{"id":4007,"date":"2022-06-08T10:50:17","date_gmt":"2022-06-08T08:50:17","guid":{"rendered":"https:\/\/www.plantcaretools.com\/?page_id=4007"},"modified":"2026-11-10T20:16:52","modified_gmt":"2026-11-10T19:16:52","slug":"measure-nutrients-level-soil","status":"publish","type":"page","link":"https:\/\/www.plantcaretools.com\/en\/measure-nutrients-level-soil\/","title":{"rendered":"NPK soil test"},"content":{"rendered":"\n<div class=\"pct-kb-hero\">\n<svg class=\"pct-kb-leaf\" viewBox=\"0 0 200 300\" aria-hidden=\"true\"><path fill=\"#2d5a27\" d=\"M100 5C30 70 10 170 100 295 190 170 170 70 100 5Z\"\/><path stroke=\"#eaf4e8\" stroke-width=\"4\" fill=\"none\" d=\"M100 20V290M100 90l-40-30M100 140l-55-35M100 190l-55-30M100 90l40-30M100 140l55-35M100 190l55-30\"\/><\/svg>\n<div class=\"pct-kb-hero-inner\">\n<div class=\"pct-kb-hero-left\">\n<div class=\"pct-kb-badge\">Knowledge base \u00b7 NPK soil test<\/div>\n<h1 class=\"pct-kb-title\">NPK soil test: which <span class=\"pct-accent\">nutrients<\/span> is your soil missing?<\/h1>\n<p class=\"pct-kb-desc\">An NPK soil test tells you whether there is enough nitrogen, phosphorus and potassium in the soil. Here you\u2019ll learn to spot deficiencies on the leaves, which test method to choose and how to take a good soil sample.<\/p>\n<div class=\"pct-kb-meta\"><span><b>Updated<\/b> 2026<\/span><span><b>Reading time<\/b> 5 minutes<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n<style>\n.pct-kb-hero,.pct-kb-hero *{box-sizing:border-box}\n.pct-kb-hero{width:100vw;max-width:100vw;margin-left:calc(-50vw + 50%);margin-right:calc(-50vw + 50%);margin-top:0;background:linear-gradient(135deg,#eaf4e8 0%,#d6edcc 60%,#c5e8be 100%);padding:56px 5% 64px;position:relative;overflow:hidden}\n.pct-kb-hero-inner{max-width:1100px;margin:0 auto;display:flex;align-items:center;gap:48px;position:relative;z-index:1}\n.pct-kb-hero-left{flex:1 1 440px;min-width:0}\n.pct-kb-leaf{position:absolute;left:-150px;top:50%;transform:translateY(-50%) 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(max-width:767px){.pct-kb figure.pct-kb-img{max-width:220px}.pct-kb figure.pct-kb-img img{max-height:200px}}\n<\/style>\n<script>(function(){function l(){document.querySelectorAll(\".pct-kb-table table\").forEach(function(t){var h=[].map.call(t.querySelectorAll(\"thead th\"),function(x){return x.textContent.trim()});t.querySelectorAll(\"tbody tr\").forEach(function(r){[].forEach.call(r.children,function(c,i){if(h[i])c.setAttribute(\"data-label\",h[i])})})})}if(document.readyState!==\"loading\")l();else document.addEventListener(\"DOMContentLoaded\",l)})();<\/script>\n<script type=\"application\/ld+json\" id=\"pct-kb-faq-schema\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"@id\":\"https:\/\/www.plantcaretools.com\/en\/measure-nutrients-level-soil\/#faq\",\"inLanguage\":\"en\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"What does NPK mean?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"NPK stands for the three main plant nutrients: nitrogen (N), phosphorus (P) and potassium (K). On a fertiliser pack you see the ratio, for example 10-5-15.\"}},{\"@type\":\"Question\",\"name\":\"How do you test NPK in soil?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"With a soil test kit: you mix a soil sample with water and a reagent and compare the colour with a chart. An electronic NPK meter is pushed straight into the soil. The most accurate option is a laboratory soil test (Montana State University).\"}},{\"@type\":\"Question\",\"name\":\"How reliable is an electronic NPK meter?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"An electronic NPK meter gives a quick indication and is handy for comparing spots. For exact values per nutrient and full fertiliser advice, use a soil test kit or have the soil tested by a laboratory.