- the essentials in brief
- Yellow leaves from too much water
- Yellow leaves from tomato diseases
- pests
- deficiency symptoms and nutrient supply
- FAQ
Are your tomatoes turning yellow or are the leaves wilting? These symptoms are usually caused by pests or deficiency symptoms and are easy to treat.
Table of Contents
Show all- the essentials in brief
- Yellow leaves from too much water
- Yellow leaves from tomato diseases
- pests
- deficiency symptoms and nutrient supply
- FAQ
- Basically, leaves turn yellow when the pigment chlorophyll is not sufficiently formed.
- The causes are manifold. It is often due to incorrect water management.
- However, yellow leaves are also a symptom of diseases and pests.
- A lack of nutrients in the soil can also lead to leaf discoloration.
- Remove and destroy infected leaves
- Sprinkle with skimmed milk
- Protect from rain and splashing water
- Ensure sufficient air circulation (e.g. max out)
- Remove and destroy infected leaves
- Remove surface compost or mulch (239.00€).
- loosen soil
- expose fertilizer
- Close-meshed insect net outdoors
- Natural predators or beneficial insects (e.g. lacewings) in the greenhouse
- Attach yellow or glue boards nearby
- Spray soft soap solution (500 ml water with approx. 8 grams soft soap) onto the plant
- Distribute primary rock dust on the surface of the plant
- Natural predators or beneficial insects (predatory mites or hoverflies) in the greenhouse
the essentials in brief
Yellow leaves from too much water
Every hobby gardener will eventually come to the point where he has given his tomato plants too little or too much water. In most cases, the tomato forgives such small mistakes. But in the long run, incorrect watering causes lasting damage - up to the complete failure of the harvest. A sign of improper water supply in both directions is yellow leaves. The moisture in the substrate is determined with a thumb test.
If it is too dry, the leaves, which were initially yellow, become limp and brown without any action being taken, until they finally fall off. If the soil feels damp, the leaves will remain yellow. The yellowing is due to a lack of nutrients, as the roots rot due to too much water (waterlogging) or have too little water to transport nutrients. In addition to removing the yellow leaves and, if necessary, repotting potted plants, the following tools facilitate the regular and sufficient water supply of tomatoes.
Caption: Optimum water balance through indirect watering
A clay pot, a watering ring or an olla can be used to water the tomato plant without splashing water.
clay pot. The inexpensive clay pot is buried in the ground next to the tomato plant. Water is then poured in from above. The irrigation water is released to the ground through the hole in the pot.
casting ring. The tomato plant is surrounded by water, which seeps through to the roots in the right amount. At the same time, the casting ring, which costs 10 to 20 euros, offers natural protection against crawling predators such as snails.
Olla. With a capacity of 1 L to 6.5 L, an Olla covers the needs of several plants at the same time. The bucket is a bit more expensive with a price range of 30 to 50 euros, but has a long service life.
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Bio Green watering ball Hydro Max -S, terracotta, 14 x 14 x 19 cm, HM-S
28.87 EUR To the productYellow leaves from tomato diseases
Caption: Appearance of diseased leaves
Fungi and bacteria cause yellow leaves on tomatoes
If watering is regular and moderate, but the foliage still appears yellow, a disease may be the cause of the discoloration. Leaf spot infection or bacterial wilt should be considered for yellow leaves. If such a suspicion is confirmed, immediate action must be taken to prevent fungal spores and bacteria from being transferred to other plants.
leaf spot disease. Humid and warm climates cause leaf spot disease (Septoria lycopersici). Starting from the lower leaves, the fungus spreads to the upper ones. An infestation initially manifests itself as a yellow discoloration and small glassy spots of a greyish color with black dots. If only a few leaves are affected, the following measures can help:
If more than half of the plant is already suffering from the fungus, the tomato should be completely removed and ideally burned. Diseased plant parts do not belong in the compost!
bacterial wilt. As the name suggests, bacterial wilt (Corynebacterium michiganense) is a bacterial disease. Yellowish discolored undersides of the leaves and brown-yellow veins in the cross section of the shoots are signs of an infection. If the disease is left untreated, the leaves will turn brown and fall off. If an infestation is caught early, the gardener can do the following:
If more than a third of the plant is affected, then it should be destroyed completely. The fruits may then no longer be consumed.
