The condition of the foliage is an important indicator by which one can judge the health of plants. This is an organ that combines several vital functions. Photosynthesis, water and gas exchange, and accumulation of nutrients occur in the leaf blade. If the lower leaves of tomato seedlings turn yellow and fall off prematurely, this indicates a disruption in the process of chlorophyll production. Such seedlings do not have the strength to grow normally. Chlorosis (yellowing and falling leaves) is caused by a number of reasons. The quality of the future tomato harvest depends on how quickly problems are identified and corrected.
Why leaves fall on tomato seedlings
Chlorosis is a natural process. The cotyledon leaves turn yellow after the plant has used up the initial supply of nutrients contained in the seed. It is necessary for the formation of the root system and germination. Subsequently, the seedlings grow and develop independently.
After the seven segments have fallen off, the next phase of development of tomato seedlings begins . True leaves are formed. Their number gradually increases as they grow, but if growing conditions are violated, they begin to turn yellow and fall off.
The following reasons are known why cotyledon leaves of tomato seedlings fall prematurely:
- excess moisture;
- lack of light;
- nutritional deficiencies;
- poor quality soil;
- non-compliance with temperature conditions;
- presence of diseases.
After transplanting grown tomato seedlings to a permanent place, the leaf mass may also turn yellow, after which it will begin to fall off. The reason for this is stress from changing living conditions. To prevent this, it is imperative to harden off the seedlings before transferring them to open ground.
Tomato leaves turn yellow in open ground
Seedlings in an open area are much more exposed to any external influences. These are winds, rains, scorching sun, insects and pests - which means it is important to quickly determine the source of the problem.
— During drought and heat, the leaves of tomatoes dry out from lack of moisture, so increase the frequency of watering;
— If it’s cold outside and it’s been raining for a long time, there’s probably too much moisture, so come up with a shelter;
— Tomatoes often turn yellow due to unexpected frosts, because this is their natural reaction to hypothermia;
— The leaves will turn yellow if the rhizome is accidentally damaged during excavation work. The plant then focuses on recovery and sends fewer nutrients to the above-ground part. This is a normal process, so just watch;
— When there is not enough nitrogen and potassium in the soil, the leaves grow weaker, become smaller, become deformed and turn yellow. This is a sure signal to carry out unscheduled feeding;
— Tomatoes get sick, like any other plants. Late blight or mosaic stains are usually irregular, haphazard and chaotic. They spread rapidly, change color and texture, and can swell or dry out. Not all diseases can be treated, and damaged bushes must be isolated immediately without waiting for them to spread.
Photo: proroslo.ru
Why do pepper leaves turn yellow and dry?
Excess moisture
Stagnation of moisture in the soil negatively affects the health of tomatoes. The main reason for the falling of the lower leaves due to excessive watering is acidification of the soil. It can be identified by a whitish coating on the soil surface. If waterlogging continues for a long time, it can lead to the development of fungal infections.
When water stagnates, the root system experiences oxygen starvation, as a result of which the seedlings begin to turn yellow and shed their leaves. Urgent resuscitation will help to avoid the death of plants.
There are other possible violations of watering rules that should not be allowed when growing tomatoes:
- Watering with cold water results in stress for the root system and a decrease in the level of nutrient absorption.
- It is not recommended to use unsettled, chlorinated water. Such moisture may contain impurities that are poisonous to tomatoes.
- Irregular watering. Overdrying the soil is no less dangerous for seedlings than overmoistening it.
Ideal watering of tomatoes should provide an abundant supply of water to the roots as the soil dries out with regular loosening. This is necessary so that during the formation of the ovaries the flower stalks do not begin to turn yellow and fall off en masse.
Equally dangerous for tomatoes is too dry air in homes with central heating. To soften the atmosphere, place a damp cloth on hot radiators, which is changed regularly or containers with water are placed.
Causes of yellowing leaves: improper care
Damage to roots when transplanting seedlings into a greenhouse
It is possible to destroy some of the young seedlings if the seedlings are not carefully planted in the garden. During transplantation, due to improper actions of the gardener, fragile roots are often damaged. True, if a small part of the roots was damaged, then they will soon grow back and the seedling will resume development, but the yellowed leaves, alas, will not return their green richness.
Please note: the best way to transplant seedlings is considered to be the transshipment method, that is, preserving the earthen clod on the rhizome.
