Brown irregular spots on the sides of the fruits that appear along with leaf damage may indicate late blight<\/strong>. The surface is usually firm, later changes, and the damage can spread quickly.<\/p>\n\n\n\n A light, yellowish, or whitish spot on the side facing the sun is often sunscald<\/strong>. The damaged tissue may dry out over time, darken, and then be colonized by other microorganisms.<\/p>\n\n\n\n Blossom end rot occurs when young tissue does not receive enough calcium at the critical time. The soil may contain enough calcium, but the plant cannot take it up and transport it evenly.<\/p>\n\n\n\n The most common trigger is fluctuations in soil moisture. After a period of drought comes heavy watering or rain, the roots work unevenly, and the rapidly growing fruit remains insufficiently supplied.<\/p>\n\n\n\n The problem is worsened by damaged roots, saline soil, excess nitrogen, and extreme heat. Therefore, simply adding calcium may not bring improvement.<\/p>\n\n\n\n Tomatoes should not wilt one day and stand in waterlogged soil the next. Such alternation stresses the roots, promotes cracking, and disrupts the even supply of nutrients.<\/p>\n\n\n\n Water slowly and thoroughly to the roots. Adjust the next dose to the soil type, weather, and plant size, not a fixed daily schedule.<\/p>\n\n\n\n The surface may be dry, even though the soil deeper down is still moist. Therefore, check it a few centimeters below the surface before watering.<\/p>\n\n\n\n A thin layer of straw, dried grass, or other suitable organic material slows evaporation. The soil remains more evenly moist and does not overheat as much.<\/p>\n\n\n\n Mulch also cushions the impact of rain, so the soil does not splash onto the lower leaves. This reduces the risk of transmitting some disease agents.<\/p>\n\n\n\n Do not place the material right up to the stem. A small free circle around the neck improves air flow and limits rot.<\/p>\n\n\n\n Foliar and fruit sprays with calcium are often recommended as a quick rescue, but their effect on already formed necrosis is limited. The damaged spot will not turn back into healthy tissue.<\/p>\n\n\n\n Calcium is transported in the plant mainly by the water stream from the roots. The most important thing is therefore to restore even moisture and protect the root system.<\/p>\n\n\n\n Add calcium fertilizer only when the soil or growing substrate really needs calcium. Excess fertilization can increase salt content and worsen the problem.<\/p>\n\n\n\n Necrosis does not spread from one fruit to another. You can remove severely damaged tomatoes so the plant directs energy to healthy fruits.<\/p>\n\n\n\n A smaller dry spot can be cut off after harvest if the rest of the fruit is firm, without mold and unpleasant odor. However, consume the fruit quickly.<\/p>\n\n\n\n If the spot is soft, wet, smells bad, or mold is forming on it, throw the tomato away. Secondary rot is already a different problem than the physiological disorder itself.<\/p>\n\n\n\n With late blight, watery, later brown irregular spots appear on the leaves. In humid weather, a light coating can be observed on the underside at the edge of the damage.<\/p>\n\n\n\n Dark stripes form on the stems, and the fruits get brown firm spots. The disease can spread very quickly in cooler humid weather.<\/p>\n\n\n\n Therefore, check the plants regularly, especially after rains and with prolonged leaf wetting. The sooner you detect the problem, the larger part of the stand you can protect.<\/p>\n\n\n\n Home infusions may have limited preventive or hygienic significance, but with confirmed late blight you cannot rely on them as a reliable treatment.<\/p>\n\n\n\n Remove affected leaves and fruits with clean tools and do not place them among healthy growth. In case of heavy occurrence, follow approved preparations and their labels.<\/p>\n\n\n\n Spraying is most important preventively or at the very beginning of infection. Severely damaged tissue will not revive.<\/p>\n\n\n\n Do not remove leaves during rain or when they are wet with dew. Droplets and hands can transmit infection to other parts of the stand.<\/p>\n\n\n\n Clean and disinfect scissors between plants in a suitable way. Do not leave cut material lying under the tomatoes.<\/p>\n\n\n\n After work, wash your hands and do not unnecessarily touch healthy leaves. Simple hygiene often limits the spread more than repeated random sprays.<\/p>\n\n\n\n Sunscald forms especially on fruits that suddenly remain without leaf cover. Initially, it is a pale, yellowish, or whitish spot on the most illuminated side.<\/p>\n\n\n\n The damaged spot is usually dry and papery. Later it may darken or become an entry point for rot.<\/p>\n\n\n\n The greatest risk arises after sudden defoliation during hot periods. A fruit that previously grew in the shade does not have time to adapt to strong radiation.<\/p>\n\n\n\n Healthy leaves are not an unnecessary burden. They produce sugars, cool the plant, and protect tomatoes from direct sunlight.<\/p>\n\n\n\n Remove especially diseased, yellow, and lower leaves touching the soil. For staked varieties, pinch side shoots gradually and according to the training method.<\/p>\n\n\n\n During heatwaves, leave enough leaf area above ripening fruits. In extreme radiation, a light shading net helps.<\/p>\n\n\n\n With green collar, the area near the stem remains green, yellowish, or hard, while the rest of the fruit ripens. It is a disorder of even coloring.