12 Practical & Surprising Ways to Use a Greenhouse Year-Round

If a greenhouse is on your garden wish list, it’s helpful to know what to expect. In cold climates, unheated greenhouses have different uses at each time of year. Learn the pros and cons along with some surprising, alternate uses.

If you are interested in building your own, this shows how I built my lean-to greenhouse step-by-step.

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Greenhouse Pros and Cons

It is several years now since I built my lean-to greenhouse next to our house and, while I love it, there have been some surprises.

Let’s go over some expectations versus reality along with some unusual benefits.

Unrealistic Expectations

The biggest misconception I hear about home greenhouses—along with other season extenders like cold frames and polytunnels— is expecting them to maintain consistent, warm growing conditions year-round, even in a cold climate.

Some gardeners envision their new greenhouse will be like those at botanical gardens growing an array of fabulous tropical plants all year-round.

In reality, this type of greenhouse growing requires some combination of added lighting, heating, cooling, humidifiers, and watering systems—things we may not have the budget for at home.

Unheated greenhouses heat up in the day and cool down at night.
This can mean it’s too hot in the summer and too cold in the winter.

A basic, unheated greenhouse is really just a shell providing shelter from wind, rain, and snow.

Whether polycarbonate, glass, or polyethylene sheeting, any inherent insulating properties will be minimal.

They heat up by day and cool down by night. In winter, this can mean a lot of heat is trapped by day and lost at night—something few plants tolerate.

There are plenty of recommendations for trapping and retaining warmth to offset those cold nights, but, as-is, during certain times of year, an unheated greenhouse will not grow plants.

The amount of daylight hours each season will also significantly affect what can or cannot grow and when.

And, despite our wishes, a greenhouse is unlikely to be pest-free. Insects, mice, and other animals may still find their way in.

That’s an eyeopener for new greenhouse owners. Any visions of a glass house overflowing with flowers and vegetable crops as snow flakes gently fall outside is neither realistic nor practical.

But, if you’re adaptable, they can be a wonderful addition.

I’ll show you what I’ve added to my greenhouse since I first built it and then we’ll look at some unexpected other uses.

Accessories For Unheated Greenhouses

• A thermometer (with 24-hour memory listing max highs and lows). Get a Wi-fi thermometer if you want notifications when temperatures reach certain levels.
• UV-resistant shade cloths (to reduce the intensity of the light). They come in different strengths.
• An air vent (which I open and close manually). You can also use an automated vent arm that opens and closes at certain temperatures.
• Frost cloths to protect tender seedlings.

Nice to Have

• Rubber shelf liners to make it easy to clean up.
• Water outlet. My hose reaches the greenhouse so that’s fine too.

You’ll notice that I do not use any external heating or cooling devices. I just work with whatever the current season and conditions have to offer.

Traditional & Surprising Uses

While I wouldn’t say the cost of buying or building a greenhouse is warranted by any of these uses on their own, with so many options, even a small greenhouse can have lots of uses at any time of year.

Seed Starting

Let’s start with a popular use: seed starting. While I like to start a lot of seeds indoors in my home to get a jump start on the growing season, I’ve found sowing in my greenhouse works nicely too.

Indoors is more reliable for tender seeds but a greenhouse works nicely for hardier plants plus I don’t worry about any mess or spilled water.

I start sowing trays of seedlings in the greenhouse in late winter. Early on they need some protection like old blankets to insulate the trays and frost cloths over top at night.

As temperatures and light increase, the seedlings sprout and grow. Routine care includes watering and putting up sunshades on bright days.

You can also use a greenhouse to harden off young plants in preparation for transplanting outdoors.

Grow Fast-Growing Crops

The fastest growing food crops are cold-tolerant vegetables which we grow for their edible stems and leaves. Without the need to wait for flowering and fruit production, the quick growers can be harvested any time.

This makes them perfect for greenhouse growing in the moderate seasons.

The ideal soil temperature range (for soil) is 50 to 68 °F (10 to 20° C).

When I do my late winter seed starting, I always get a few containers of salad greens going in the greenhouse and sow more every few weeks for a continuous harvest. I like mesclun mix seeds for this.

Other options include microgreens, sunflower sprouts, arugula, pea shoots, and spinach.

I use frost cloths as needed to protect the seedlings as needed.

Overwinter Plants

If you grow tender annuals or perennials in pots, a greenhouse may be just the place to overwinter them. It’s perfect for plants like geraniums (Pelargoniums) and hardy fruit trees including Chicago figs.

If you’re letting the overwintered plant go dormant, you’ll want to cover it to block out light (while allowing air flow) and insulate the pot to prevent roots from freezing. I set a monthly reminder on my phone to check if they need watering.

Ripening Fruit

My little potted lemon tree has produced an abundance of lemons in my greenhouse. With sunshades up, the summer heat is favorable for ripening some tree fruits.

Dehydrate Food

From spring to fall, the intense light and heat within a greenhouse can be perfect for dehydrating fruits, vegetables, and herbs.

Thinly slice your items (mango and tomatoes are favorites here) and spread them out on lined trays.

While I wouldn’t want to leave things overnight when mice might be roaming about, a few sunny afternoons may be all it takes.

Dry Laundry

Greenhouses can make great clothes dryers! Instead of worrying about rain with an outdoor laundry line, I have lines and clothes pegs ready to go in the greenhouse.

It’s amazing how fast denim jeans will dry in the intense afternoon heat.

Warm Cats

I’m only half kidding! One of our cats (Clara) loves nothing more than an afternoon nap in the greenhouse. Unfortunately, she also finds laying on sprouting seedlings most comfortable. But any time the space is clear, it’s all hers.

Propagate Plant Cuttings

I mentioned how unheated greenhouses are often expected to work like temperature-controlled greenhouses at botanical gardens, and, of course, they don’t. While I don’t grow tropical plans ongoing in the greenhouse, spring and early fall are good times to propagate plant cuttings.

Use these step-by-step instructions for softwood cuttings in spring and hardwood cuttings in fall.

Other Greenhouse Uses

If you have room, here are some other uses to consider.

Work & Play

It’s not just a greenhouse, it’s a spare room. I’ve seen everything from greenhouses converted into bedrooms listed on Airbnb, for glamping, and use as party rentals. That’s one way to recoup your building costs.

For personal use, add the right furnishings and you’ve got a rec room, office, or art studio.

I’ve also seen greenhouses with hot tubs inside. With that much electricity use, it might be worthwhile to add solar panels to generate some of that power for you.

Aquaponics

It’s fairly common for greenhouses in our area to have space dedicated to raising fish with the waste water used to water plants.

Hatching Chickens

If the conditions are right and you have somewhere to plug in a heat lamp, your greenhouse may be just the place to incubate and hatch chicks.

So many of these ideas are not things you anticipate when getting a greenhouse, but the space can be useful for so many things beyond growing plants.

Resources

• How to Build a Lean-to Greenhouse (Step-by-Step)
• Greenhouse Kit (6×10 polycarbonate) | Amazon

~Melissa the Empress of Dirt ♛