C-DRONE GUIDE · 10 SEPTEMBER 2026
Asparagus and drones: spotting weeds on the ridge before emergence, price
In 2024, more than 6,600 hectares of asparagus were grown in France, yielding 27,476 tonnes — up from 4,433 hectares in 2016. As Europe's fourth-largest producer, France has around 3,000 specialised market gardeners growing a crop that is 95% white and purple asparagus, spread across the Landes, Gironde, the South-East, the Loire Valley and Alsace. In the Landes, the country's leading production basin, the "Asperges des Sables des Landes" PGI, granted in 2005, earned the Label Rouge quality mark in 2024. Between ridge planting and the emergence of the young spears, one rule applies: bare, scrupulously clean soil — with fewer and fewer herbicides available to keep it that way. Here is what a drone can bring to this perennial crop, and what it cannot replace.
Published on 10 September 2026, reviewed on 10 September 2026 — regulations in force as of September 2026.
A sand ridge, and fewer and fewer herbicides to keep it clean
White asparagus is grown on a sand ridge that shields the stem from light and keeps it white until harvest; picking is done by hand, every day for several weeks each spring, spear by spear, as soon as its tip breaks through the top of the ridge. The whole period before that — from planting the crowns to the emergence of the first spears, for a crop that stays in the ground for several years, typically eight to ten — demands bare, scrupulously clean soil: the smallest weed competes with young crowns for water and nutrients, and once the spears have emerged, hoeing or spraying is no longer an option without risking damage to that day's harvest.
That constraint runs up against a reality documented by the "Gestion des adventices en asperge blanche" technical sheet from the French Écophytopic network: with too few approved chemical options left, growers combine reduced doses, localised treatments, mechanical inter-row weeding, mulching and thermal weeding — a combination that works best when it targets weed patches precisely rather than treating the whole ridge as a matter of course.
What the research documents on drone-based detection of young weeds
Spotting a weed that has just emerged, before it is visible to the eye from the access path, is a problem precision-agriculture research has studied well beyond asparagus. A study by Peña, Torres-Sánchez, Serrano-Pérez, de Castro and López-Granados, published in 2015 in the journal Sensors, compared several sensor resolutions and flight altitudes for drone-based detection of young weeds at very early emergence: the authors show that detection accuracy depends heavily on sensor type, flight altitude and, above all, the timing of the flight — colour-infrared images taken a few weeks after sowing, when seedlings still carry only a handful of leaves, gave the best discrimination, with reported accuracy of up to 91% (see the study on Google Scholar).
The study does not look at asparagus, but at more conventional row crops; its central lesson — the detection window is narrow, and the quality of the result depends as much on flight timing as on the sensor used — applies directly to an asparagus ridge: bare sandy soil offers strong contrast for spotting a young green weed, provided the flight happens early, before the canopy closes in and makes it harder to tell a weed from a young asparagus spear.
What a drone flight brings to an asparagus field, in practice
The resulting service comes down to two passes, at two very different moments in the plot's life. Before the spears emerge, a very high-resolution RGB flight skimming the bare ridge soil, flown just after rain or irrigation that brings up weeds alongside the young asparagus shoots, maps the weed patches ridge by ridge instead of treating — or mechanically weeding — the whole plot as a matter of course. On a farm of several hectares, often split across multiple plots for Landes market gardeners who also grow other vegetables, this targeting cuts down the number of tool passes or product doses, at a time when approved chemical options keep shrinking.
The second use comes after harvest, when the plant is allowed to grow its foliage — the "fern" — to rebuild the crown's reserves for the following year. Asparagus is typically grown for eight to ten years on the same ridge, and as a planting ages it often develops a gradual, uneven decline known as field decline syndrome, documented in Spain by a study by Brizuela, De la Lastra, Marín-Guirao, Gálvez, de Cara-García, Capote and Palmero, published in 2020 in the Journal of Fungi: analysing 41 fields across Spain's three main production areas, the authors link it to a consortium of several soil-borne Fusarium species (see the study on Google Scholar). The study does not look at aerial imagery, but the symptom it documents — a loss of vigour that spreads in patches, before it is visible to the eye from the access path — is exactly what a near-infrared pass during the fern stage can objectively flag several weeks ahead, prioritising a ground diagnosis rather than discovering the decline once yield has already dropped.
Where to fly: Landes, Loire Valley, Alsace — and what to check first
The Landes, France's leading production basin with the "Asperges des Sables des Landes" PGI, account for most of the farms worth flying, alongside neighbouring Gironde, the Loire Valley, Alsace and several basins in the South-East. The terrain is flat and the low ridge poses no height constraint: most missions fall under the open category with no prior process needed. The point worth checking instead is regional geography: the Landes département hosts several active military zones — the Mont-de-Marsan air base, the Captieux firing range and the DGA missile testing site at Biscarrosse — whose footprints and associated restricted zones should be checked before any flight on the Géoportail map of restricted zones, as for any agricultural mission in this area.
The same logic of early weed-patch detection applies, with different crops and constraints, to rice farming in the Camargue; our page on precision agriculture by drone covers the multispectral method across all types of vegetation cover.
Prices observed in 2026
An asparagus field is priced by plot and by pass more than by hectare alone: reacting at the right moment — just after rain for weed spotting, at peak fern growth for vigour — matters as much as area. Ranges observed in France in 2026, excl. VAT:
| Service | Range (excl. VAT) |
| Pre-emergence RGB weed-spotting flight (up to 5 hectares) | €250 to €450 |
| Additional pass per extra 5-hectare block | €80 to €150 |
| Multispectral vigour flight during fern growth (NDVI mapping) | €300 to €550 |
| Combined seasonal monitoring (weed spotting + post-harvest vigour) | €600 to €1,000 |
These amounts cover the flight and delivery of a usable map within 24 to 48 hours; they do not include mechanical or thermal weeding, nor an agronomic diagnosis of the decline. For a growers' group or a Landes cooperative bringing together several neighbouring farms, a grouped campaign meaningfully cuts the cost per hectare. Request a quote stating the area, the number of plots and the intended period: before emergence for weeds, at peak fern growth for vigour.