Hawaii at Manoa provides soil sample analysis for about $12. You must fill out the ADSC Soil Sample Information Form and submit it with your soil samples.
Step 7: The final step is to drop off or mail your samples to CTAHR Cooperative Extension Services office: 1910 East-West Road, Room 134, Honolulu, HI 96822.
** Soil analysis results from the ADSC will be returned to you via mail. Results will include raw data, as well as interpretation and recommendations for soil amendments and fertilization needs based on your results. It can take several weeks before the laboratory results are sent back to you, so plan to submit your samples well in advance of when you plan to prepare your soils for planting or fertilizing.
The public is greatly concerned with the use of fertilizers and pesticides for large scale agricultural activities. However, on Oʻahu, with much of our land being urban and suburban, residential use of fertilizers may have a more significant impact to our water resources. Studies show that nutrient levels increase dramatically in areas where streams run through urban and suburban neighborhoods. Increased nutrient levels is most likely the result of over fertilization of residential lawns. Therefore, it is the mission of both HOK and CTAHR to help residents make the right decisions about lawn care and proper fertilization practices that promote a beautiful and healthy lawn, while also protecting Hawaii’s natural resources.
Information for this post provided by CTAHR. Visit the website for more information (http://www.ctahr.hawaii.edu/ougc/soil.asp) or see attached information sheet on “Testing Your Soil: Why and How to Take a Soil-Test Sample.” Additionally you can contact HOK directly or call/email a Master Gardener with any of your questions. http://www.ctahr.hawaii.edu/ate/
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