\"}},{\"@type\":\"Question\",\"name\":\"Is a soil test kit reliable?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"It depends on the kit. In a comparison, simple kits differed moderately to strongly from the laboratory; the best kit, where you dry and grind the soil, came close to lab values (Montana State University). So follow the instructions precisely.\"}},{\"@type\":\"Question\",\"name\":\"What does nitrogen deficiency look like?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"General yellowing of the older, lower leaves, while the rest of the plant is light green (University of Arizona).\"}},{\"@type\":\"Question\",\"name\":\"What does potassium deficiency look like?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Older leaves wilt and look scorched, with yellowing between the veins that moves inward from the leaf edge (University of Arizona).\"}},{\"@type\":\"Question\",\"name\":\"What does phosphorus deficiency look like?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Leaf tips look burnt, and then older leaves turn dark green to reddish-purple (University of Arizona).\"}},{\"@type\":\"Question\",\"name\":\"How do you take a soil sample?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"For a lawn, sample to 7.5 cm (3 in); in vegetable gardens and beds, to 15\u201320 cm (6\u20138 in). Take soil from several spots and mix it: 4 to 6 spots in a border, 10 to 15 in a larger garden (Purdue University).\"}},{\"@type\":\"Question\",\"name\":\"How often should you test your soil?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"For a garden, every 3 to 5 years is enough (Purdue University). Pot plants use up nutrients faster; track them with an EC meter after feeding.\"}},{\"@type\":\"Question\",\"name\":\"When should you have soil tested by a lab?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"When you want exact fertiliser advice, for a large vegetable garden, or when plants keep struggling even though you feed them. A laboratory measures each nutrient separately and gives advice (Montana State University).\"}}]}<\/script>\n\n\n\n<div class=\"wp-block-group pct-kb is-layout-flow wp-block-group-is-layout-flow\"><span><span><a href=\"https:\/\/www.plantcaretools.com\/en\/\">Home<\/a><\/span><\/span>\n\n\n\n<h2 class=\"wp-block-heading\">Why do an NPK soil test?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Plants mainly need a lot of nitrogen (N), phosphorus (P) and potassium (K), together called NPK. They also use smaller amounts of magnesium and trace elements such as iron. In a pot, nutrients also run out faster than in open ground, because the roots have little soil. That\u2019s why you feed pot plants while they grow, usually from March to October (University of Connecticut).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">An EC meter shows how much nutrient there is in total, but not which one (USDA NRCS). If you want to know whether nitrogen, phosphorus or potassium is missing, you do an NPK soil test. Read more about the difference under <a href=\"https:\/\/www.plantcaretools.com\/en\/fertilizing-plants-faq\/\">EC meter for plants<\/a>.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large pct-kb-img\"><img decoding=\"async\" src=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/07\/STK008-display.jpg\" alt=\"NPK soil test with a soil test kit for nitrogen, phosphorus, potassium and pH\"\/><figcaption class=\"wp-element-caption\">A soil test kit measures nitrogen, phosphorus, potassium and pH.