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Greenhouse mold and fungus problems can wreak havoc on your plants—especially in the cooler, damper months. Common culprits like grey mold (botrytis), fusarium, sooty mold, and powdery mildew thrive in stagnant air and excessive humidity. Fortunately, preventing outbreaks is possible with five key strategies: maximize sunlight exposure, ensure proper ventilation, monitor temperature and humidity, water conservatively in winter, and keep your greenhouse clean. From adjusting your watering schedule to changing out contaminated soil, these proactive steps can help you maintain a healthy, thriving greenhouse environment all year round.

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Greenhouses are not one size fits all but in the late fall through spring many greenhouse growers report problems with fungus in their greenhouse. Climate control and cleanliness are important aspects of preventing fungal problems in a greenhouse because damp cool conditions encourage mold to thrive and spread.

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Designing your ideal greenhouse involves selecting a color that complements your garden and reflects light effectively, building a raised foundation for better headroom and airflow, and choosing durable glazing like twinwall polycarbonate for energy efficiency—ensuring both aesthetic appeal and optimal plant growth.

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When buying a new greenhouse, the big news is that whatever you choose, it is never big enough because as gardeners we know how to expand our production to fill our space. That is when my last greenhouse was 16' x 20' and I grew citrus trees in central beds, trays and trays of starter plants on suspended shelves, strawberries in rain troughs sitting on brackets attached to the walls, tomatoes in beds along the inside walls and cucumbers climbing a trellis to the really high roof.

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Choosing the right greenhouse depends on your climate, garden layout, personal style, and long-term goals—whether you’re maximizing growing space or designing a beautiful retreat—so consider structure materials, model types like the Cape Cod or Pacific, and placement with expert guidance to ensure the perfect fit for your space and stage of life.

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It's pretty tough to put all your thoughts into one "basket" - or in my case, one new greenhouse purchase. I'm Donna Balzer and I am a gardener and horticulturist by training. I am about to build my third BC Greenhouse Builders greenhouse this spring and you might think I should know everything about greenhouses by now.

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What are the essential seed terms for greenhouse gardening? Understanding common seed terminology is key when planning your greenhouse garden. Heirloom seeds are stable, open-pollinated varieties that grow true from saved seed, while hybrid (F1) seeds are lab-created crosses offering traits like disease resistance or high yield but cannot be reliably saved. F2–F5 seeds are later generations from hybrids, gradually stabilizing into your own heirlooms. Pelleted seeds are clay-coated for ease of planting, especially by machine, while treated seeds are coated with chemicals to resist rot in cold soil—something many organic growers prefer to avoid. Terms like “new” may refer only to catalogue listings, not to truly new varieties. You’ll also see micro-tomatoes, compact plants ideal for greenhouses, and days to maturity, which are useful for comparing growth speeds across varieties but are not precise. Ultimately, buying seeds in bulk from fewer suppliers or saving your own seed helps manage rising shipping costs while still offering variety and value in your greenhouse garden.

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So much to consider

It is December and the seed catalogues are arriving fast and furious. Meanwhile, online suppliers are pounding out dozens of notices to remind us it is time to order seeds soon.

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Growing a variety of lettuces like iceberg, Bibb, leaf, and romaine in your greenhouse ensures fresh, year-round greens despite outdoor shortages, while maintaining ideal moisture, shade, and temperature conditions maximizes yield and quality.

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Planning to grow more greens in the new year

Dry weather in California has made lettuce plants weaker and a virus has ravaged crops, leaving farmers with little to sell, according to an article in the November 18, 2022, Calgary Herald. Consequently, iceberg and romaine lettuce are harder to find this month all over North America.

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How does nature in a greenhouse benefit health and well-being? Greenhouse gardening fosters year-round growth, creativity, and mental wellness. The greenhouse serves as both sanctuary and studio, where finger limes, tomatoes, and microgreens thrive—and where the act of nurturing plants inspires everyone from camera crew to casual observers. As supported by experts like psychiatrist Susan Stuart-Smith, engaging with natural complexity in gardens has proven restorative effects. Whether it’s growing exotic citrus or saving tomato seeds, greenhouse gardening extends the seasons and deepens our connection to nature—reminding us that the seeds we sow today hold the promise of tomorrow’s blooms.

