Nutrition deficiency
Yellow leaves on tomato plants can indicate a nutrient deficiency, specificially Nitrogen, Manganese, Iron, Boron, Magnesium or Chlorine. According to experts, one should first check the leaves for the presence of spots, veins or yellow margins as this can help to decide if the problem is caused by a nutrient deficiency or other pests or disease. Symptoms of nitrogen deficiency are yellowing reduced leaves, purpling of the veins and untilized flower growth. For manganese deficiency, the plants’ leaves will appear as if they were burned. For iron deficiency, only some of the inter-veinal portions of tomato leaves will yellow and plant growth will be stunted. Meanwhile, signs of boron deficiency can include foliage yellowing between the veins, enlargement of internodes, and dead heart of the plants. Magnesium deficiency may cause yellowing of the leaves and the plants’ stems may become brittle, while symptoms for chloride deficiency include yellow blotches on the leaves, often found near the tip.
Soil test and fertilizing
In order to confirm the presence of any nutrient deficiency, experts recommend conducting a soil test. If the soil test confirms a deficiency is present, one should amend the soil with the particular nutrient that is deficient. To do this in an organic manner, one can use foliar sprays of chelated Iron, and liquids such as fish emulsion or kelp extract that are naturally packed with the essential micronutrients. Additionally, one can add organic materials such as compost, aged fish, humic acid, or coffee grounds to improve the soil in an organic way.
Apart from soil amendment, one can also use fertilizers to resolve the nutrition deficiency. Synthetic fertilizers can be a fast solution to the problem, however, they tend to give a short-term remedy only. Organic fertilizers, on the other hand, provide a long-term solution if they are consistent, and can help to keep the pH level at an optimum range. Organic fertilizers are also more sustainable and are not harsh to the environment.
Companion planting
Another essential way to avoid nutrient deficiency in tomato plant is to use companion planting. Companion planting is the practice of planting certain vegetables and flower plants around tomato to help them grow. Planting certain vegetables, such as cucumber or beans, can help to increase Nitrogen in the soil. Similarly, planting flowering plants such as marigolds, petunias, alyssums or cosmos, can help to attract pollinators to the tomato plants, which in turn can also increase the Nitrogen cycle.
Watering, mulching and climate
Proper watering can also play an important role in reducing nutrient deficiencies in tomato plants. Tomato plants are prone to drying and hence require moisture in the soil in order to produce healthy, lush foliage. Although, too much water can be counter-productive. To minimize damage from incorrect watering, experts advise to use mulch around the base of the plant. This helps to retain moisture and protect the plant from weeds. It also keeps the soil temperature and the pH level more stable.
In addition to watering and mulching, proper climate can also take a crucial role in averting nutritional deficiency in tomato plants. Tomato plants require hot climates, and can survive minimum temperatures of 10-12°C. If the temperatures fall below this, then tomato plants may not be able to take the shock and may result in problem like yellowing of the foliage.
Insects Infestation
Yellow leaves on tomato plants can also indicate an infestation with various insects for example whiteflies, aphids, thrips, spider mites or flea beetles. Whitefly infestations can cause yellowing of the foliage, as well as leaf loss, wilting, and death in severe cases. Aphids, on the other hand, draw out the sap from the plants and this can cause yellowing of the leaves. Similarly, thrips are tiny insects which can damage tomato plants by sucking the sap from the plant. They leave an oily black residue on foliage which can eventually lead to yellowing of the leaves and stunted growth. Spider mites are also known to attack tomato plants. These are tiny mites which are impossible to see with naked eyes. They are even more hazardous to tomato plants as they spin webs on them. Finally, flea beetles are another common attacker of tomato plants. They leave little holes in the tomato foliage, which can quickly turn yellow in color.
Treatment
Treatment options for insect infestations depend on the severity of the infestation. If the infestation is modest one can use natural insecticides or insecticidal soap to control them. However, in case of severe infestations one should use conventional insecticides to get the job done. It is better to use organic bug sprays or sprays which are specifically designed to target the particular pests at hand.
Tips
To avoid yellow leaves on tomato plants, one should keep track of environmental factors such as standard water levels, proper climate, fertilization and pest control. One should also use companion plants and organic materials which will boost the Nitrogen cycle and will eventually promote healthy growth of tomatoes. Additionally, it is also essential to keep the soil loose and weed free at all times.
Diseases
Yellow leaves on tomato may not only be caused due to nutrient deficiency or insect infestations. Diseases, such as fungus or viruses, can also cause yellowing foliage on tomato plants. Fungi generally appear as dark spots on the foliage which can eventually lead to yellowing. Similarly, certain viral diseases can also cause yellowing of tomato foliage.
Prevention
To avert fungi and virus diseases, experts suggest taking preventive measures such as maintaining a clean garden, removing diseased plants and erasing any remaining trace of the plants. In addition to this, one should also avoid working on wet tomato plants as damp soil can be the ideal place for fungi to start growing. Rotating the tomato crop can also help to avoid virus and bacterial diseases as this will allow the enzymes to rest in the soil and match up to disease-causing organisms.
Variety selection
A good variety selection can also help to avoid such diseases, as some of the varieties are resistant to certain plant viruses or fungi. Hence, it is always suggested to opt for varieties which can resist with the local climate and won’t lead to yellowing of the leaves.
Complimentary Planting
Complimentary planting, such as using beans or other legumes near the tomato plants, can also help to fight the diseases as legumes are nitrogen-fixing plants and can provide healthy nitrogen to the tomato plants. In addition to this, they can also attract beneficial insects such as bees, buttercups, wasps and other pollenizers, which will eventually help to pollinate the tomato plants and will decrease the risk of disease.
So, proper pre-emptive steps are essential to fight against yellowing of tomato leaves. With the right combination of proper fertilizer and plant selection, one can surely provide the tomatoes with the balanced nutrition and proper environment they require for their healthy growth.