<\/p>\n\n\n\n It is promoted by the genetics of the variety, high temperatures, strong sun, and unbalanced nutrition. Potassium deficiency may be one factor, but it cannot be determined from just one fruit.<\/p>\n\n\n\n Do not add boron automatically. Plants need it only in trace amounts, and excess can be toxic.<\/p>\n\n\n\n Potassium supports the plant’s water management and fruit quality. If there is too little, damaged edges of older leaves and poorer crop quality may appear.<\/p>\n\n\n\n However, many garden soils contain enough of it. Further fertilization without analysis can increase salinization of the root zone and disrupt the uptake of calcium or magnesium.<\/p>\n\n\n\n Use tomato fertilizer according to the manufacturer’s instructions. Do not combine several concentrated sources of potassium and micronutrients at once.<\/p>\n\n\n\n Mechanical damage from hail, wind, or careless tying can darken later. Bruises on fruits leaning against the structure look similar.<\/p>\n\n\n\n Small corky dots may appear after insect damage. When determining them, also check the underside of leaves, stems, and young shoots.<\/p>\n\n\n\n If the spot does not enlarge and the surrounding tissue remains firm, monitor the fruit for a few days. Rapid spread, oozing, and odor are more serious signals.<\/p>\n\n\n\n When a problem appears, many growers add nitrogen, calcium, potassium, and micronutrients at once. Such a cocktail increases salt concentration and burdens already weakened roots.<\/p>\n\n\n\n First adjust watering and check water drainage. Only then address nutrition according to previous fertilization, leaf condition, and ideally soil analysis.<\/p>\n\n\n\n Use nitrogen fertilizers sparingly during strong fruit growth. Lush foliage retains moisture, but radical defoliation increases the risk of sunscald.<\/p>\n\n\n\n Substrate in a pot overheats and dries out much faster than soil in a bed. Moisture fluctuations are therefore a common cause of necrosis on balcony tomatoes.<\/p>\n\n\n\n The container must have sufficient volume and drainage holes. A small pot restricts roots and requires very precise watering.<\/p>\n\n\n\n During heatwaves, check moisture even several times a day, but do not leave the pot standing in a permanently full saucer. Waterlogged roots take up nutrients just as poorly as dried-out ones.<\/p>\n\n\n\n First, photograph the fruit and examine the leaves, stems, and neighboring tomatoes. The location and course of the damage will help you determine whether it is a physiological disorder or infection.<\/p>\n\n\n\n Check soil moisture and watering method. For necrosis, restore even watering; for sunscald, leave leaf cover; for suspected blight, remove affected parts.<\/p>\n\n\n\n Do not add fertilizer or spray just out of fear. Incorrect intervention can mask symptoms, burn leaves, or worsen nutrient uptake.<\/p>\n\n\n\n Dark spots on tomatoes are most often not stopped by one universal bottle. For necrosis, stable moisture decides; for sunscald, leaf cover; and for blight, quick hygiene and suitable protection.<\/p>\n\n\n\n You usually cannot repair a damaged fruit, but you can save the next ones. Monitor the location of the spot, do not overdo fertilization, and provide the plants with even watering and plenty of healthy leaves.<\/p>\n","protected":false},"excerpt":{"rendered":" Dark spots on your tomatoes ruining your harvest? This common mistake may be more to blame than you think. Dark spots on tomatoes do not always mean just one disease, […]<\/p>\n","protected":false},"author":3,"featured_media":23991,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-23990","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=\/wp\/v2\/posts\/23990","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=23990"}],"version-history":[{"count":1,"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=\/wp\/v2\/posts\/23990\/revisions"}],"predecessor-version":[{"id":23993,"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=\/wp\/v2\/posts\/23990\/revisions\/23993"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=\/wp\/v2\/media\/23991"}],"wp:attachment":[{"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=23990"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=23990"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.garden-tricks.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=23990"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}The black bottom of the fruit is often not caused by a lack of calcium in the soil<\/h3>\n\n\n\n
Sudden watering is a common mistake that the fruits show later<\/h3>\n\n\n\n
Mulch stabilizes conditions at the roots<\/h3>\n\n\n\n
Calcium spray can help<\/h3>\n\n\n\n
You don’t always have to remove damaged fruits immediately<\/h3>\n\n\n\n
![\"\"](\"https:\/\/www.garden-tricks.top\/wp-content\/uploads\/2026\/07\/image.png\")
<\/figure>\n\n\n\nLate blight often starts inconspicuously on the leaves<\/h3>\n\n\n\n
Garlic, soda, or nettle are not a sure cure for blight<\/h3>\n\n\n\n
When suspecting disease, work with dry plants<\/h3>\n\n\n\n
Too much sun damages exposed fruits<\/h3>\n\n\n\n
Do not remove all leaves around the clusters<\/h3>\n\n\n\n
Green collar is not a dark spot or mold<\/h3>\n\n\n\n
Potassium matters, but the dose must not be guessed<\/h3>\n\n\n\n
Not every dark spot is an infection<\/h3>\n\n\n\n
Strong fertilization can worsen symptoms<\/h3>\n\n\n\n
Tomatoes in containers react faster<\/h3>\n\n\n\n
Quick check according to the appearance of the spot<\/h3>\n\n\n\n
\n
What to do immediately after finding a damaged fruit<\/h3>\n\n\n\n
Healthy fruits are protected by correct diagnosis<\/h3>\n\n\n\n