{"id":3174,"date":"2026-09-21T20:10:16","date_gmt":"2026-09-21T20:10:16","guid":{"rendered":"https:\/\/www.tomat-pomidor.com\/en\/?p=3174"},"modified":"2026-09-24T08:18:15","modified_gmt":"2026-09-24T08:18:15","slug":"tomato-leaves-turning-brown","status":"publish","type":"post","link":"https:\/\/www.tomat-pomidor.com\/en\/tomato-leaves-turning-brown\/","title":{"rendered":"Tomato Seedling Leaves Edges Turning Brown &#038; Crispy: Lighting Fixes"},"content":{"rendered":"<p><script type=\"application\/ld+json\"><span data-mce-type=\"bookmark\" style=\"display: inline-block; width: 0px; overflow: hidden; line-height: 0;\" class=\"mce_SELRES_start\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [{\n    \"@type\": \"Question\",\n    \"name\": \"Why are my tomato seedling leaves turning brown and crispy?\",\n    \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"While often mistaken for Potassium deficiency or bad soil, pale, thin, and crispy parchment-like leaves on tomato seedlings are a classic symptom of severe light deficiency. The plant sacrifices lower leaves to push energy to the top.\"\n    }\n  }, {\n    \"@type\": \"Question\",\n    \"name\": \"How long should grow lights be on for tomato seedlings?\",\n    \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"To recover light-starved seedlings, run grow lights 24\/7 for about 5 days. Afterwards, maintain a schedule of 18 hours on and 6 hours off until planting outdoors.\"\n    }\n  }]\n}\n<\/script><\/p>\n<div class=\"tldr-box\" style=\"background: #f4f9f4; padding: 20px; border-left: 5px solid #4CAF50; margin-bottom: 30px; border-radius: 4px;\">\n<h3>\ud83d\udccc Quick Summary (TL;DR): Brown, Crispy Seedling Leaves<\/h3>\n<ul>\n<li>\ud83c\udf42 <strong>The Problem:<\/strong> The leaves on your tomato seedlings are turning thin, brown, and crispy (like parchment paper) before eventually falling off.<\/li>\n<li>\ud83d\udd0e <strong>Common Misdiagnoses:<\/strong> Growers often mistake this symptom for bad potting soil, overwatering, or a Potassium (K) deficiency (since the plant pulls mobile nutrients from the lower leaves to save the growing tip).<\/li>\n<li>\ud83d\udca1 <strong>The Real Culprit:<\/strong> According to veteran growers, this specific pale, crispy die-off is a classic symptom of <strong>severe light deficiency<\/strong>.<\/li>\n<li>\ud83d\udee1\ufe0f <strong>The Fix:<\/strong> Run your grow lights 24\/7 for about 5 days to help the plant recover. After that, keep the supplemental lights running for at least 18 hours a day until it is time to plant them outside. If they are on a windowsill, push them as close to the glass as possible.<\/li>\n<\/ul>\n<\/div>\n<div class=\"add-review-cta\" style=\"margin: 20px 0; padding: 15px; background: #f9f9f9; border-left: 4px solid #4CAF50; border-radius: 4px;\"><strong>\ud83c\udf45 Seedlings looking sad?<\/strong> <a href=\"#wpdcom\">Click here to ask for a diagnosis below!<\/a><\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">I<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Iskorka (Irina) <span class=\"author-stats\">\u2b50 Pro Grower (8,959 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd Krasnoyarsk Region, Russia (USDA Zone 2b)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p>Good evening Lyudmila and everyone!<\/p>\n<p>Can you help me figure out what&#8217;s wrong with these tomatoes? My niece sent me these photos and wrote:<br \/>\n<em>&#8220;I left some on a shelving unit (with standard LED grow lights), and put the others on the windowsill. But in both spots, the leaves on most of them are drying out, turning thin and brown like parchment paper, and falling off. The soil is commercial bagged mix (Terravita). I water them with plain water when needed, haven&#8217;t added any fertilizer.&#8221;<\/em><\/p>\n<p><a href=\"https:\/\/www.tomat-pomidor.com\/uploads\/monthly_2021_03\/image.png.660d8d045f02128c191940432d60d27c.png\"><img loading=\"lazy\" decoding=\"async\" style=\"max-width: 100%; height: auto; margin-right: 5px;\" src=\"https:\/\/www.tomat-pomidor.com\/uploads\/monthly_2021_03\/image.thumb.png.91e018dcd0531237fc545031ce8a9fa7.png\" alt=\"Tomato seedling with brown crispy leaves\" width=\"300\" height=\"225\" \/><\/a><\/p>\n<p><a href=\"https:\/\/www.tomat-pomidor.com\/uploads\/monthly_2021_03\/image.png.b5c48258a64f1dec44cc0199fcf58483.png\"><img loading=\"lazy\" decoding=\"async\" style=\"max-width: 100%; height: auto;\" src=\"https:\/\/www.tomat-pomidor.com\/uploads\/monthly_2021_03\/image.thumb.png.2fb334f685a4612fb32ab06a2aeea74b.png\" alt=\"Parchment like dried tomato leaves falling off\" width=\"300\" height=\"225\" \/><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">G<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">galka68 <span class=\"author-stats\">\u2b50 Pro Grower (24,651 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd Belarus (USDA Zone 5)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p>I had this exact same thing happen with that specific potting soil (Terravita) last year. There was absolutely no root development in it. Unfortunately, that brand has been very hit-or-miss lately. Tell her to try transplanting two of them into a completely different brand of soil, just to rule out a bad batch of potting mix.