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Gardening in Winter using Raised Beds in a Greenhouse

gardening in winter using raised beds in a greenhouse

While talking with a friend the other day, they asked why I wasn’t using raised beds in my greenhouse. After talking about it for a while and doing my own research, I quickly decided to build some raised beds for my greenhouse before spring began.

For a greenhouse in winter, raised beds extend your growing season, since the soil warms earlier. Raised beds also provide easier pest control, help organize your garden & create paths, & prevent the need for tilling the soil. However, you can also consider shelves instead of raised beds.

Not to mention the fact that raised beds will do wonders for your back, as you'll be stooping and bending much less!
gardening in winter using raised beds in a greenhouse

What are the advantages of raised beds?

Now that we know what a raised bed is, what are the advantages? For one thing, they will organize your garden with ease.

Imagine never again wondering if your sprouts are zucchini or watermelon, because you’ve planted your zucchini in the raised bed in the left of your greenhouse, and your watermelons in the raised bed on the right of your greenhouse.

Due to the boxy nature of the raised beds, they’ll naturally create pathways in your greenhouse. Any gardener will tell you about how frustrating it is to have a gardening work-space that involves constantly tiptoeing and maneuvering around their crops.

Due to the boxes being elevated, they’ll keep the weeds that grow along your pathways out of your boxes, making it easier to mitigate the annoying weeds that sprout in your garden.

This same principle, then, would apply to annoying garden pests like slugs.

There’s also the point of drainage. Using elevated beds will result in improved drainage for your garden, as the raised beds will use gravity to drain.

Depending on where you live and what you’re gardening on, this may or may not have been a problem in the past for you. By using raised beds, you won’t have water pooling up on compacted soil below your roots. 

The last and perhaps most important advantage to gardening with raised beds is the favors you will do for your back. As you build or buy your box, it’s important to keep in mind how you’d like to be working in your garden. Ideally, raised beds will make it so that you stoop and bend far less often when gardening.

Depending on the height of the box, you can create comfortable gardening space where your crops sit waist high, meaning they would be level with you when kneeling. If you create your box to be even taller, you can make it so that it’s at a perfect level to work on while standing.

Why would I want to use a raised bed in the winter?

Arguably, the biggest advantage to using raised beds in your garden is that it increases your growing season. The soil in your raised beds will thaw much quicker than the ground. With any luck, the soil in your raised beds won’t be frozen during winter at all.

Due to the raised beds not sharing soil with the ground, the soil in the beds will warm much earlier in the spring, allowing for you to get an earlier, more advantageous head start on your gardening season.

Depending on where you live, it’s completely possible to combine the advantages of raised beds and greenhouses to create a situation where you can garden all year long.

Granted, this may not be possible in, say, the Rocky Mountains, but in warmer, southern climates, it’s completely possible to be growing produce all year long! The trick is to know the incoming weather and mitigate your greenhouse and raised beds temperatures so that nothing freezes.

The disadvantages of using raised beds in a greenhouse

It is worth noting that gardening with raised beds in a greenhouse is much different than gardening outside in raised beds.  It’s also worth noting that, although gardening with raised beds in a greenhouse has many advantages, it also has a few disadvantages as well.

While we already know that raised bed gardening presents all the advantages mentioned above, there are still some downsides to using raised beds in your garden.

Perhaps the biggest disadvantage of using raised beds in your greenhouse is that once they’re set up, they are extremely difficult to move around or disassemble.

Think about it: building a raised bed with all sorts of heavy wood or materials, and then filling it with soil can create a lot of weight.

If you’re going to use raised beds in your greenhouse or garden, it’s important to think hard about the layout that you want the boxes to be in.

Then, there’s the price factor. Another big disadvantage of raised beds is that they can be expensive to buy/build. Sure, once you have one, it probably won’t require further expense. However, the initial price to get you started may be a little steep.

Why use raised beds instead of shelves?

You may be asking, well why not just use shelving instead of raised beds? Shelving, after all, would be much cheaper and much more mobile than raised beds, right?

There are, primarily, two main reasons to use a raised bed over shelving. The first being that, by spreading out your crops over a horizontal surface, they all stand to absorb the same amount of sunlight.

If you are growing crops on shelves, you will constantly be shuffling different plants so that some are on the top shelf somedays and other crops are on the top shelves on other days.

While light in a greenhouse is typically pretty distributed, there’s no denying that a plant on the bottom shelf won’t get as much sunlight as its top-shelf counterparts.

The Temporary Greenhouse AKA Hoop Houses

There is the option of constructing a raised bed, and creating a temporary greenhouse around it to provide warmth during colder times.

One of these easiest ways to create a temporary greenhouse is to make a hoop house. A hoop house is usually a structure that you place around your greenhouse that is wrapped with plastic or an insulator when it’s cold.

