Aerial seeding before harvest is becoming more popular again, especially as summers have become drier. This technique uses drones to plant cover crops while the previous crop is still growing. This method helps seeds take advantage of the remaining soil moisture and the protection provided by existing plants, which can improve their growth and biomass production before autumn. According to Arvalis, trials since 2019 have shown that seeding less than ten days before harvest can result in similar plant growth, biomass, and nitrogen absorption as seeding after the harvest. However, seedings done 16 to 70 days before harvest often lead to lower biomass, as young plants might not get enough water or light under the still-growing crop. In June 2026, a company called Oligo+ used drones in Lavaufranche, Allier, to seed red clover in an oat field that was still growing. The drone used could carry up to 50 kg of seeds and spread them over a 6-meter width at a rate of up to 7 hectares per hour under ideal conditions. Similar trials were conducted in September in the Côtes-d'Armor region, where a mix of vetch and hairy vetch was seeded in grain corn. These experiments aim to save time in planting cover crops and allow them to grow more before winter. An experimental field set up in 2025 in Lierville, Oise, compared different planting methods. Aerial seeding done by drone on June 30 achieved an average biomass of 4.5 tonnes of dry matter per hectare. In comparison, direct seeding done on August 5 resulted in 3.2 tonnes per hectare, and simplified seeding on August 25 resulted in 2.1 tonnes per hectare. However, these results are specific to the conditions of the experiment and emphasize the importance of timing rather than the use of drones themselves. Terres Inovia recommends planting cover crops early, especially in areas where soil nutrients are easily lost, to ensure they are well-established before drainage periods. A study by Semae estimates the economic benefits of cover crops, including up to 105 euros per hectare for nitrogen returned to the soil, 128 euros per hectare per year for carbon stored, and 960 euros per hectare for preserving crop yields by reducing soil compaction. However, the cost of aerial seeding before harvest is estimated at 10 to 12 euros per hectare, while drone seeding costs range from 30 to 45 euros per hectare, not including the cost of seeds. Aerial seeding relies on rainfall, ideally 20 to 25 millimeters, and is best suited for small seeds with a PMG (plant material weight) less than 35 grams. Fields with hard-to-control weeds might not be ideal for this method, as the lack of soil preparation limits the ability to manage unwanted plants. The presence of straw also plays a role in the success of the planting, with less favorable results when straw is removed. While drones offer advantages in certain situations, they do not replace traditional seeders and are limited by factors such as field conditions and the selection of plant species.