pests
Sucking insects like to use the nutrient-rich leaves of the tomato. Weak specimens or plants in the greenhouse, where the living conditions for pests are particularly favorable, react to the nutrient deprivation by insects with yellow leaves. The whitefly and thrips are the usual troublemakers in the tomato patch.
caption: These insects are giving the tomatoes a hard time
Left: whitefly, right: thrips (also thrips, thunderfly)
white bow tie An infestation of whiteflies (Trialeurodes vaporariorum) is particularly likely in warm, humid summers. Individual insects do not cause any damage; but as soon as the tiny flies appear in swarms after touching the plant, action should be taken. Otherwise, the insects withdraw so many nutrients that the leaves are undersupplied and eventually turn yellow. remedy:
Thrips (Thrispe, Thunderfly). The black thrips (Thysanoptera) attack the tomato in two ways. On the one hand, the larvae feed on the roots and, on the other hand, the flying insects suck nutrients from the leaves. If the plant is heavily infested, the leaves will quickly turn yellow. Help against the thrips:
deficiency symptoms and nutrient supply
If a faulty water supply, diseases and pests can be ruled out as the cause of yellow leaves on the tomato plant, a deficiency of an important plant nutrient must be the reason for the discoloration. This is usually preceded by very loamy or very sandy soil - the pH value should be around 6.5-7 for optimal supply.
caption: Symptoms of various deficiency symptoms
Signs of a deficiency or excess of nutrients can be seen in different parts of the plant
nitrogen deficiency. If the roots take up too little nitrogen, the lower leaves of the plant will turn yellow first. Growth falters until even the fresh, bright green of the young leaves gives way to a pale yellowish hue. Nitrogen can be incorporated organically or minerally into the soil to reverse the undersupply.
Potassium deficiency/green collar. A potassium deficiency is most noticeable in the tomato fruits themselves: they remain green at the base of the stalk. The leaves, on the other hand, turn yellow at their edges and dry up. The soil can either have too little potassium or too much nitrogen. The latter causes the plant to grow too quickly to provide itself with available potassium.
magnesium deficiency. If the leaves appear whitish-brown and only the leaf veins shimmer green, the plant is suffering from a magnesium deficiency. This is often due to soil that is too acidic. Inorganic fertilizer is the best solution here.
Calcium deficiency/blossom end rot. Calcium is important for building stable cell walls. If there is a lack of the mineral, the fruits begin to rot parallel to the base of the stem. Over time, the leaves will also turn slightly yellow. Proper watering and basic soil such as the addition of rock dust can balance the imbalance. If the tomato is too bushy, pinching and a general pruning will also help.
Overfeeding/spoon leaf drought. The tomato leaves do not turn yellow, but become soft and curled up if they receive too much nitrogen fertilizer. The plant grows too fast to be supplied with other important nutrients. If the tomato is over-fertilized, skip the next one or two fertilizations.
phosphorus deficiency. If there is a phosphorus deficiency, the leaves will turn reddish-purple rather than yellow. Overall, the leaves are then rather smaller and dry up at the edge. This nutrient deficiency is rare and can be treated well with organic fertilizers such as compost.
FAQ
Can I throw wilted or yellow leaves in the compost?
That depends on why the leaves are yellow. If the cause of the yellowing is due to a lack of nutrients, then yellow leaves can be disposed of in the compost. However, if illness or pests are the cause, then these must be disposed of with household waste or, if permitted, incinerated.
Can the fruit of a tomato plant with yellow leaves be eaten?
The appearance of yellow leaves is particularly annoying when the harvest of lush tomatoes is due. You can eat these with one exception. However, if the plant suffers from bacterial wilt, the fruits also become inedible and may no longer be eaten.
Why do tomatoes get yellow leaves?
The reason why tomatoes develop yellow leaves is a lack of minerals, which are necessary for the formation of the green pigment chlorophyll. This is caused by either incorrect water management, diseases, pests or an imbalance in the mineral balance.
Which pests are responsible for yellow leaves?
The black thrips and the whitefly feed on the juices of the tomato. The missing nutrients result in an undersupply in the leaf, whereupon they appear yellow.
What can I do about yellow leaves on tomato plants?
It is always advisable to remove the yellow leaves immediately. The plant should then be examined more closely to determine whether incorrect watering, a lack of nutrients, diseases or pests are responsible for the discoloration.