A solar farm and a regular farm want the same thing: flat, open, sunny land. For years that meant picking one. A growing number of growers are trying both at once, raising solar panels high enough to farm underneath or letting sheep graze between the rows. The surprise from a decade of field tests is that some crops actually do better in the partial shade, and the plants return the favor by keeping the panels cooler. Here is how it works, where it has paid off, and where it falls flat.
Plants can only use so much sun
The everyday idea behind this is simple. A leaf is a bit like a bucket under a tap. Once it is full, more water just spills over. Many plants reach the most light they can use well before noon on a clear summer day. After that, extra sun mostly adds heat, dries out the soil, and makes the plant close its pores to save water, which slows its growth.
Solar panels, meanwhile, never get full. They turn any light that hits them into electricity, though they lose a little efficiency as they heat up. So the pitch is to share the sunlight: let the panels skim off some of it, and let the crop below get the softer light it can still use.
The name for this is agrivoltaics, a mash-up of agriculture and photovoltaics, the technical word for solar panels. You will also see it called dual-use solar, agrisolar, or, in Japan, solar sharing.
An idea from 1982 that waited for cheap panels
The concept is older than most people expect. In 1982, Adolf Goetzberger, who founded Germany’s Fraunhofer Institute for Solar Energy Systems, and his colleague Armin Zastrow published a paper on how solar collectors and crops might share the same field. At the time, panels were far too expensive for anyone to put them over a potato patch.
Japan got there first in practice. In 2004, an engineer named Akira Nagashima built early prototypes with panels mounted on thin pipes above farmland, spaced out so plenty of light still reached the ground. In 2013, Japan’s agriculture ministry set rules that allowed panels over farmland as long as farming continued underneath. Thousands of mostly small projects followed, growing more than 100 different crops.
The German potato test
One of the best-known trials sits on Heggelbach, an organic farm community near Lake Constance in southern Germany. In 2016, Fraunhofer researchers and partners built a 194-kilowatt array of 720 panels on a frame five meters (about 16 feet) high. That is tall enough for a combine harvester to drive underneath. The rows are spaced wide apart, so crops between and below them get a fairly even mix of sun and shade.
The farmers planted winter wheat, potatoes, celery, and clover grass, and compared them with the same crops in an open field next door. In 2017, the field with panels produced about 160 percent of what the land would give if it were used for only farming or only solar. In other words, one field did the work of 1.6 fields.
Then came the very hot, dry summer of 2018. The partial shade helped the crops cope, and the extra sunshine boosted the panels. Celery yields were 12 percent higher than in the open field, winter wheat 3 percent higher, and clover 8 percent lower. Based on the potato harvest, the researchers put the land-use figure at 186 percent.
The results were not all good news, which is worth knowing. In cooler, cloudier years, the shade can cost a crop more than it helps. The setup also produces about a quarter less power per acre than a normal solar farm, because the rows are spread out.
Peppers and tomatoes in the Arizona desert
Hot, dry places are where shade looks most useful. At the University of Arizona’s Biosphere 2 research site, a team led by Greg Barron-Gafford grew chiltepin peppers, jalapeños, and cherry tomatoes under solar panels and in open plots nearby. Both got the same amount of water.
Their results, published in the journal Nature Sustainability in 2019, were striking. Chiltepin plants made three times as much fruit under the panels. Cherry tomatoes made twice as much. Jalapeños produced about the same amount, but lost 65 percent less water through their leaves. The soil under the panels also stayed moister after each watering, which hints that farmers in dry places might be able to irrigate less.
The panels benefited too. Plants release water vapor through their leaves, and that cools the air around them. Barron-Gafford compared it to the misters on a restaurant patio. Cooler panels convert sunlight a bit more efficiently, so the crops underneath nudged up the electricity output.
A Colorado hay farm that switched to vegetables and sunshine
In Longmont, Colorado, a family hay farm had stopped paying its way by the mid-2010s. In 2020, it became Jack’s Solar Garden, a 1.2-megawatt community solar site with 3,276 panels on mounts 6 and 8 feet high. It makes enough electricity for more than 300 homes, and it was built with help from researchers at the National Renewable Energy Laboratory, Colorado State University, and the University of Arizona.
From 2021 through 2025, a nonprofit called Sprout City Farms grew vegetables under about three acres of the panels, including tomatoes, peppers, beans, potatoes, beets, and leafy greens. The shade protected tender greens from the harsh high-altitude sun, while sun-lovers like tomatoes were planted where they got more light. Some plots got only half the usual water to test whether the cooler, shadier ground needed less. The farm group wound down its operations at the end of 2025, but the site still hosts research and tours.
The easiest version: let the sheep do the mowing
Not every version needs tall frames or special planning. Grass grows under ordinary solar farms, and if it gets tall, it can shade the panels. Someone has to cut it. More and more operators simply bring in sheep, which is often cheaper than mowing. The sheep get food and shade in return. Sheep are the usual choice, since cattle are big enough to damage the equipment.
Researchers in central France studied two sheep-grazed solar sites for a year. Directly under the panels, light dropped by more than 90 percent, and the soil stayed a few degrees cooler. The grass there grew taller faster and was more nutritious, though the total amount of grass over the whole year came out about the same as in the open. In Australia, a trial with merino sheep found that animals grazing under panels produced more and better wool.
Where it does not work so well
Agrivoltaics is not a magic trick. Staple crops like wheat, corn, rice, and soybeans generally need a lot of sun, and shade tends to cut their yields. Leafy greens, many herbs, some berries, and spices like turmeric and ginger handle shade much better. The Heggelbach wheat did fine in a scorching year, but that does not mean it would every year.
Cost is the other big hurdle. Raising panels high enough for tractors means taller, stronger frames, and that makes the electricity more expensive than a standard solar farm. Farm work also gets more awkward when there are posts in the field. In cool, damp climates, shade can raise humidity and plant disease, and the benefit may shrink to nothing.
There is a fairness question as well. Residents near Heggelbach told researchers they preferred the farm array to a regular solar park, but they also warned against “pseudo-agriculture,” where a few token plants are grown under panels just to win approval. Clear rules about what counts as real farming matter. China, for example, restricted new solar on its cropland and grasslands in 2023 and steered projects toward deserts and other low-value land.
The bottom line
Sharing a field between food and electricity is not a fix for every farm. It works best where the sun is fierce, water is scarce, and the crop does not mind a little shade. Sheep grazing is the easiest win, and it is spreading fast. Higher-efficiency panels could help, too, since a panel that makes more power from less area leaves more room and more light for what grows below. That is one reason the race toward perovskite tandem panels matters beyond rooftops.
Next time you drive past a solar farm, look under the panels. There may be sheep, lettuce, or peppers down there, enjoying the shade.
Further reading
Electrify: An Optimist’s Playbook for Our Clean Energy Future — Saul Griffith’s numbers-first plan for running homes, cars, and the grid on clean electricity, including where all that new solar could realistically go.
The Market Gardener: A Successful Grower’s Handbook for Small-Scale Organic Farming — Jean-Martin Fortier’s practical guide to growing a lot of vegetables on a small plot, a good grounding in the farming side of the shade-and-sun trade-off.