The roots can be damaged by rough loosening. This can even happen to mature plants.
Spraying with Kornevin or fertilizing with mineral compounds will help restore the health of damaged bushes.
Improper watering of tomatoes
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Tomatoes tolerate drought more easily than heavy moisture. Despite the fact that their root system is highly developed and most of it is located deep in the soil, the main part is still located near the surface, and therefore frequent and abundant soil moisture has a detrimental effect on their healthy development. In addition, constant stagnation of water can provoke the development of diseases.
Long breaks in watering also have a negative effect on tomatoes. An imbalance - severe drying out of the soil, and then waterlogging - causes stress to the plant. It slows down its development, which immediately affects its appearance - the leaves become pale, faded, and turn yellow along the entire base of the bush.
Attention: you need to water tomatoes twice a week, spending up to three liters of water per bush.
In addition, yellowing of foliage (curling, wilting, darkening, dying) is also possible due to improper watering techniques.
Remember: you should water tomatoes only at the root, without touching the green part of the bush. Wet leaves quickly become sick and turn yellow.
Mulching the area under the tomatoes with compost or straw will help retain moisture in the soil for a long time. However, it should be borne in mind that in too hot summers, mulch can cause overheating of the roots, as it reliably retains heat underneath.
Violation of the greenhouse microclimate
In protected soil, plant life depends entirely on the efforts of the gardener. If you do not control the level of humidity and temperature inside the greenhouse, then you can forget about a good harvest, or even not expect it at all. Often, due to accumulating condensate and extreme heat, plants are suppressed and development processes are stopped. Plants become weak, defenseless against insect pests and diseases. Sudden changes in temperature, for example, lead to a stop in growth and shedding of ovaries. When overheated, the leaves on seedlings turn yellow, and overcooling leads to wilting and loss of elasticity. The root system works at half capacity and does not provide the foliage with everything it needs.
Remember: the maximum permissible temperature in a greenhouse is +32 degrees; minimum – +16 degrees.
You can control the level of humidity and temperature using ventilation. If the weather is hot and sunny outside, the doors and windows of the greenhouse should be kept open.
Tip: to reduce exposure to ultraviolet radiation, greenhouse glass can be covered with lime. And buckets of water placed along the beds will help maintain the optimal temperature throughout the day: during the day, cold water will take away heat, and at night it will release it.
Failure to comply with planting deadlines
When purchasing a tomato, an attentive gardener will notice on the seed package information about at what age the seedlings should be planted in the garden. Usually it is 55-65 days (depending on the ripening time of a particular variety). However, many people neglect this information and plant tomatoes not on time, but whenever possible. However, failure to comply with the planting time affects the further development of tomato seedlings. The thing is that plants have their own life cycles, the maintenance of which leads to a good harvest. For example, if you plant overgrown seedlings, then their root system, which is already thoroughly formed, will be partially damaged due to the fact that there was not enough space in the seedling container for normal development. Moreover, overripe seedlings are already beginning to bloom, and if they are planted in the garden at this moment, the flowers that have formed will stop developing and fall off, which means that part of the harvest will be lost. Such seedlings will take root poorly or stop growing altogether. Planting underdeveloped tomato bushes also leads to their disease - the leaves will begin to wither, turn yellow and curl.
Lack of light
Often the reason why the lower leaves of tomatoes wither and fall off is poor lighting. Normal growth and development of tomatoes is impossible if they lack sunlight.
To obtain viable seedlings, the gardener must be able to competently regulate the amount of ultraviolet radiation reaching them. Light deficiency develops if sowing work is carried out during a period of low solar activity (in February or March), with a large number of cloudy days. The leaves of seedlings planted too densely also begin to dry out, turn yellow and fall off, as they shade each other.
Signs of sunlight deficiency:
- stretching the stems, bending them towards the light source;
- darkening of the green mass, in which active production of chlorophyll begins;
- a large number of fallen leaves.
For proper development, daylight hours for tomatoes should be at least 10 hours. Containers with seedlings are placed on the windowsill on the south-eastern side of the house, and, if there is a lack of natural light, special daylight phytolamps are used.
Too much sun is also dangerous. An excess of ultraviolet radiation can cause severe burns on seedlings, causing them to wither.
How to help tomatoes
The first thing to do is isolate the damaged parts of the plants and burn them.
Tomato disease!