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Late Fall Harvests

It's late September and I taste my first-ever finger lime, grown right in my greenhouse, and I am amazed by the crisp texture and luscious lime taste of the juicy vesicles. (See my first impressions here) And just then an unrelated email arrives. A Los Angeles-based marketing firm asks, "Will you showcase the benefits of nature on behalf of a client for an online event?"

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What are the best tips for a successful late summer greenhouse harvest? As the season transitions, focus on four essential strategies: switch to a low-nitrogen fertilizer (like a 2-8-4 mix with kelp and micronutrients) to build plant strength without promoting excessive growth; maintain strong air circulation with fans to prevent fungal issues as nights cool; start fresh crops like lettuce and arugula to extend your harvest into fall; and apply targeted shading using aluminet or shade cloth to protect plants from intense late-summer sun. These greenhouse gardening tips will help you maximize yields and enjoy a longer, more productive harvest season.

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Late Summer Gardening Tips

It is late August and I am chatting with my daughter who lives in Northern Alberta, Canada. Her outside garden has never looked so good because of the heat and regular rains. But she is wishing she could get another month on either end of the growing season.

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What should you know before building a new greenhouse? Start by identifying your space, climate, and goals—whether it’s year-round food production, a plant haven, or a cozy garden retreat. Choose between freestanding or home-attached structures, and consider features like polycarbonate for insulation, drop doors for height, and automatic vents for heat control. From concrete foundations to seating areas and self-watering beds, thoughtful planning ensures your greenhouse meets your specific needs. Whether you're downsizing or adapting to a colder climate, the right design and features will transform your growing space into a functional and relaxing extension of your home.

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Building a New Greenhouse: Best Features and Design Ideas

What is the best feature of your existing greenhouse? And what would you change if you could do it all over again and build a new greenhouse from scratch?

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To stagger your harvest and maximize your greenhouse space, start cold-tolerant crops like cauliflower, broccoli, spinach, arugula, and green onions in mid to late summer, filling gaps as summer plants finish. This double-cropping method ensures a steady supply of fresh produce through fall and winter without needing supplemental heat. By seeding early, transplanting strategically, and using light frost protection like row covers, you can extend your growing season and enjoy bug-resistant, off-season harvests.

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The peak of summer brings the best of all worlds for the greenhouse gardener. Early tomatoes, the first zucchini and loads of strawberries. But there is another thing summer brings. The chance to start winter vegetables in your greenhouse.

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Why grow your own lettuce this season? Growing full-size head lettuce in your greenhouse garden brings unmatched freshness, variety, and taste compared to store-bought bagged greens. Head lettuces like romaine, butter, crisphead, and leaf types offer richer textures, better crunch, and longer shelf life. They’re ideal for salads, wraps, and sandwiches—and thrive in small spaces between larger greenhouse crops. With easy care, seed-saving potential, and improved nutrition from organic soil, homegrown lettuce is a flavorful, sustainable upgrade to your garden. Rediscover the joy of harvesting crisp, nutrient-packed greens right outside your door.

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If you watch old re-runs on Netflix you have seen how fashions and styles have changed dramatically since Seinfeld was filmed in the 1990s. The same is true for food – especially lettuce.

I first wrote about “novel” mesclun greens (mixed lettuce) in 1995. Since then, they have become so popular, that bagged lettuce is the only lettuce most people know. And this is too bad because lettuce greens or bagged greens are really just immature greens like kale and lettuce leaves. So, for something completely novel, why not go back to the future? Grow full-size head lettuce in your Greenhouse Garden this year.

Most people don’t remember life before the small bags of lettuce leaves so commonly sold now at big box stores and local farm markets. But if you want the crunch of lettuce in a BLT sandwich or if you want to replace Pita bread with a Keto-friendly lettuce leaf wrap for lunch, then start growing your own heads of lettuce this season.