Smart Tips for Building Your Own DIY Greenhouse

A greenhouse offers bountiful benefits: It extends your growing season, prevents pests from destroying your plants, reduces your grocery bill, and leads to healthier plants and a higher yield.

Keep reading for tips on how to build your very own DIY greenhouse.

Follow these general guidelines when building a backyard greenhouse:

Sun exposure is arguably the most important factor for your greenhouse. Pick a spot on the south side of your home that gets the most sunlight from fall through winter. If that’s not an option, your next best sites are the southeast or east sides, followed by the west or southwest. The least ideal location is the north side of your home. 

Depending on the types of plants you want to grow, your greenhouse may benefit from afternoon shade. Consider situating your greenhouse near deciduous trees—trees that shed their leaves seasonally. In the summer, these trees shelter your greenhouse from the hot sun. During winter, their leaves fall off and give your greenhouse the extra sunlight it needs.

A freestanding greenhouse gives you flexibility in terms of size, placement, and expandability. On the other hand, a greenhouse attached to your house requires fewer materials and provides easy access to your home’s heating, electricity, and water. 

You have the option to purchase a pre-made greenhouse kit, which includes all the necessary materials and instructions—and many of the components are pre-assembled. This is ideal for beginners or anyone in a time crunch.

However, crafting a greenhouse from the ground up gives you full control over the design, giving you the freedom to customize it to suit your specific needs. Keep in mind that this kind of undertaking requires a more advanced skill set and may take longer to complete.

DIY greenhouse projects can be as affordable or as expensive as you make them—it depends on the materials, size, and features you pick. For budget-friendly options, try upcycling old windows for the frame or roof or turning bookshelves into storage space. 

However, if you’re willing to invest, a high-end greenhouse with professional-grade materials and automated heating and ventilation systems makes less work for you and can increase your gardening success. 

When considering greenhouse sizes, a good rule to follow is one square foot of space for every six-inch pot. Also, make sure your structure is at least 25% larger than you think you’ll need because plant collections usually get bigger, not smaller.

You’ll also need to factor in pathway sizes. If you’re the only one using your greenhouse, allow at least 19 inches for your paths. If you’re bringing in visitors or equipment, plan for at least 24 inches of space.

Glass, polycarbonate, and acrylic are all great for crafting functional, durable, and beautiful greenhouses. Here’s a quick rundown of each material:

• Glass: Glass is the classic choice due to its sustainability and beauty. It also offers the best longevity with an average 25-year lifespan. However, it’s heavy and easily damaged by inclement weather.
• Polycarbonate: Polycarbonate is a lighter option with higher impact resistance than glass, but it has a lifespan of 7–12 years and will yellow over time due to UV exposure.
• Acrylic: Acrylic is a naturally UV-resistant material that provides the highest light transmission of all three. It won’t yellow over its average lifespan of 15–20 years. However, like glass, acrylic is susceptible to inclement weather and is more brittle than polycarbonate.

If you plan to grow plants in the winter, your greenhouse will need heat. Roughly 25% of your heat comes from the sun, so another heat source is required. Oil, gas, and electricity are common options delivered via forced air, steam, or radiant heating. For a more eco-friendly approach, try composting or passive solar energy.

In summer, proper ventilation is key to keeping your plants healthy. The easiest option is a fan, which should cycle the air about once per minute. For a high-end solution, consider automatic vent openers, which can regulate airflow with little to no effort on your part.

Once you have a plan in place for your greenhouse, take a moment to think about these factors:

• DIY or professional help: Do you want the satisfaction of building a greenhouse yourself, or would you rather play it safe and hire a contractor?
• Good drainage: Build your greenhouse on a level, well-drained surface. Avoid slopes where cold air collects, which increases the chances of frost.
• Storm damage: Position your greenhouse in a spot shielded from strong winds. For added protection, plant tall hedges or fencing around it.