Why do zucchini turn yellow and how to deal with it?
Zucchini is very loved by the inhabitants of our country. This product is used in many dishes and helps out throughout the year. However, during cultivation, many gardeners are faced with one common problem that can do a lot of harm to the crop - yellow discoloration of the leaves. In this case, you must immediately begin to correct the situation.
The reasons
When the leaves of zucchini turn yellow, this indicates that something is not normal with the plant. Ideally, the leaves should be a bright green saturated color, rather large and strong. This appearance is a guarantee that the ovaries will appear soon, and then the fruits. If the color suddenly began to go yellow, which, by the way, can happen even at the seedling stage, it is important to immediately determine the cause of this phenomenon. It should start with the fact that vegetables do not tolerate a drop in ambient temperature very well. Therefore, any cooling leads to the fact that the plant begins to weaken, and the foliage turns yellow. Based on this, we can conclude that the appearance of zucchini in the open field should occur no earlier than summer. If we are talking about a greenhouse, then the landing can be made in early May.
Yellowness may be the result of improper garden planning. Zucchini loves well-lit areas, but if it stays in the sun for too long, the leaves immediately dry and turn yellow.Therefore, a crop can only be planted in a garden bed that will be exposed to direct sunlight for no more than four or five hours (while the daylight hours should be at least twelve hours). Additionally, you can design a canopy that will prevent the plant from burning, and expose it at noon. The leaves may turn yellow in case of too dense plantings. If the seedlings were initially planted without observing the required intervals, then the growing bushes will lack air and space. This is especially true of the bottom sheets, which experience problems with ventilation. As a result, the foliage will turn yellow, and then, if it is not removed, it will also rot.
Wrong watering
An ill-conceived watering system also contributes to the appearance of yellowed foliage. This happens because the irrigation of plantings is carried out at lunchtime, that is, at the most inopportune time. The combination of moisture from watering and bright sunlight leads to thermal burns and spots on the squash leaves. That is why watering the crop can only be done in the morning or evening hours.
Water should be settled and comfortable temperature. It is important to prevent liquid from getting on the green parts of the plant and inflorescences, and that the bushes are not flooded with water. It should be borne in mind that sometimes the leaves begin to dry out due to the small amount of moisture in the soil. Therefore, you need to water regularly, and the need for liquid is determined by the state of the topsoil. It is very important that neither cracks on the surface nor moisture stagnation occur. Incorrect "relationship with water" can also lead to yellowing of the fruits themselves. Too much moisture causes the zucchini to rot and then change color.Therefore, during this care procedure, it is important to control the liquid content of the top layer in order to avoid excessive moisture.
By the way, the fruits can also turn yellow in the case when they were not collected on time. If they are stale in the garden, then their density will deteriorate, and the traditional shade will change to pale yellow. Such fruits quickly lose their juiciness, their peel coarsens, and the seeds become unnecessarily large.
Diseases and pests
Of course, a sudden change in shade can also signal emerging diseases. First of all, it is downy mildew. This fungus is developing rapidly and affects not only zucchini, but also tomatoes and other vegetables. It will be possible to determine it by the state of the leaves - on the inside, and then on the outside, oily spots of a light yellow hue are found. At first they are small, and then quickly increase. The leaf itself dries up at this time. Usually the disease develops with an abundance of rainfall on those crops that are not properly cared for. If measures are not taken in time, then all landings will be destroyed. With powdery mildew, all infected bushes must be removed immediately, and the soil must be dug up every autumn.
The appearance of anthracnose is also possible, most often when grown in a greenhouse. First, vaguely shaped spots appear on the leaves, which then turn dirty yellow, as if the bush had been burned by the sun's rays. After that, the leaves dry up, and the disease gets to the zucchini themselves. They also turn yellow, and then the rotting process begins. The culture also begins to change color when it is affected by chlorosis, which is a consequence of the lack of sufficient loosening of the earth.Air does not enter the root system, the whole plant is weakened, and the leaves become yellow.
Among pests, this crop is most often attacked by a spider mite. From the wrong side, a thin cobweb appears on the sheets, the pest itself settles in it. After that, the leaf becomes stained, turns yellow and finally falls off.
