Extend Your Growing Season — Prepare Your Greenhouse for Winter

September is the perfect time to start thinking ahead. The days are getting shorter, the nights are getting cooler, and gardens across Illinois are beginning to slow down. But if you have a greenhouse, your gardening season doesn’t have to end when the first frost arrives.

A greenhouse can give you extra weeks—or even months—to enjoy fresh herbs, greens, and other cool-weather plants. September is a great time to clean things up, start new plantings, and prepare your greenhouse for colder weather.

🌿 Plant Now for Fresh Herbs This Fall & Winter

One of my favorite things to grow in a greenhouse is fresh herbs. There’s just something about walking out to the greenhouse and clipping exactly what you need for dinner.

September is a good time to plant or move herbs into your greenhouse before temperatures begin dropping.

Some great choices include:

• Parsley – Hardy and useful in soups, sauces, potatoes, and casseroles.

• Chives – Easy to grow and great for eggs, baked potatoes, soups, and dips.

• Thyme – Loves well-drained soil and is wonderful with roasted vegetables and meats.

• Oregano – A must-have for homemade pizza, pasta sauces, and Italian dishes.

• Mint – Great for tea and drinks, but keep it in a container because it likes to spread!

• Rosemary – A favorite for breads, chicken, potatoes, and winter comfort foods.

• Cilantro – Prefers cooler temperatures, making fall a great time to grow it.

• Basil – Loves warmth, so enjoy it while your greenhouse temperatures remain warm enough.

Imagine heading into your greenhouse on a chilly fall evening and cutting fresh rosemary and thyme for dinner. That’s one of the little pleasures a greenhouse can bring to your backyard.

🥬 Don’t Stop With Herbs

Herbs aren’t the only things you can grow as temperatures cool.

Consider planting lettuce, spinach, kale, arugula, radishes, green onions, and other cool-season crops. Depending on your greenhouse setup and whether you add supplemental heat, you may be able to keep harvesting well beyond your normal outdoor gardening season.

September is the time to get those plants established while there is still plenty of daylight.

🍂 Prepare Your Greenhouse for Winter

Fall is also a good time to give your greenhouse a little attention.

Clean out old or unhealthy plants, remove weeds and debris, wash pots and trays before reusing them, and check around windows, doors, roof panels, and vents. Make sure everything is ready before cold winds and freezing temperatures arrive.

If you plan to garden throughout the winter, start thinking about heat, ventilation, lighting, and water now rather than waiting for the first freezing night.

Remember that a greenhouse captures heat from the sun, but an unheated greenhouse can still reach freezing temperatures during an Illinois winter. Tender plants and warm-season herbs may need additional protection or supplemental heat.

🌱 Bring the Garden Inside

If you already have herbs growing outside in containers, September is also a great time to decide which ones you want to bring into the greenhouse.

Inspect them carefully for insects before moving them inside. A few unwanted pests can quickly become a bigger problem in the protected greenhouse environment.

You can also take cuttings or divide certain established herbs instead of moving the entire plant.

🏡 A Greenhouse Can Be More Than a Spring Project

We often think about greenhouses in the spring when everyone is excited to start seeds. But fall may be when you really begin to appreciate having one.

It gives you a protected place to garden when the weather turns unpredictable, somewhere to keep your gardening supplies organized, and a place where you can still enjoy a little green when everything outside starts turning brown.

Fresh herbs. Fall greens. A longer growing season. And a warm, sunny place to spend a cool September afternoon.

That sounds pretty good to me.

Thinking About Adding a Greenhouse?

At Boondocks Barns, we can help you explore greenhouse and combination-building options that give you room for both gardening and storage.

Built to Last — Starting From the Ground Up.

Boondocks BarnsQuality • Value • Personal ServiceServing all of Illinois

🌿 Get Growing — Become a Better Herb Gardener!

Ready to grow fresh, flavorful herbs right at home? Download our FREE “Get Growing” Herb Gardening E-Book for simple tips to help you plant, grow, harvest, and enjoy your own herbs.

Whether you’re growing in a greenhouse, garden bed, or containers, this guide will help you get growing with confidence.

🌱 Download your FREE guide and start growing!