Top rot of tomatoes in a greenhouse
The second thing is to treat the plants with chemicals in case of severe damage in accordance with the instructions.
When the disease has not yet spread, non-traditional “folk” remedies are used.
Third, remember that prevention is better than cure, and therefore take preventive measures:
- maintain a favorable microclimate in the greenhouse (temperature, humidity);
- Carry out proper, systematic care (watering, fertilizing tomatoes).
Prevention will strengthen the immunity of tomatoes, and accordingly, minimize the risk of disease.
Nutrient deficiency
The most important condition for obtaining healthy and strong seedlings is a sufficient amount of microelements in the soil. Seedlings throughout their development must receive a balanced set of nutrients. It is applied during the main tillage of the soil under the beds, as well as during certain phases of plant development.
Acute lack of nutrients is eliminated by spraying with preparations for foliar feeding. In this case, the effect occurs very quickly, since absorption occurs through stomata or tubules located on the surface of the leaf blades.
The main complex of essential microelements for tomatoes includes nitrogen, potassium, phosphorus, calcium, magnesium, sulfur, and iron.
The deficiency of each nutrient is characterized by certain symptoms, knowing which, you can regulate their intake:
- Nitrogen deficiency is noticeable in the early stages of growth. Without this microelement, normal development and fruiting of tomatoes is impossible. The main symptoms are curling of the lower leaves and a significant lag in plant development.
- Phosphorus takes part in the formation of the root system. Its deficiency reduces resistance to disease. Deficiency manifests itself in the curling of leaves and the appearance of purple veins on the underside of the leaves.
- Potassium forms immunity, affects the taste of future fruits, and increases their keeping quality. Symptoms of deficiency include shredding of leaf blades, curling and drying out at the edges, and the appearance of rust.
- Calcium is involved in growth processes and the formation of the root system. The trace element stimulates the development of roots. Symptoms of deficiency are the appearance of characteristic opalines and light spots on the leaves.
- Sulfur is involved in oxygen metabolism. With its deficiency, plant leaves wither and become brittle.
- Magnesium takes part in the process of fruit formation. The deficiency manifests itself as follows: the lower leaves bend in the shape of a “house”, dry out at the edges, and begin to fall off.
- Iron deficiency is especially noticeable in the early phase of development and at the flowering stage. A characteristic yellow border forms on the foliage of the seedlings.
Damage to the root system
Damage to the roots can also cause tomato leaves in a greenhouse to turn yellow. Most often this happens when transplanting seedlings into a greenhouse. Therefore, it is important not to overexpose the planting material on the windowsill.
To restore the culture in this case, the plant must be properly cared for. With proper agrotechnical care, the crop will quickly recover.
Damage to the root system also occurs during hilling. The main root goes deep into the soil, and the lateral roots are on the surface and are subject to mechanical stress. This problem is solved by careful hilling, which will help restore the normal state of the tomatoes.
Poor quality soil
If tomato seedlings begin to turn yellow at the cotyledon stage, you need to pay attention to the quality of the soil. The soil must be thoroughly disinfected and have the correct composition.
Heavy peat soil is characterized by high adhesiveness, so it is not suitable for growing tomatoes. Dense areas that do not contain air provoke oxygen starvation of the root system. This interferes with the normal nutrition of the seedlings. As a result, the foliage begins to turn yellow and fall off.
Too acidic soil forms nitrogen, potassium, and phosphorus salts that are not absorbed by plants. An excess of inorganic additives and hard water during irrigation are the reasons for its salinity.
The mixture with the following composition is most suitable for propagating tomato seedlings:
- turf – 1 part;
- river sand – 1 part;
- peat - 1 part;
- perlite - 1 part;
- coconut substrate - 1 part;
- ash – 0.5 parts.
To strengthen the protective forces, it is recommended to water the plantings with melt or rain water.
Gardening tips
To avoid the appearance of yellowness on the leaves, experienced gardeners advise following the following rules:
- compliance with planting deadlines. Overgrown seedlings already have problems with the root system, which begins to die. Such a process can rarely be reversed;
- carrying out proper watering. For tomatoes, root watering is suitable; water should not fall on the foliage and stem part;
- To ensure that tomatoes do not suffer from a lack of useful microelements, it is necessary to observe the period for applying fertilizers;
- Timely treatment with manganese and copper-containing preparations serves as an excellent prevention of various diseases;
- Any work with tomatoes must be done carefully; the plants must not be damaged by careless human actions. It is recommended to work with sharp and clean tools.