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Spotting deficiencies on the leaves<\/h2>\n\n\n\n<figure class=\"wp-block-table pct-kb-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Deficiency<\/th><th>Where<\/th><th>What you see<\/th><\/tr><\/thead><tbody><tr><td>Nitrogen (N)<\/td><td>Older, lower leaves<\/td><td>General yellowing; the rest of the plant is light green<\/td><\/tr><tr><td>Phosphorus (P)<\/td><td>Leaf tips, then older leaves<\/td><td>Burnt tips, then dark green to reddish-purple leaves<\/td><\/tr><tr><td>Potassium (K)<\/td><td>Older leaves<\/td><td>Wilting and scorching from the leaf edge inward<\/td><\/tr><tr><td>Magnesium (Mg)<\/td><td>Older leaves<\/td><td>Yellow leaf edge with a green arrowhead in the centre<\/td><\/tr><tr><td>Iron (Fe)<\/td><td>Young leaves<\/td><td>Yellowing between the veins<\/td><\/tr><\/tbody><\/table><figcaption class=\"wp-element-caption\">Source: University of Arizona. Symptoms can look alike or resemble disease and drought; testing gives certainty.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">NPK soil test: test kit, electronic meter or laboratory?<\/h2>\n\n\n\n<figure class=\"wp-block-table pct-kb-table pct-kb-compare\"><table class=\"has-fixed-layout\"><thead><tr><th><\/th><th>Soil test kit<\/th><th>Electronic NPK meter<\/th><th>Laboratory<\/th><\/tr><\/thead><tbody><tr><td>How<\/td><td>Sample with water and reagent, compare colour<\/td><td>Push the meter into the soil<\/td><td>Send off a sample<\/td><\/tr><tr><td>Result<\/td><td>Low, medium or high per nutrient<\/td><td>A number, instantly<\/td><td>Exact values with fertiliser advice<\/td><\/tr><tr><td>Accuracy<\/td><td>Varies, from moderate to good<\/td><td>Quick indication, handy for comparing<\/td><td>Most accurate<\/td><\/tr><tr><td>Best for<\/td><td>Vegetable garden, lawn, borders<\/td><td>Quick checks in several spots, no chemicals<\/td><td>Large garden, persistent problems<\/td><\/tr><tr><td>Example<\/td><td><a href=\"https:\/\/www.plantcaretools.com\/en\/soil-test-kit-n-p-k-ph\/\">Soil test kit N, P, K, pH<\/a><\/td><td><a href=\"https:\/\/www.plantcaretools.com\/en\/10-in-1-soil-tester-npk-ph-ec\/\">10-in-1 soil tester<\/a><\/td><td>\u2013<\/td><\/tr><\/tbody><\/table><figcaption class=\"wp-element-caption\">Test kits: Montana State University (2019).<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">An electronic NPK meter is quick and easy: push it in, read it, done, without chemicals. You immediately see where in your garden or pot nutrient levels are higher or lower. If you want to know exactly how much of each nutrient is in the soil, use a <a href=\"https:\/\/www.plantcaretools.com\/en\/soil-test-kit-n-p-k-ph\/\">soil test kit<\/a> and follow the instructions precisely, because simple kits can otherwise differ quite a bit from the laboratory (Montana State University). For full fertiliser advice, have the soil tested by a laboratory.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">NPK soil test in 4 steps<\/h2>\n\n\n\n<ol class=\"wp-block-list pct-kb-steps\">\n<li><strong>Sample at root depth.<\/strong> For a lawn to 7.5 cm (3 in), in vegetable gardens and borders to 15\u201320 cm (6\u20138 in) (Purdue University). For pot plants, take soil from the middle of the pot.<\/li>\n\n\n\n<li><strong>Mix several spots.<\/strong> Take soil from 4 to 6 spots in a border or 10 to 15 in a larger garden and mix it (Purdue University). Remove stones and roots.<\/li>\n\n\n\n<li><strong>Follow the instructions precisely.<\/strong> With a test kit, the amounts of soil and water and the waiting time determine the result. You can find the manuals under <a href=\"https:\/\/www.plantcaretools.com\/en\/download-manuals\/\">download manuals<\/a>.<\/li>\n\n\n\n<li><strong>Write it down and repeat.