Building a loft bed is a great spring project. We'll help you get started with our step-by-step guide on how to build a simple loft bed from scratch. No special DIY skills required! Find out what wood or material to use, how big the bed should be, how to clear the site, and how to build the bed. Then, we discuss how to fill the raised bed and soil mix!
What is a raised garden bed?
But let's start with the scratch and the definitions. When we say "raised garden bed" or simply "raised bed" we mean a freestanding box or frame - traditionally without a bottom or top - that sits on the ground in a sunny spot and is filled with good quality soil. Raised beds are usually opened at the bottom so that plant roots can access soil nutrients below the ground.
Of course, a raised bed can be simpler than this: You can build a raised bed without a frame, just pile the soil 6 to 8 inches high and level the top. This requires no additional materials (other than soil).
Benefits of Raised Garden Beds
There are many reasons to garden on a raised bed.
They drain well and help prevent erosion.
They heat up early in the spring and give you a longer growing season because the soil above the ground heats up faster.
Raised beds allow you to control the soil you put in them, allowing for dense planting; plants that grow densely in raised beds mature faster.
They prevent weeds from taking over because the beds are lifted away from surrounding weeds and filled with disease- and weed-free soil.
Since you're not walking on the bed, the soil isn't compacted and stays loose, eliminating the need for painstaking digging every spring. Raised beds help keep things organized.
Garden chores become easier and more comfortable thanks to less bending and kneeling. Save your knees and back from the labor and pain of tending the garden!
Raised beds are perfect for small spaces where a traditional row garden might be too wild and unwieldy.
It is easier to separate and rotate crops each year.
Raised beds make square foot gardening and companion planting easier.
Choosing the Right Material for Your Raised Bed
You can choose to decorate your loft bed with whatever material you have on hand (wood, stone, brick, cement blocks). Stay away from painted or pressure-treated wood that can leach chemicals or lead into the soil. Bricks can be placed end to end on the edge, or if you have enough bricks, stand them up to make higher sides for the bed.
Bury the bottom a bit to stabilize them and prevent weeds from slipping under and between the bricks. A few years ago, I was lucky enough to get plenty of roof slates and used them to trim raised beds on slopes. Cement blocks can be used to make beds for heat-loving plants. Here is the list of possibilities:
untreated wood. Pine is the cheapest, but will rot after a few years, as will many untreated woods. Hemlock will last longer. Decay-resistant woods such as cedar, redwood, or locust will last longer; they are expensive. Cedar is preferred because it is both rot-resistant and durable, and will last 10 to 15 years. It is also insect resistant due to the oils in the wood. Reclaimed wood made from plastic bottles is also a bit more expensive, but lasts indefinitely. Another option is to simply opt for thicker, untreated planks. For example, a 2-inch thick larch plank will last ten years without treatment.
Modern treated wood contains chemicals that prevent rot. Unlike in the past, however, studies have shown that any leached compounds are within safe levels set by the EPA. Some gardeners are still uncomfortable with treated wood. For those concerned, one option is to line the interior of the bed wall with polyethylene.
Railroad sleepers (treated) are easy because you can simply place them on the ground and drive them with nails. Old railway sleepers treated with creosote don't seem to cause any health problems since most of the creosote has been lost.
Pallets can be an inexpensive source of garden bed material, as long as you know where they come from. Pallets were developed for transporting materials. Avoid trays that have also been treated with methyl bromide, a known endocrine disrupting chemical that can affect your reproductive health. Most pallet manufacturers stopped using the chemical in 2005, but many old pallets still exist. Look for the "HT" or heat treated stamp on the pallet. If there is no stamp or you cannot verify the HT on the surface, please do not use the tray in your garden.
Concrete or brick can be used. However, keep in mind that concrete will increase the pH of the soil over time and you may need to modify the soil.
Composite wood is a new product made from recycled plastic and wood fibers. It's rot-resistant and long-lasting, but it's also very expensive.