Failure to comply with temperature conditions
Tomatoes are a heat-loving crop. To ensure that the ovaries do not begin to turn yellow and fall off, it is important to observe the temperature regime when caring for seedlings. It consists of regulating temperature at different stages of growth:
- It is not recommended to sow seeds earlier than mid-March, when daylight hours are still too short and the seedlings are too cold on the windowsill.
- The optimal temperature for germinating seed material is 23-25°C.
- After germination, it is important to prevent the sprouts from stretching. The optimal air temperature during this period is 16-18°C.
- 10 days after the emergence of seedlings, it is recommended to set a new temperature regime: increase daytime values to 20-23°C, and set nighttime values at 17-19°C.
A decrease in temperature values, overheating, as well as a sharp change in temperature leads to the cessation of development of the root system. As a result, the stems stretch unnaturally, and the lower leaves dry out and begin to fall off.
Damage to tomatoes by insect pests
Insect pests are another reason why tomato leaves may dry out.
To determine the type of pest, you need to carefully examine the underside of the leaf blade. The most common causes of this problem are aphids, whiteflies, and spider mites.
Small black individuals localized in the folds of the plant are aphids.
It is very dangerous because it feeds not only on plant sap. The insect injects a substance into the plant itself, which leads to a change and disruption of the shape of the tomatoes.
Photo of aphids on tomatoes
Whiteflies live in entire colonies and are represented by small white insects. The larvae eat almost all the green mass. Their waste products are dangerous for tomatoes, as they infect them with fungus.
Photo of whiteflies on tomatoes
Spider mites are located on the bottom of the leaves
and is capable of infecting all tomatoes in just a few weeks.
Photo of spider mites on tomatoes
To combat pests, specialized insecticides, digging, soil replacement, and mulching are used.
Presence of diseases and pests
Quite often, the green crown begins to wither, turn yellow and fall off during illness or when attacked by pests.
Tomato seedlings usually have strong immunity, but in the presence of accompanying unfavorable conditions (dense plantings, too much watering), fungal infections such as black leg, fusarium, and various rots can develop on them. To avoid the risk of their spread, seed material must be treated before planting, and planting containers must be thoroughly disinfected.
Blackleg causes thinning of the stems with the formation of constrictions at the base of the stem. For protection, you can treat the soil with a solution of potassium permanganate. If the infection spreads massively, the affected seedlings will have to be destroyed.
The initial symptom of fusarium is yellowed lower leaves that begin to fall off. As the disease progresses, it completely covers the bush.
The stem cut turns brown. The main therapeutic methods are as follows: reducing the amount of watering, using fungicides (Fitosporin solution is effective).
Pests such as spider mites, aphids, and greenhouse whiteflies are dangerous for tomato seedlings. The main symptoms of infection are leaf curling. Then it begins to turn yellow and fall off.
Insects are gotten rid of by treating the plantings with tobacco or garlic infusion, Actellik or Fitoverm insecticides.
Incorrect feeding
Due to a lack or excess of nutrients, the leaves of tomatoes in the greenhouse also turn yellow. A lack of essential microelements causes tomatoes in the greenhouse to turn yellow. What to do in this case?
Here it is also necessary to correctly understand which microelements are missing in this case. Nitrogen deficiency causes the stems to become thin and the leaves to become small and yellow. This problem is easy to solve.
It is enough to apply nitrogen fertilizers in the form of mineral preparations, which can be bought in specialized stores. It will also be good to use mullein infusion. To do this, you need to let the mixture of manure and water sit for a week, and then the resulting mass is diluted 1/10 with water.
Phosphorus deficiency manifests itself as yellowed foliage at the top of the main stem. This problem can be solved by feeding the plant with superphosphate, which is applied in the proportions of 8 liters of water to 100 grams of the substance.
With a deficiency of manganese, young leaves first turn pale and then turn yellow, and a little later adult leaves. To eliminate the lack of manganese, add a solution of mullein (one part of mullein is diluted in 20 liters of water) or a solution of potassium permanganate (1 teaspoon of manganese is dissolved in 6 liters of water) under the roots of the plant.
Preventive measures against yellowing of tomato foliage
To get rid of yellowing leaves, be sure to carry out prevention. It is necessary to start with seed disinfection
before sowing. During growth, observe the thermal regime and proper care of tomatoes.