<\/strong> Test a garden every 3 to 5 years (Purdue University). Also check the <a href=\"https:\/\/www.plantcaretools.com\/en\/measure-ph-level-soil\/\">soil pH<\/a>, because at the wrong pH plants struggle to take up nutrients.<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Keeping track of nutrients in potting mix<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In pot plants, nutrient levels change faster than in the garden. An EC meter or the <a href=\"https:\/\/www.plantcaretools.com\/en\/fertometer-measures-fertilisation-and-gives-advice-plantcaretools\/\">Fertometer<\/a> is handy here: after feeding, you see whether nutrients have been added and whether they drop away again. If you see brown leaf tips, wilting or a white crust on the pot rim, there has probably been too much fertiliser (University of Connecticut). Flush the pot well with water.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Our picks for an NPK soil test<\/h2>\n\n\n<div data-block-name=\"woocommerce\/handpicked-products\" data-columns=\"4\" data-content-visibility=\"{&quot;title&quot;:true,&quot;price&quot;:true,&quot;rating&quot;:false,&quot;button&quot;:false}\" data-orderby=\"menu_order\" data-products=\"[5466,5626,17460,24094]\" class=\"wc-block-grid wp-block-handpicked-products wp-block-woocommerce-handpicked-products wc-block-handpicked-products has-4-columns has-multiple-rows\"><ul class=\"wc-block-grid__products\"><li class=\"wc-block-grid__product\"><span class=\"gtm4wp_productdata\" style=\"display:none; visibility:hidden;\" data-gtm4wp_product_data=\"{&quot;internal_id&quot;:24094,&quot;item_id&quot;:&quot;24094&quot;,&quot;item_name&quot;:&quot;10-in-1 Soil Tester \\u2013 NPK, pH, EC, Moisture, Temperature &amp; Light&quot;,&quot;sku&quot;:&quot;PCT091&quot;,&quot;price&quot;:119.9,&quot;stocklevel&quot;:null,&quot;stockstatus&quot;:&quot;instock&quot;,&quot;google_business_vertical&quot;:&quot;retail&quot;,&quot;item_category&quot;:&quot;Measuring Instruments&quot;,&quot;id&quot;:&quot;24094&quot;,&quot;productlink&quot;:&quot;https:\\\/\\\/www.plantcaretools.com\\\/en\\\/10-in-1-soil-tester-npk-ph-ec\\\/&quot;,&quot;item_list_name&quot;:&quot;General Product List&quot;,&quot;index&quot;:0,&quot;product_type&quot;:&quot;simple&quot;,&quot;item_list_id&quot;:&quot;general-product-list&quot;,&quot;item_brand&quot;:&quot;&quot;}\"><\/span>\n\t\t\t\t<a href=\"https:\/\/www.plantcaretools.com\/en\/10-in-1-soil-tester-npk-ph-ec\/\" class=\"wc-block-grid__product-link\">\n\t\t\t\t\t\n\t\t\t\t\t<div class=\"wc-block-grid__product-image\"><img loading=\"lazy\" decoding=\"async\" width=\"272\" height=\"272\" src=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond-272x272.jpg\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"10-in-1 bodemtester in de potgrond van een kamerplant met pH, vocht en temperatuur op het display\" srcset=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond-272x272.jpg 272w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond-300x300.jpg 300w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond-1024x1024.jpg 1024w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond-150x150.jpg 150w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond-768x768.jpg 768w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond-600x600.jpg 600w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond-100x100.jpg 100w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2026\/09\/10-in-1-bodemtester-kamerplant-potgrond.jpg 1200w\" sizes=\"auto, (max-width: 272px) 100vw, 272px\" data-wp-pid=\"24098\" \/><\/div>\n\t\t\t\t\t<div class=\"wc-block-grid__product-title\">10-in-1 Soil Tester \u2013 NPK, pH, EC, Moisture, Temperature &amp; Light<\/div>\n\t\t\t\t<\/a>\n\t\t\t\t<div