Sunflower cultivation in pots or in the open ground
We are dealing with a plant that grows easily, regardless of the variety you choose. In fact, there are different varieties, with different colors (bright orange, bright yellow, pale yellow) but above all with different blooms: depending on the size of the garden, in fact, it will be necessary to choose, within a very wide range, between blooms doubles and single blooms, multiple heads and single heads, small dimensions and imposing heights (over fifteen meters high). Sunflower, as the name suggests, needs at least six or seven hours of exposure to direct sunlight, to allow it to grow in the best possible way. Ornamental plant from the American continent but widespread in Europe, including Italy, the sunflower must be sown around the end of March, or by mid-April at the latest. If you opt for pot cultivation, you will need to use a rather large pot , in which to place a well drained and optimally fertilized universal soil. In the soil, possibly with the help of a specific gardening shovel, holes of small dimensions and not very deep (maximum five centimeters) must be made, within which two or three seeds must be introduced at most. Obviously, the holes will have to be very far from each other, since the sunflower needs a lot of space to develop in all its extension.
Which variety to choose
The cultivation techniques depend very much on the variety chosen: the most widespread and known, however, is the yellow Heliantus, which can be planted in pots or in the open ground. It is an annual species, which dies at the end of flowering: when the flower withers, it dries up completely, and in the corolla appear hundreds of seeds that can be collected and sown again. This is the easiest way to get the seeds, but of course they can be purchased in any garden center (where you can choose from the many varieties, orange, yellow and red, annual or perennial, large - with a single flower - or small - with cluster flowers) but also in many supermarkets. A few weeks after sowing, during which the land will be constantly watered, the seedlings will begin to sprout: they can be decanted as soon as they reach seven or eight centimeters in height, or in a vase or in the ground.
As for the waterings, they must be regular, but they must never cause water stagnation: excessive humidity, in fact, risks causing rottenness, with consequent infections and diseases. Sunflowers, in general, are able to withstand periods of cold or drought, as long as they are short, due to their robustness. Evidently, however, they develop much faster in the heat and in full sun. The seedling will gradually grow, and its development can be sustained with tutors, especially recommended if the area is very windy. Using an elastic cord, it will be advisable to tie each seedling to a tube positioned in the ground. Sunflowers will be in full bloom between August and September. When the flower wilts, the mature seeds will fall from the dry plant into the soil, giving rise to a new flower spontaneously.
Sunflower Cultivation: Pests and diseases
As far as pests and diseases are concerned, attention must be paid to good cultivation, the most widespread are phytophagous, which are usually hidden in or under the inflorescences. Suffice it to think of the sminthurus viridis, which feeds from the individual cells by taking portions of tissue or their contents, causing serious damage to the plant also because they subtract precious internal liquids. However, these parasites can be counteracted by using normal anti-parasitic products. More annoying, on the other hand, could be fungi: diseases such as powdery mildew, rust, gray mold and the rot of calatide and stem need specific anti-botrytis to be cured. In particular, rust causes yellowing of the leaves, and sometimes the death of the sunflower (which, however, in most cases, perishes slowly, reaching maturation difficulties); gray mold, on the other hand, makes a gray patina appear on buds, stems and leaves: a rather thick patina that leads to withering. As for oidium, also called white mal, it is nothing but a white-colored patina that wraps around the leaves, which, if struck, slowly turn yellow before drying. Finally, the calatide and stem rot is recognized by the cottony and white patina that causes the withering of the plant, simultaneously with a wet and greenish rot. Finally, sunflowers do not particularly suffer from the presence of insects; rather, it is necessary to protect them from the action of snails and birds, which could cause damage by approaching them and nibbling them.