The hyporachids (Arachi hypogaea) are easy to cultivate in the garden and can be very rewarding. While this plant has a beautiful and ornamental above-ground appearance, it is below ground that it yields its delicious fruits. Despite originating from Brazil, peanut cultivation in our country boasts some tradition. Although it has never been intensively cultivated, this plant has found success in family gardens due to its hardiness, excellent yields, and simple seed preservation. Some of its popular names include ground chickpea and ground pistachio. This emphasizes that peanuts bear their fruits beneath the soil.
Let’s better understand this cultivation and how to successfully integrate it into our home garden.
The Peanut Plant
The peanut belongs to the botanical family Leguminosae (or Fabaceae). Other much-loved species by gardeners, such as broad beans, peas, chickpeas, and lentils, also belong to this family. The characteristic they share is soil enhancement, naturally providing atmospheric nitrogen to the soil. Through their root system, they fix nitrogen into the soil, making it available for subsequent crops. As mentioned, peanuts are originally from South America, but the continents where they are most cultivated are Africa and Asia. In Italy, the most productive regions are Veneto and Campania. The Arachis genus encompasses over 40 species, but only Arachis hypogaea is the cultivated species.
The peanut is an annual plant. It can assume two types of growth:
- Erect-shrub, with a height between 45-60 cm and elongated branches.
- Bushy, with a height of 30-45 cm, shorter and prostrate branches on the ground.
The stems are robust, covered with fine hair. The leaves are composed in a pinnate manner and oval-shaped. A common feature of the leaves, shared with other legumes, is their tendency to close at night, almost as if preparing to sleep. Peanut flowers appear in the leaf axils and have golden-yellow petals, approximately 10 mm in diameter. The pods containing peanut seeds have rounded ends. Their length varies from 25 to 50 mm. Inside the pod, there are two to four seeds at most. Another characteristic of the pod is its thin, almost woody, reticulated and spongy shell. Additionally, it grows and matures underground. After pollination and wilting of the flower, the floral peduncle elongates. Due to positive geotropism, the ovary burrows 5-15 cm below the surface. Here, the pod develops and matures. The pod seems to act as a secondary root system, absorbing mineral nutrients from the soil. The seeds, the peanuts we eat, have variable shapes. They can be elongated or almost round and are covered with a thin protective reddish-colored film.
Environmental Requirements and Cultivation Period
Although originating from tropical regions, peanuts can be easily cultivated throughout Italy, from north to south. The crucial factor is choosing the right time to start cultivation, which cannot be during autumn or winter, as is the case with other legumes. Peanuts prefer a warm and dry climate. Therefore, sowing should occur when temperatures are at least 13°C during the day and never drop below zero at night. Thus, starting from March in southern regions and from April onwards in central-northern regions is advisable. For flowering, the plant needs at least 20°C, while the ideal temperature for pod maturation is between 25 and 30°C. The entire cultivation cycle lasts approximately 5-6 months. If sown at the beginning of spring, they will be ready by late summer.
Soil and Fertilization
Peanuts can adapt to various types of soil but prefer loamy or sandy soils. These allow easier underground pod formation. For the same reason, clayey and compact soils should be avoided. The soil needs to provide sufficient space for pod enlargement. Regarding soil pH, growth is favored in soils with a pH between 6 and 7, indicating slightly acidic or neutral soils. Abundant fertilization is unnecessary as the plant thrives in poor soils. At most, a moderate amount of wood ash can be used to prepare the soil before sowing.
Peanuts are sown in the ground using the hilling method, creating regular rows. This means that 2-3 seeds are placed in a hole 3-4 cm deep and covered with soil. The distance between the rows, and therefore the plants, should be at least 30 cm apart and 50-60 cm between rows. To obtain seeds, it’s best to preserve them in a dry place, retrieving them from the previous cultivation. The seeds should be kept with the entire pod, and the protective film should not be removed, even when buried. Naturally, the challenge lies in obtaining seeds for the first time. Fortunately, it’s possible to find them online.
Among the varieties available on the seed market, the most common are peanuts with larger pods. They are more aesthetically pleasing and have higher yields. Take care not to purchase seeds that are too old, as peanut seeds lose their germination capacity easily.
Among the cultivation operations, hillings play a fundamental role. This technique is primarily used to keep plants free from weeds and helps in pod enlargement. It involves adding soil at the base of the plant. This operation should be performed at least twice during the cultivation cycle. By doing so, there’s no need for natural mulching to keep the soil free from weeds.
Peanuts require minimal water. However, in excessively dry conditions, emergency irrigation is necessary. Since hillings are performed, setting up a drip irrigation system is not recommended. Water can be sprinkled, for example, using a rain sprinkler. Another option is infiltration, letting water flow into the furrows formed after hilling.
Harvesting and Preservation
When the peanut plant’s leaves start to turn yellow, the pods are ready for harvesting. To lift the plants from the ground, use a fork gently inserted into the soil. This eases the subsequent lifting operation. Once lifted from the ground with the entire root system, allow the remaining attached soil to dry. This drying process should be carried out indoors. Once the remaining soil has dried, shake it off the roots. From this moment, the pods can be removed. After harvesting, let them dry by placing them in wooden crates in a single layer. The crates should be elevated from the ground, and occasionally flip the pods. The room should be dark, ventilated, and dry. Dry pods can be stored as they are or in jute sacks.
Utilization and Roasting of Peanuts
As mentioned earlier, it’s advisable to reserve a portion of the harvest for the next year’s sowing. In this case, peanuts stored as explained in the previous paragraph are suitable. For consumption, peanuts need to be roasted. This can be done in the oven, either with the whole pod or just the seed (peanut). However, it’s preferable to roast the entire pod to avoid burning the seed inside. The ideal temperature for roasting is 200°C for about 20 minutes. To avoid issues, occasionally open a pod to check the level of roasting.
Biological Pest Defense
A significant advantage of cultivating peanuts in the home garden is their resilience to pests. More risky is the storage period, as peanuts are a temptation for mice and other rodents. Therefore, pay close attention to the cleanliness of the storage area.