class=\"wc-block-grid__product-price price\"><span class=\"woocommerce-Price-amount amount\"><bdi><span class=\"woocommerce-Price-currencySymbol\" dir=\"auto\">&euro;<\/span>119,90<\/bdi><\/span><\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/li><li class=\"wc-block-grid__product\"><span class=\"gtm4wp_productdata\" style=\"display:none; visibility:hidden;\" data-gtm4wp_product_data=\"{&quot;internal_id&quot;:17460,&quot;item_id&quot;:&quot;17460&quot;,&quot;item_name&quot;:&quot;EC-TDS-TEMPERATURE Soil meter (Bluetooth)&quot;,&quot;sku&quot;:&quot;PCT121&quot;,&quot;price&quot;:39.9,&quot;stocklevel&quot;:-2,&quot;stockstatus&quot;:&quot;outofstock&quot;,&quot;google_business_vertical&quot;:&quot;retail&quot;,&quot;item_category&quot;:&quot;Producten&quot;,&quot;id&quot;:&quot;17460&quot;,&quot;productlink&quot;:&quot;https:\\\/\\\/www.plantcaretools.com\\\/en\\\/ec-tds-temperature-soil-meter\\\/&quot;,&quot;item_list_name&quot;:&quot;General Product List&quot;,&quot;index&quot;:0,&quot;product_type&quot;:&quot;simple&quot;,&quot;item_list_id&quot;:&quot;general-product-list&quot;,&quot;item_brand&quot;:&quot;&quot;}\"><\/span>\n\t\t\t\t<a href=\"https:\/\/www.plantcaretools.com\/en\/ec-tds-temperature-soil-meter\/\" class=\"wc-block-grid__product-link\">\n\t\t\t\t\t\n\t\t\t\t\t<div class=\"wc-block-grid__product-image\"><img loading=\"lazy\" decoding=\"async\" width=\"272\" height=\"272\" src=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2024\/01\/IMG_3379-272x272.jpeg\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"EC-TDS-TEMPERATURE Soil meter (Bluetooth)\" srcset=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2024\/01\/IMG_3379-272x272.jpeg 272w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2024\/01\/IMG_3379-300x300.jpeg 300w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2024\/01\/IMG_3379-150x150.jpeg 150w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2024\/01\/IMG_3379-768x768.jpeg 768w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2024\/01\/IMG_3379-600x600.jpeg 600w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2024\/01\/IMG_3379-100x100.jpeg 100w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2024\/01\/IMG_3379.jpeg 960w\" sizes=\"auto, (max-width: 272px) 100vw, 272px\" data-wp-pid=\"17461\" \/><\/div>\n\t\t\t\t\t<div class=\"wc-block-grid__product-title\">EC-TDS-TEMPERATURE Soil meter (Bluetooth)<\/div>\n\t\t\t\t<\/a>\n\t\t\t\t<div class=\"wc-block-grid__product-price price\"><span class=\"woocommerce-Price-amount amount\"><bdi><span class=\"woocommerce-Price-currencySymbol\" dir=\"auto\">&euro;<\/span>39,90<\/bdi><\/span><\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/li><li class=\"wc-block-grid__product\"><span class=\"gtm4wp_productdata\" style=\"display:none; visibility:hidden;\" data-gtm4wp_product_data=\"{&quot;internal_id&quot;:5466,&quot;item_id&quot;:&quot;5466&quot;,&quot;item_name&quot;:&quot;Soil Test Kit (N, P, K, pH) 80 Tests&quot;,&quot;sku&quot;:&quot;PCT210&quot;,&quot;price&quot;:68.9,&quot;stocklevel&quot;:97,&quot;stockstatus&quot;:&quot;instock&quot;,&quot;google_business_vertical&quot;:&quot;retail&quot;,&quot;item_category&quot;:&quot;Measuring Instruments&quot;,&quot;id&quot;:&quot;5466&quot;,&quot;productlink&quot;:&quot;https:\\\/\\\/www.plantcaretools.com\\\/en\\\/soil-test-kit-n-p-k-ph\\\/&quot;,&quot;item_list_name&quot;:&quot;General Product List&quot;,&quot;index&quot;:0,&quot;product_type&quot;:&quot;simple&quot;,&quot;item_list_id&quot;:&quot;general-product-list&quot;,&quot;item_brand&quot;:&quot;&quot;}\"><\/span>\n\t\t\t\t<a href=\"https:\/\/www.plantcaretools.com\/en\/soil-test-kit-n-p-k-ph\/\" class=\"wc-block-grid__product-link\">\n\t\t\t\t\t\n\t\t\t\t\t<div