<\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">E<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Evgenia 03 (Evgeniya) <span class=\"author-stats\">\u2b50 Pro Grower (1,586 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd Ulan-Ude, Buryatia, Russia (USDA Zone 3)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p>My opinion\u2014she is overwatering them. She needs to gently aerate\/scratch the topsoil and let them dry out.<\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">A<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Aleksan9ra (Lyudmila) <span class=\"author-stats\">\u2b50 Pro Grower (15,056 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd Moscow Region (USDA Zone 4)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p>Irina, there&#8217;s not enough info here. Are they already in 16 oz (0.5L) cups? If so, it means she potted them up recently. Did they look sick before she potted them up, and if so, how long ago did this start?<\/p>\n<p>My first impression is that the seedlings actually look decent structurally\u2014the stems are thick, they aren&#8217;t leggy, and they have breathing room. BUT they are extremely pale. That means either they aren&#8217;t getting enough light, they lack nutrients, or the roots aren&#8217;t absorbing nutrients. And the leaves literally look burned.<\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">V<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Valtwelve (Valeriy) <span class=\"author-stats\">\u2b50 Pro Grower (1,847 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd Volga Region, Russia (USDA Zone 4)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p>The lower leaves are yellowing. Lower leaves turn yellow because of a lack of mobile macronutrients\u2014the plant sacrifices the bottom leaves to move those nutrients up to the top, because the plant&#8217;s main priority is keeping the growing tip alive.<\/p>\n<p>It doesn&#8217;t look like Nitrogen deficiency. Not Phosphorus either. Not Magnesium or Manganese. That leaves Potassium. It looks like Potassium deficiency. There&#8217;s also Zinc deficiency, but if it were that, the new young leaves at the top would be tiny and deformed too. So if it&#8217;s not an actual disease\u2014I would try applying Potassium Sulfate both as a foliar spray and a root drench.<\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\" style=\"border: 2px solid #FFC107; background-color: #fffaec;\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\" style=\"background-color: #ffc107; color: #000;\">A<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Astero <span class=\"author-stats\">\u2b50 Expert Diagnosis (24,465 posts)<\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p><strong>This is a severe lack of light.<\/strong><\/p>\n<p>For the ones on the shelving unit, she needs to turn the grow lights on 24\/7 for about five days. After that, keep the supplemental lights running for at least 18 hours a day until it&#8217;s time to plant them outside.<\/p>\n<p>The ones on the windowsill need supplemental grow lights too. As a last resort, she can line them up in a single row pressing them as close to the window glass as possible. That will help, assuming you get some actual sunny days.<\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">S<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Svetikk <span class=\"author-stats\">\u2b50 Pro Grower (29,360 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd South Moscow Region, Russia (USDA Zone 4)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<blockquote><p><strong>Iskorka:<\/strong> &#8220;I left some on a shelving unit (with standard LED grow lights), and put the others on the windowsill.&#8221;<\/p><\/blockquote>\n<p>Which direction do those windows face? Could you get her to take a wide-angle photo showing exactly how they are arranged on the shelf and the windowsill? And what exactly does she mean by &#8220;standard LEDs&#8221;? I agree, the main cause here looks like a severe lack of light combined with sowing them too early.<\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\" style=\"border: 2px solid #FFC107; background-color: #fffaec;\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\" style=\"background-color: #ffc107; color: #000;\">A<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Astero <span class=\"author-stats\">\u2b50 Expert Diagnosis (24,465 posts)<\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<blockquote><p><strong>Valtwelve:<\/strong> So if it&#8217;s not an actual disease\u2014I would try applying Potassium Sulfate both as a foliar spray and a root drench.