Which crops grow well under solar panels? A guide for Indian farms

Ask most farmers whether crops can grow under solar panels and you'll get a sceptical look. Plants need sun, panels block it. That's true in a German winter. It's much less true in Rajasthan in May, when the sun is doing as much damage as good.

We're working on an agrivoltaic project ourselves, a blueberry greenhouse with solar generation above it, so we've spent a lot of time with the research on what actually grows under panels. Here's what it says.

Why some crops like a bit of shade

Every plant has a light level beyond which extra sunlight adds little to growth. Push past it in hot weather and the plant closes its pores to save water, its leaves overheat, and growth slows. A panel overhead takes the edge off that midday peak. The soil underneath stays cooler and loses less water.

So the right question isn't "do crops need sun?" It's "how much sun does this crop actually use, and how much do the panels leave?"

The crops that suit agrivoltaics in India

The Energy and Resources Institute (TERI) has assessed crop suitability for agri-PV in India. Their groupings, as reported in Renewable Watch, are a sensible starting point.

Most suitable

• Leafy vegetables, cabbage, spinach, coriander
• Onion and potato
• Turmeric and ginger
• Medicinal herbs
• Tea, coffee and grapes
• Lemon and sweet orange

Moderately suitable

• Tomato, radish and carrot
• Chickpea and groundnut
• Maize
• Kiwi and strawberry

Less suitable

• Paddy and sugarcane, which need a lot of water and, for sugarcane, are tall
• Coconut and palm, which simply don't fit under a structure

What Indian trials have grown

ICAR's Central Arid Zone Research Institute (CAZRI) in Jodhpur has run one of India's longest agrivoltaic trials, a 105 kW system on about an acre. Its factsheet lists crops grown between and under panel rows including mung bean, cluster bean, moth bean, isabgol, cumin, chickpea, aloe vera and brinjal. These are crops that already do well in dry conditions, which is the point: in arid zones, you want plants that are comfortable with less water and appreciate a little shade.

A 2023 review of Indian pilots by IISD and CUTS International found that yields of leafy vegetables, millets and medicinal plants did not fall under shade, and in some cases rose. Paddy and wheat hadn't been successfully trialled.

What happened in Germany

The best-documented long-running trial is Fraunhofer ISE's site at Heggelbach, near Lake Constance, with panels on a five-metre structure. In the hot, dry summer of 2018 the crops under the panels did better than their reference plots: celery yielded 12% more and winter wheat 3% more, while clover yielded 8% less. That's in a temperate climate. The shading benefit tends to be larger where heat and drought are bigger problems, which describes much of India.

Things that change the answer

The crop list is only half of it. The same crop can do well or badly depending on:

• Panel height. Higher structures spread light more evenly and let tractors through.
• Row spacing and density. Fewer panels per acre means more light for the crop and less power.
• Orientation. East–west rows give a moving band of shade through the day; some designs use vertical bifacial panels.
• Water management. Rain running off panels can cause erosion strips unless it's collected or spread.
• Region and season. A crop that struggles under panels in winter may thrive under them in summer.

We cover these properly in how to design an agrivoltaic system.

Our take

If you're starting out, pick a crop that is high value, shade tolerant and already sold in your area: leafy greens, herbs, spices or a fruit you can protect. Avoid trying to grow paddy or sugarcane under panels to prove a point. And plan the structure around the crop, not the other way round.

Thinking about an agrivoltaic project? Talk to us. We also design greenhouses that can integrate solar.