class=\"wc-block-grid__product-image\"><img loading=\"lazy\" decoding=\"async\" width=\"272\" height=\"272\" src=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/08\/STK008-KIT-DANALYSE-DE-SOL-272x272.jpg\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Soil Test Kit - Grondtestkit - N P K pH Testen - Plant Care Tools\" srcset=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/08\/STK008-KIT-DANALYSE-DE-SOL-272x272.jpg 272w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/08\/STK008-KIT-DANALYSE-DE-SOL-100x100.jpg 100w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/08\/STK008-KIT-DANALYSE-DE-SOL-600x600.jpg 600w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/08\/STK008-KIT-DANALYSE-DE-SOL-300x300.jpg 300w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/08\/STK008-KIT-DANALYSE-DE-SOL-150x150.jpg 150w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/08\/STK008-KIT-DANALYSE-DE-SOL-768x768.jpg 768w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2022\/08\/STK008-KIT-DANALYSE-DE-SOL.jpg 800w\" sizes=\"auto, (max-width: 272px) 100vw, 272px\" data-wp-pid=\"6775\" \/><\/div>\n\t\t\t\t\t<div class=\"wc-block-grid__product-title\">Soil Test Kit (N, P, K, pH) 80 Tests<\/div>\n\t\t\t\t<\/a>\n\t\t\t\t<div class=\"wc-block-grid__product-price price\"><span class=\"woocommerce-Price-amount amount\"><bdi><span class=\"woocommerce-Price-currencySymbol\" dir=\"auto\">&euro;<\/span>68,90<\/bdi><\/span><\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/li><li class=\"wc-block-grid__product\"><span class=\"gtm4wp_productdata\" style=\"display:none; visibility:hidden;\" data-gtm4wp_product_data=\"{&quot;internal_id&quot;:5626,&quot;item_id&quot;:&quot;5626&quot;,&quot;item_name&quot;:&quot;Fertometer: measures fertilisation and gives advice&quot;,&quot;sku&quot;:&quot;PCT030&quot;,&quot;price&quot;:25.9,&quot;stocklevel&quot;:54,&quot;stockstatus&quot;:&quot;instock&quot;,&quot;google_business_vertical&quot;:&quot;retail&quot;,&quot;item_category&quot;:&quot;Measuring Instruments&quot;,&quot;id&quot;:&quot;5626&quot;,&quot;productlink&quot;:&quot;https:\\\/\\\/www.plantcaretools.com\\\/en\\\/fertometer-measures-fertilisation-and-gives-advice-plantcaretools\\\/&quot;,&quot;item_list_name&quot;:&quot;General Product List&quot;,&quot;index&quot;:0,&quot;product_type&quot;:&quot;simple&quot;,&quot;item_list_id&quot;:&quot;general-product-list&quot;,&quot;item_brand&quot;:&quot;&quot;}\"><\/span>\n\t\t\t\t<a href=\"https:\/\/www.plantcaretools.com\/en\/fertometer-measures-fertilisation-and-gives-advice-plantcaretools\/\" class=\"wc-block-grid__product-link\">\n\t\t\t\t\t\n\t\t\t\t\t<div class=\"wc-block-grid__product-image\"><img loading=\"lazy\" decoding=\"async\" width=\"272\" height=\"272\" src=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-272x272.jpg\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Fertometer: measures fertilisation and gives advice\" srcset=\"https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-272x272.jpg 272w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-300x300.jpg 300w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-1024x1024.jpg 1024w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-150x150.jpg 150w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-768x768.jpg 768w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-1536x1536.jpg 1536w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-2048x2048.jpg 2048w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-600x600.jpg 600w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-100x100.jpg 100w, https:\/\/www.plantcaretools.com\/wp-content\/uploads\/2017\/08\/plantcarekit_ph_temperature_moisture_light_nutrients_plantcaretools5-scaled-1200x1200.jpg 