Nutrient deficiency
Another common cause of yellowing foliage is considered to be insufficient application of useful elements to the soil. First, the lower leaves turn yellow, and then the problem spreads throughout the bush. Moreover, the sheet changes color first along the edges, and then it deforms and falls off. This situation occurs when there is a lack of nitrogen or moisture in the soil, as a result of which the transportation of useful elements becomes difficult and the chlorophyll content decreases. Everything leads to the fact that the sun burns the foliage, which turns yellow, and then dries up. In this case, you need to apply nitrogen fertilizers sold in special stores.
In addition, it is important to normalize the condition of the soil - zucchini cannot grow on too acidic soil. The leaves will quickly turn yellow, and the bushes themselves will wither. This issue will have to be resolved even before the seedling planting stage - it will be necessary to add lime, as well as humus with ash. In general, the soil for zucchini should be nutritious. A suitable mixture is purchased at the store or combined with your own hands from peat, river sand and turf. All components must be taken in equal proportions and mixed. It is recommended to regularly feed the sprouts with mineral fertilizers.
What can be processed?
If powdery mildew became the cause of the yellow color, then you need to do the following: spray the bushes several times with copper oxychloride and Bordeaux liquid.In addition, at the stage of still preparing the seeds, they should be soaked in warm water for prevention. Do not forget about regular ventilation. You can get rid of yellowing due to anthracnose by removing damaged bushes and spraying them with Bordeaux mixture or colloidal sulfur. Do not forget about prevention - the elimination of residues in the soil and the processing of the greenhouse.
The fight against spider mites can be carried out in several ways. First, 200 grams of laundry soap are grated. They are mixed with a kilogram of wood ash and diluted in 10 liters of water. Treatment with such a solution is carried out every two days until the pest completely disappears. Secondly, you can use the tops of potatoes in the case when it has not been subjected to phytophthora disease. The greens are cut into small pieces and filled with water, completely covering the green mass. You will have to insist for a week or 10 days, and the lid must be closed. This tool can be used every day. Thirdly, pharmacy chamomile and a few other ingredients will come to the rescue. A kilogram of wood ash and four garlic heads are poured with 10 liters of chamomile decoction, which will require 200 grams of dry powder to prepare.
This solution is infused for a week, it will have to be stirred regularly. Then you will have to process the zucchini three times, which should fit in a weekly interval. It is believed that this method is the most effective.
Helpful Care Tips
In the event that the leaves turn yellow even at the seedlings, you should check whether the entire leaf plate is damaged. If so, then the sprout will have to be thrown out, but if not, then the situation can still be corrected.In young zucchini, this problem usually appears due to a lack of nitrogen in the soil. Therefore, it is imperative to buy fertile soil and periodically fertilize. Feeding should begin about two weeks after sprouts appear. Do not forget about the regular spraying of the earth with a spray bottle. Sometimes even transplanting into a container with a large diameter can solve the problem.
It is important to monitor the amount of watering to prevent excessive moisture. After prolonged rains, it would be good to inspect the plant for unpleasant consequences. Pests can be repelled by periodically spraying plantings with herbal infusions, which include chamomile, potato tops and nettles. It is useful to process zucchini with solutions of copper sulfate, boric acid, urea with the addition of potassium permanganate.
Weeding the beds will have to be done in a timely manner, preventing weeds from depleting the soil. Holes can be mulched with sawdust or dry straw. The procedure can be carried out once every two weeks until the ovaries begin to form.
As soon as closer to autumn all the leaves begin to change color and dry out, this may indicate that it is time to harvest. The procedure should be completed by tidying the tops on the site.
Yellowed leaves must be immediately eliminated - removed from the bushes and even burned. This greenery should not be used for compost or other needs, and it is better not to leave it in the garden. When the damaged parts are eliminated, you can begin processing the bushes. The tool itself is prepared immediately before the procedure. It is better to spray in the morning, until the bright sun appears in the sky, and on days when the wind is not too strong.If damaged young shoots and adult bushes are grown in the same greenhouse, then all plants must be treated at the same time.
For information on what to do if the zucchini begins to turn yellow and rot, see the next video.
Please tell me why the zucchini grew to 20 cm, and then they began to turn yellow and soften?