What NOT to Grow in Your Greenhouse: Common Mistakes to Avoid

Greenhouses are havens for gardeners, offering controlled environments that extend growing seasons and protect delicate plants from harsh weather. Yet, as any experienced gardener knows, not every plant thrives in these enclosed spaces. Avoiding common mistakes can save time, effort, and disappointment. Here’s a guide on what not to grow in your greenhouse:

Greenhouses have limited space, and large trees or shrubs quickly outgrow their containers. Their expansive root systems can damage greenhouse structures and overshadow smaller plants, limiting light and airflow. Reserve your greenhouse for plants that stay compact or are easily pruned.

Some plants, like mint or certain ivy species, are notorious for their aggressive growth. Once established in a greenhouse, they can quickly overtake other plants and become difficult to eradicate. Keep invasive species outside where their growth can be more easily controlled.

Annuals that thrive in short, intense outdoor growing seasons may struggle in a greenhouse. They require specific conditions, such as cooler nighttime temperatures or natural light variations, that are difficult to replicate indoors. It's often more efficient to grow these plants outdoors where they naturally flourish.

While some greenhouse crops can self-pollinate or rely on wind, many fruits and vegetables require pollinators like bees or butterflies to produce fruit. In a closed greenhouse environment, natural pollination can be limited or absent, resulting in poor yields. Unless you’re prepared to hand-pollinate, it’s best to grow these crops outdoors.

Greenhouses can create humid environments, but excessive moisture without adequate drainage promotes fungal diseases and root rot. Avoid plants that require consistently wet conditions unless your greenhouse setup includes excellent drainage and ventilation.

Certain tropical plants or heat-loving vegetables may struggle in a greenhouse during cooler months or in climates where winters are cold. Greenhouses can retain heat, but maintaining consistently high temperatures can be challenging and costly. Consider alternative heat sources or grow these plants in warmer outdoor conditions.

While some perennial plants thrive in containers, others need deep, extensive root systems or specific soil conditions that are difficult to replicate in pots. Research the specific needs of perennial plants before attempting to grow them long-term in a greenhouse setting.

Greenhouses provide protection from many pests and diseases, but they can also create ideal conditions for certain problems to flourish. Avoid plants with known susceptibility to common greenhouse pests and diseases unless you are equipped to monitor and manage these issues effectively.

Understanding what not to grow in your greenhouse is just as important as knowing what thrives in it. By avoiding these common pitfalls, you can make the most of your greenhouse space, maximize your yields, and create an environment where plants flourish. Focus on plants that benefit most from the controlled conditions and protection that your greenhouse provides, and enjoy a successful and productive gardening experience.

Happy gardening!