1200w\" sizes=\"auto, (max-width: 272px) 100vw, 272px\" data-wp-pid=\"20637\" \/><\/div>\n\t\t\t\t\t<div class=\"wc-block-grid__product-title\">Fertometer: measures fertilisation and gives advice<\/div>\n\t\t\t\t<\/a>\n\t\t\t\t<div class=\"wc-block-grid__product-price price\"><span class=\"woocommerce-Price-amount amount\"><bdi><span class=\"woocommerce-Price-currencySymbol\" dir=\"auto\">&euro;<\/span>25,90<\/bdi><\/span><\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/li><\/ul><\/div>\n\n\n<h2 class=\"wp-block-heading\">Frequently asked questions about NPK soil tests<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">NPK soil test<\/h3>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>What does NPK mean?<\/summary>\n<p class=\"wp-block-paragraph\">NPK stands for the three main plant nutrients: nitrogen (N), phosphorus (P) and potassium (K). On a fertiliser pack you see the ratio, for example 10-5-15.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>How do you test NPK in soil?<\/summary>\n<p class=\"wp-block-paragraph\">With a soil test kit: you mix a soil sample with water and a reagent and compare the colour with a chart. An electronic NPK meter is pushed straight into the soil. The most accurate option is a laboratory soil test (Montana State University).<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>How reliable is an electronic NPK meter?<\/summary>\n<p class=\"wp-block-paragraph\">An electronic NPK meter gives a quick indication and is handy for comparing spots. For exact values per nutrient and full fertiliser advice, use a soil test kit or have the soil tested by a laboratory.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>Is a soil test kit reliable?<\/summary>\n<p class=\"wp-block-paragraph\">It depends on the kit. In a comparison, simple kits differed moderately to strongly from the laboratory; the best kit, where you dry and grind the soil, came close to lab values (Montana State University). So follow the instructions precisely.<\/p>\n<\/details>\n\n\n\n<h3 class=\"wp-block-heading\">Spotting deficiencies<\/h3>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>What does nitrogen deficiency look like?<\/summary>\n<p class=\"wp-block-paragraph\">General yellowing of the older, lower leaves, while the rest of the plant is light green (University of Arizona).<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>What does potassium deficiency look like?<\/summary>\n<p class=\"wp-block-paragraph\">Older leaves wilt and look scorched, with yellowing between the veins that moves inward from the leaf edge (University of Arizona).<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>What does phosphorus deficiency look like?<\/summary>\n<p class=\"wp-block-paragraph\">Leaf tips look burnt, and then older leaves turn dark green to reddish-purple (University of Arizona).<\/p>\n<\/details>\n\n\n\n<h3 class=\"wp-block-heading\">Soil sample and laboratory<\/h3>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>How do you take a soil sample?<\/summary>\n<p class=\"wp-block-paragraph\">For a lawn, sample to 7.5 cm (3 in); in vegetable gardens and beds, to 15\u201320 cm (6\u20138 in). Take soil from several spots and mix it: 4 to 6 spots in a border, 10 to 15 in a larger garden (Purdue University).<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>How often should you test your soil?<\/summary>\n<p class=\"wp-block-paragraph\">For a garden, every 3 to 5 years is enough (Purdue University). Pot plants use up nutrients faster; track them with an EC meter after feeding.