<\/p><\/blockquote>\n<p>Never take diseases or nutrient deficiencies that happen to mature plants grown in the garden\/greenhouse and try to apply them to indoor seedlings. Seedlings do not get diseases, other than Damping Off (and you really have to mess up your watering to get that).<\/p>\n<p>Literally every other problem with indoor seedlings is a physiological disorder caused by the grower messing up the environment (light, watering, temp).<\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">I<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Iskorka (Irina) <span class=\"author-stats\">\u2b50 Pro Grower (8,959 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd Krasnoyarsk Region, Russia (USDA Zone 2b)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p>They are cold white 15W LED strip lights. We saw a guy on social media recommending these specific strips for seedlings.<\/p>\n<p>Thank you everyone so much for the advice! I passed it all on to her!<\/p>\n<p><a href=\"https:\/\/www.tomat-pomidor.com\/uploads\/monthly_2021_03\/image.png.ce385ca1cafdbd9cf2fefececa1b2bce.png\"><img loading=\"lazy\" decoding=\"async\" style=\"max-width: 100%; height: auto;\" src=\"https:\/\/www.tomat-pomidor.com\/uploads\/monthly_2021_03\/image.thumb.png.77936777c3c78a79b6f5c74727342d7c.png\" alt=\"Inadequate 15W LED grow lights over tomato seedlings\" width=\"225\" height=\"300\" \/><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">A<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Aleksan9ra (Lyudmila) <span class=\"author-stats\">\u2b50 Pro Grower (15,056 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd Moscow Region (USDA Zone 4)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p>Irina, you can clearly see in that new photo that the seedlings are absolutely miserable under those lights, they look depressing. Aside from fixing the lighting, she also needs to re-evaluate her watering and feeding schedule.<\/p>\n<\/div>\n<\/div>\n<div class=\"forum-post\">\n<div class=\"author-header\">\n<div class=\"forum-avatar\">S<\/div>\n<div class=\"author-meta\">\n<div class=\"author-name\">Svetikk <span class=\"author-stats\">\u2b50 Pro Grower (29,360 posts)<\/span><\/div>\n<div class=\"author-geo\">\ud83d\udccd South Moscow Region, Russia (USDA Zone 4)<\/div>\n<\/div>\n<\/div>\n<div class=\"post-content\">\n<p>Those lights are clearly not enough. If it were my setup, I would replace those strips with actual full-spectrum E27 socket grow bulbs (yes, they are more expensive, but read the reviews first). And I would definitely re-sow a few of them; under proper lighting, new ones will catch up and grow much faster and healthier. Also, whenever possible, she should be carrying them to a bright window or balcony to get natural sunlight.<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\ud83d\udccc Quick Summary (TL;DR): Brown, Crispy Seedling Leaves \ud83c\udf42 The Problem: The leaves on your tomato seedlings are turning thin, brown, and crispy (like parchment paper) before eventually falling off. \ud83d\udd0e Common Misdiagnoses: Growers often mistake this symptom for bad potting soil, overwatering, or a Potassium (K) deficiency (since the plant pulls mobile nutrients from &#8230; <a title=\"Tomato Seedling Leaves Edges Turning Brown &#038; Crispy: Lighting Fixes\" class=\"read-more\" href=\"https:\/\/www.tomat-pomidor.com\/en\/tomato-leaves-turning-brown\/\" aria-label=\"Read more about Tomato Seedling Leaves Edges Turning Brown &#038; Crispy: Lighting Fixes\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":3174,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[529,472],"tags":[],"class_list":["post-3174","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-growing-tomatoes","category-diseases-weeds"],"_links":{"self":[{"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/posts\/3174","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/comments?post=3174"}],"version-history":[{"count":7,"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/posts\/3174\/revisions"}],"predecessor-version":[{"id":3387,"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/posts\/3174\/revisions\/3387"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/posts\/3174"}],"wp:attachment":[{"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/media?parent=3174"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/categories?post=3174"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tomat-pomidor.com\/en\/wp-json\/wp\/v2\/tags?post=3174"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}