Cinder blocks: The extra heat collected from concrete is great for Mediterranean-type herbs like rosemary and lavender. Their holes can be filled with soil mix and planted with herbs or strawberries. Each piece is 16 inches long and 8 inches high; the big box prices are the most reasonable.
Rocks and stones are plentiful in some areas and make for nice free edges. You can build beds around mounds that you have already started. Once it's closed, you can fill the sides with more soil and add compost, chopped leaves, fertilizer, etc. Rake the top flat and let it sit until next spring to be ready to plant.
The two beds below were built using Trex lumber from "seconds" piles from a local lumber yard. It's too twisty for building decks, but works well for garden beds. The bottom is lined with a 1/4-inch hard cloth screen to keep the voles from eating the precious bulbs.
How wide should your loft bed be?
Garden beds should be no wider than 4 feet so that you can enter the garden without stepping into the bed. Fortunately, wood is usually cut in 4-foot increments.
Stepping into bed is a no-no. It compacts the soil, making it harder for plant roots to get the oxygen they need. Making the bed too wide also makes the middle difficult to reach, which also makes weeding and harvesting difficult.
If your raised bed is built against a wall or fence, we recommend setting it to less than 4 feet (2 to 3 feet wide) as you can only access the garden from one side.
Length is not so important. You can make 4x4 or 4x8 or 4x12 beds. Feel free to do whatever you want, but I find it easier to make a few shorter beds than a very long one. Also, many crop families are best separated into beds.
How deep should a loft bed be?
Typically, the standard size for wood, such as cedar, is 6 inches tall. In other words, the dimensions are 2 inches x 6 inches x 8 feet. (Note that planks purchased at the lumber yard are actually 1.5" thick x 5.5" high.)
You can also stack the two boards. The height of the two stacked "2x6" boards is 12" (technically 11").
You can certainly go higher (18", 24", 36"), but be aware that adding the weight of soil will increase the pressure on the sides. You will need to add cross bracing to any bed over 12 inches tall.
Consider what you might grow. The depth of the soil itself is very important and depends on how much soil depth the crop needs in the ground. E.g:
Rooted crops such as carrots, parsnips, potatoes, tomatoes, and squash require a soil depth of at least 12 to 18 inches. If the plant doesn't have this deep loose soil, the roots won't be able to penetrate deep enough for nutrients.
Shallow root crops (such as lettuce, vegetables, and onions) require a soil depth of at least 6 inches.
To be on the safe side, you just need to make sure the bed is 12 to 18 inches deep. No matter what height you choose for your frame, you will need to loosen the soil below the ground accordingly. For example, if you have a 6-inch high bed, we recommend loosening the soil in the ground an additional 6 to 9 inches if you want to grow root vegetables. This is not necessary if you are only growing shallow root crops.
loft bed location
The loft bed needs to be in a sunny location! Here are the requirements:
Most vegetables need 6 to 8 hours of direct sunlight ("full sun") a day, especially from lunchtime.
Level, level ground.
Proximity to house for easy weeding and harvesting
Do not place the bed in a windy place or in a frost bag.
The soil needs to be well drained, so avoid any wet or swampy areas.
Prepare the venue: Option 1 (Basic)
To make a basic loft bed, use string to outline where you want it to be. As above, keep it between 3 and 4 feet wide so you can still easily reach the center.
This will help smother the grass in the area, but if there is sod or grass, trim it short and dig it out, saving the clumps to one side.
Loosen the soil on the bed, turn the turf clumps upside down, scrape the soil from the outside path and add it to the bed, as well as any other amendments you wish to use to raise the soil level.
You can log out here if you want.
Preparing the site: Option 2 (no excavation)
Some gardeners don't bother to dig sod. Because as long as one layer is thick enough, the soil will block the grass and weeds below. Gardener Charles Dawding, who created the "no dig" method. His philosophy is that digging brings more weed seeds to the soil surface, which leads to more weeds and more weeding. Digging also accelerates nutrient loss, so you need to feed your plants more often, and it rips apart the complex life and very structure of the soil, reducing its ability to drain and hold water properly.