Then when the weather warms up, the plastic is typically removed to expose the garden to the outside.

Hoop houses can be constructed rather cheaply using stakes, long PVC pipes and some plastic sheeting.

Simply drive stakes along either side of your raised bed, bend the PVC pipes over the raised bed and insert both ends into the stakes, and then cover and secure the plastic sheets to the PVC pipes.

making a raised bed


Making a raised bed

Raised beds don’t have to be bought, however. Using wood or stone, a person could make their own raised beds! A huge advantage to this is that homemade raised beds are oftentimes much cheaper than buying one.

When you think about actually making a raised bed, the idea may be harder than the actual action. Simply nail wood together to create a rectangle! However, there are a couple of questions to ask yourself as you begin to construct your raised bed.

The first question to ask yourself is “How deep do I want my raised bed to be?” Typically, six inches is the bare minimum depth to allow your crops to have good root growth.

However, 12 inches deep would allow much better root growth for a variety of plants. For this reason, you should plan on making your raised bed at least a foot deep.

You can line your bed with several different materials in order to allow for more insulation, or to prevent pests from getting into your raised bed.

If you don’t want your plants’ roots growing into the soil below your raised bed, you may have to line the floor of the bed with a solid material.

A really easy liner to use is landscape fabric. Landscape fabric is better than, say plastic, as plastic won’t allow for easy water drainage. If you’re worried about rodents burrowing into your raised bed, you can also line the bottom of your bed with mesh designed to keep out those rodents.

The materials that you use depend on a plethora of different variables, including things like toxicity, cost, and aesthetics. For example, using a material such as plastic lumber may look extremely nice, it can be costly and call also be toxic to your soils and plants.

Conversely, recycled materials such as urbanite may be much cheaper and have a lower environmental impact, but it also may not create an aesthetic look in your garden.

Before building a raised bed, consider your budget and what you’d like to the raised bed to look like, and then choose the materials for a raised bed.

Planting in Raised Beds

So what do we plant in our raised beds? The short answer is: whatever you want! However, if you’ve constructed raised beds to garden in the winter, there are several crops that grow much easier in winter months than others.

Plants that grow well in colder conditions include vegetables such as onions, peas, spinach, kale, broad beans and Brussels sprouts.

How far apart you plant your crops really depends on what you’re growing. For instance, heads of lettuce should be roughly a foot apart. Carrots, on the other hand, only need to be plants two or three inches apart from one another.

Research what you plan to grow and see how far apart you should space your seeds. Regardless of what you grow, plant your crops in a grid pattern across the bed, utilizing all of the space that you’ve given yourself.

Depending on the climate in which you live, it may be best to sprout seeds in your house or warmer climate before transplanting them to your raised bed in your greenhouse.

Keeping a raised bed warm

There are several ways to keep your raised bed warm in the winter months. Methods include not using mulch, using landscape fabric or another material and using soil warmers.

Due to mulch typically being used to keep soils cool, it may be best to not use mulch at all during the winter months. If you’re worried about keeping soil as warm as possible, till up the soil about one or two inches deep to allow it to dry and warm faster.

Another method is to use the liners mentioned previously. Landscape fabric can be used to help insulate your raised bed and keep your soil from touching the cold ground.

The heavier the material, the warmer it will keep your raised bed. However, keep in mind that the heavier the material (like a plastic), the more difficult it will be for your raised be to drain.

Another great method to keep your soil warm is through using soil warmers. Typically run off of electricity, soil warmers are tools that are heated in the ground to keep your raised bed warm.

To wrap up

Raised beds offer a gardener so much more control over how their garden is operated, and I’m a little disappointed I wasn’t using them sooner. Almost all the things that make it very difficult to garden in the wintertime can be fixed using raised beds.

keeping a raised bed warm


Related Questions: 

How do you keep a greenhouse warm?

Besides obvious methods like using a heater, perhaps the easiest way to keep a greenhouse warm is to use insulation that allows for heat to remain in your greenhouse longer. Plastic covers over your raised beds are an excellent insulator to add.

How do I protect potted plants in the winter?

There are several ways to help insulate potted plants in the winter. More soil will be an excellent insulator. In addition to this, you can encircle your pots with a blanket, towel or mulch to help insulate your potted plants.

What vegetables should be planted together in a raised bed?

Many vegetables can benefit off of being planted together. Known as Companion planting, certain plants pair well when being grown together. Vegetable duos include tomatoes and basil, corn and greenbeans or onions and carrots.

About the author

Greg Volente

Greg Volente holds a Naturalist Certificate from the Morton Arboretum, and worked for The Nature Conservancy leading environmental education programs and doing natural areas restoration. Besides gardening, he's an avid wildflower enthusiast, and loves botanizing, hiking, and backpacking.