But if yellow spots have already begun to appear on the plants, first of all normalize the watering system
. Spray tomatoes with fertilizers containing microelements. Follow the proportions indicated on the packaging. Spray with fertilizer for several days until new leaves grow to replace the old, yellowed leaves.
It is unlikely that you will be able to restore completely yellowed leaves; spend more time restoring the tomatoes. This way you will save the harvest.
Fertilizer shortage
It happens that tomato leaves begin to turn yellow if there is an insufficient amount of nutrients in the soil. This often happens in greenhouses over a large area or in open areas, in other words, where it is more difficult to control the quality of the soil.
Nitrogen
When a plant lacks this substance, it is immediately noticeable. The main signs are yellowing and falling off of dried tops. If this problem is not corrected urgently, the bushes begin to stretch out and the shoots become pale.
Important! It is necessary to apply fertilizers with nitrogen when transplanting tomatoes to a permanent place and when the fruits begin to set.
The benefit of nitrogenous fertilizers is the growth of green mass. Urea can be used for feeding. To do this, you need to dissolve 40 g of the substance in a bucket of water and spray the plantings.
The main thing is not to forget to dose fertilizers correctly. If there is too much nitrogen, the tomato tops will grow vigorously. The crop needs to be fed only until its condition improves.
Potassium
With a lack of this substance, the leaves turn yellow and dry, and the young shoots curl into a boat. Small spots appear along the edges, which subsequently merge with each other, causing the leaves to dry out.
Plants are fertilized with potassium during the growing season, at any stage. But you should pay attention when the fruits begin to ripen.
Advice! Fertilizers containing potassium must be chosen without chlorine.
You can choose potassium sulfate for such feeding. Thanks to it, the amount of vitamins and sugars in vegetables will increase, which allows the plant to acquire resistance to diseases.
To feed the tomatoes, take 40g of potassium sulfate, which must be dissolved in a bucket of water. Water the crop at the root or spray it on the leaf.
Magnesium
If its quantity is insufficient, the leaves first turn yellow along the veins and then curl.
Magnesium sulfate will help restore the normal level of this substance. For watering at the root, take 40 g per 10 liters of water, and for spraying - 20 g per the same amount of water.
The beneficial properties of magnesium include helping in the absorption of other substances such as nitrogen, phosphorus and calcium. This has a positive effect on the yield, the taste of the fruit, and the speed of development.
Sulfur
By the appearance of red veins on the leaves, which acquire a light green tint and subsequently turn yellow, a sulfur deficiency can be diagnosed. If this deficiency is not corrected, the stems become weak and brittle.
Ammoniated sulfate is well suited to restore sulfur deficiency. It can simply be dissolved in water for watering tomatoes. This will provide vegetables with sufficient amounts of sulfur and potassium.
Iron
Chlorosis occurs due to iron deficiency. In such cases, yellow leaves appear, but the veins remain green. With a long-term deficiency, the color at the top of the bush loses brightness and saturation, and the bush stops developing.
To compensate for iron deficiency, use a solution of iron sulfate. To prepare, take 5g of water per bucket and spray the tomato bushes . To consolidate the result, you should repeat the procedure after 7 days.
Methods to combat the problem
If only a few lower leaves turn yellow, the problem is minor, and often it is not a problem at all: after all, during the ripening of fruits this is a completely natural process. Moreover, the lower leaves are specially cut off at this time so that they do not distract food. If they turn yellow ahead of time, they should also be torn off: the development of the bush will hardly stop as a result, and new leaves will grow, provided that all other growing conditions are met.
It is important not to damage the stem when cutting off the leaves, so it is better to cut them with sharp scissors.
However, with massive yellowing of leaves, it is no longer possible to talk about the normality and naturalness of this process; it is necessary to understand the cause. In most cases, you can correct the situation:
- an irrigation regime should be established (watering is carried out in the morning or evening, avoiding waterlogging, using water heated in the sun);
- feed the plants (maybe this should be done outside the plan), taking into account that the most effective fast-acting foliar feedings are;
- if fusarium is clearly detected, you can try to save at least those bushes that are slightly diseased: effective drugs are Previkur and Trichodermin, they are used according to the instructions on the package.
In severe cases, when the entire bush has turned yellow, it is no longer possible to hope for a normal harvest, but it is worth trying to minimize losses: after all, the necessary measures are not so complicated.
