Sun to the rescue: How solar driers are saving harvests

When Wairimu Muchai first ventured into researching solar-drying technologies, she had no idea that her curiosity would evolve into a transformative agritech solution for farmers across Kenya.

Today, as co-founder and Head of Business Development at Aqua Hub Kenya, she plays a central role in championing climate-smart innovations designed to reduce post-harvest losses and strengthen farmers’ resilience.

Aqua Hub Kenya is a climate-smart agritech enterprise offering greenhouse irrigation systems and solar-drying solutions. Muchai says the venture’s mission is simple yet vital.

“With our solutions, farmers are able to increase production, enjoy year-round output and significantly reduce post-harvest losses,” she says.

The company’s flagship innovation the improvised solar dryer has become a lifeline for hundreds of farmers seeking affordable ways to preserve perishable produce.

Resembling compact greenhouse structures, the solar dryers harness the sun’s energy to create a controlled drying environment.

“The dryer absorbs heat through a clear, greenhouse-grade polythene cover. That heat is then circulated inside the structure, allowing produce to dry safely and efficiently,” Muchai explains the process.

Unlike traditional open-sun drying, the system protects food from dust, pests and unpredictable weather, ensuring higher-quality, hygienic dried products.

Muchai’s expertise in constructing these improvised solar dryers came from online learning and years of hands-on interaction with farmers.

“I gained the skills through online research and working closely with farmers. Most of our solutions are co-created with them,” she tells City Biz.

Some components are sourced locally, while others are imported. “We use locally available materials like galvanized steel, but we also incorporate third-party technologies such as nets, polythene, profiles and damliners,” she says.

Climatic shocks

Muchai has been spearheading this initiative for the past five years. Her motivation stemmed from the urgent need to address the climatic shocks increasingly affecting Kenya’s agriculture sector.

“Unpredictable rains, prolonged droughts, and intense heat negatively impact perishable farm produce,” she says, adding: “This leads to post-harvest losses of between 30 per cent and 40 per cent, directly reducing farmers’ incomes.”

Aqua Hub’s solar dryers target farmers, youth groups, cooperatives, and development organisations looking to support community agribusiness initiatives.

The dryers are especially valuable for groups venturing into dried fruits and vegetables snacks such as dried mangoes, pineapples, bananas, and indigenous vegetables.

Muchai says there has been a notable increase in the demand for dried vegetables.

To reach clients, Muchai uses digital platforms including Facebook, TikTok, their website, as well as referrals and farmers’ field days. The impact of these interventions is significant.

According to Muchai, farmers who adopt solar dryers experience a reduction of climate-related post-harvest losses by 40–80 per cent, improved resilience to unpredictable weather patterns, better access to safe and shelf-stable foods, and new income opportunities.

Farmers report income increases of 25–40 per cent, stronger local value chains, and improved household nutrition.

However, the journey is not without challenges. “Low adoption remains a major hurdle,” she says, adding “The upfront cost of dryers, limited technical knowledge in food safety, and poor access to structured markets for dried products slow down widespread uptake.” The smallest dryer costs about Sh150,000.

To address these gaps, Muchai hopes to collaborate with development partners to establish community-owned solar drying hubs. “Such hubs would strengthen local food systems, support youth-led agribusiness, and provide sustainable processing infrastructure,” she emphasises.

Her vision is a climate-resilient economy where communities can produce, process, and market food throughout the year, regardless of climate variability.

Although solar dryers remain a seasonal product, Aqua Hub’s revenue from customised units ranges between Sh2.2 million and Sh7 million per year. But for Muchai, the real value lies in its impact.

“The solar dryer is a simple innovation with the power to transform livelihoods,” she says. “As we embrace smarter ways of preserving food, investing in post-harvest technologies today strengthens our nation’s food security for tomorrow.”

Through determination, innovation, and farmer-centered design, Wairimu Muchai is proving that improvised solar dryers are more than just tools; they are catalysts for a more resilient, food-secure future.