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details pct-kb-faq is-layout-flow wp-block-details-is-layout-flow\"><summary>When should you have soil tested by a lab?<\/summary>\n<p class=\"wp-block-paragraph\">When you want exact fertiliser advice, for a large vegetable garden, or when plants keep struggling even though you feed them. A laboratory measures each nutrient separately and gives advice (Montana State University).<\/p>\n<\/details>\n\n\n\n<p class=\"wp-block-paragraph\">Measuring in water too? Read about the <a href=\"https:\/\/www.plantcaretools.com\/en\/measure-ec-water\/\">EC of water<\/a>. Everything about feeding and EC is under <a href=\"https:\/\/www.plantcaretools.com\/en\/fertilizing-plants-faq\/\">EC meter for plants<\/a>.<\/p>\n\n\n\n<div class=\"wp-block-group pct-kb-cta is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\">Not sure which meter suits you?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Tell us what you want to measure: pot plants, vegetable garden or lawn. We\u2019ll help you choose the right test kit or meter, free of charge.<\/p>\n\n\n\n<div class=\"pct-kb-btns\"><a class=\"pct-kb-btn\" href=\"https:\/\/www.plantcaretools.com\/en\/measuring-instruments\/\">View measuring instruments<\/a><a class=\"pct-kb-btn alt\" href=\"https:\/\/www.plantcaretools.com\/en\/contact\/\">Ask for free advice<\/a><\/div>\n<\/div>\n\n\n\n<h3 class=\"wp-block-heading\">Sources<\/h3>\n\n\n\n<ul class=\"wp-block-list pct-kb-sources\">\n<li><a href=\"https:\/\/www.extension.arizona.edu\/publication\/guide-symptoms-plant-nutrient-deficiencies\" rel=\"noopener\">Bradley &#038; Hosier, Guide to Symptoms of Plant Nutrient Deficiencies, University of Arizona<\/a>: spotting deficiencies on the leaves<\/li>\n\n\n\n<li><a href=\"https:\/\/landresources.montana.edu\/soilfertility\/html\/PR_SoilTestKits.html\" rel=\"noopener\">Soil test kits vs. laboratory tests (2019), Montana State University<\/a>: test kits compared with the laboratory<\/li>\n\n\n\n<li><a href=\"https:\/\/ag.purdue.edu\/department\/hla\/extension\/extension-publications-library\/ext-pubs\/ho-71-w.html\" rel=\"noopener\">Daniel, Lerner &#038; Ackerson, Collecting Soil Samples for Testing (HO-71), Purdue University<\/a>: taking a soil sample and how often to test<\/li>\n\n\n\n<li><a href=\"https:\/\/soiltesting.cahnr.uconn.edu\/fertilizing-houseplants\/\" rel=\"noopener\">Pettinelli, Fertilizing Houseplants, University of Connecticut<\/a>: feeding pot plants, signs of too much fertiliser<\/li>\n\n\n\n<li><a href=\"https:\/\/www.nrcs.usda.gov\/sites\/default\/files\/2022-10\/Soil%20Electrical%20Conductivity.pdf\" rel=\"noopener\">Soil Electrical Conductivity, USDA NRCS<\/a>: what an EC meter does and does not measure<\/li>\n<\/ul>\n\n\n\n<p class=\"pct-kb-updated wp-block-paragraph\">Last updated: 10 November 2026<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Knowledge base \u00b7 NPK soil test NPK soil test: which nutrients is your soil missing? An NPK soil test tells you whether there is enough nitrogen, phosphorus and potassium in the soil. Here you\u2019ll learn to spot deficiencies on the leaves, which test method to choose and how to take a good soil sample. Updated [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_jetpack_hide_featured_image":false,"_jetpack_featured_image_duplicate_dismissed":0,"footnotes":""},"class_list":["post-4007","page","type-page","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v28.4 (Yoast SEO v28.8) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>NPK soil test: spot deficiencies and test your soil - Plant Care Tools<\/title>\n<meta name=\"description\" content=\"NPK soil test: enough nitrogen, phosphorus and potassium? 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