Here's how to build a raised bed using the "no-dig" method:
Trim grass or weeds as close to the ground as possible. Then cover the area with cardboard, which can smother the grass/weeds and eventually rot into the soil. (Make sure you remove any tape and staples that won't break down.)
Make sure to overlap the cardboard/newspaper (about 6 inches) to make sure no weeds slip through the cracks. They'll reach for any sunlight they can find.
Add a thick layer of compost (4 to 6 inches) on top of the cardboard. This will be your growth medium.
After setting it up, you can immediately get on the car and plant it. By the time the root reaches the cardboard, it has already started to break down and the root will be able to search deeper beyond the cardboard layers.
The compost you add on top should gradually combine with the soil below, through the action of worms etc. Each fall/winter, the beds need to be filled with fresh organic matter (an inch or two), which will help gradually improve the fertility and health of the soil, including below the raised bed. This means you should be doing well with rooted vegetables like root crops.
For those with compacted or bad soil
In soils that have been damaged by compaction or have other problems, digging in the ground is often required, but only once. This is most important for deeply rooted crops, such as carrots, because they do better in soil that has been loosened and corrected to 10 to 12 inches to allow air and water to enter the plant's roots.
After cutting the grass short and digging it out, remove the top layer (about a shovel's depth or 10 inches); it's probably easiest to work in rows.
Remove all rocks, old roots and plant debris.
Use the shovel to dig a little more (a few more inches) to loosen the soil.
Mix the soil with organic matter such as compost. We recommend composting to 25% of the soil.
Then go back to the top layer and mix the soil layers together.
How to Build Your Garden Bed!
Let's make the bed! You're just building a box - like a sandbox - so it requires minimal DIY skills. Buying commercially grown garden kits is fine, but their prices can be daunting.
tool
Drills/Screwdrivers and Bits, Screwdrivers
If you cut the boards yourself (compared to a lumber shop): hand saw, tape measure
Material
For a 4x8ft bed, prepare 3 8ft pieces of 2"x6" lumber. Even better if they have 2"x8" or 2"x10" lumber. For a 4x4 bed, get 2 pieces of wood.
If you don't have a saw, have someone at the lumber mill cut the pieces in half. For a 4x8 foot bed, cut one of the pieces in half, giving you two 4 foot lengths for the ends. For a 4x4 bed, cut the two parts in half.
Deck/Exterior Screws
To make it stronger, use a piece of 2X4 or 4X4 in the corners to give you some stabilizing nails or screws instead of the end texture of the board.
make bedside
If your two 8-foot boards were not pre-cut at the lumber store, mark the mid-point and cut each board in half to get a 4-foot-by-4-foot bed. Then you will have four planks.
You will use decorative screws to screw the boards together. Two holes at the end of each plank should suffice. Use a drill bit thinner than the screw itself to drill the pilot hole. One end of each plank will overlap and screw directly into one end of the next plank, so position the pilot holes accordingly. It will be easier if you have an assistant to hold it while you fix the corners.
If you want extra support and a stronger frame, cut your pine stakes into four pieces and use them to nail planks in the corners for support.
Assembling the loft bed
Once all the wood is cut to size and drilled, we can start assembling the bed.
Put down the bed. The walls need to be laid out so that each plank overlaps the next, with the pilot holes at the overlapping ends.
Screw the walls together with long screws so that each wall may be fastened to the next
We want a comfortable, snug fit.
Padded loft bed
The most important part of any garden is the soil, and the more organic matter it has, the better. Soil microbes are fed, and oxygen and water easily reach the roots, so plants thrive. Here's the balance to strike:
40% Compost: Compost is rich in plant nutrients. While you can compost at home, you can also buy bagged fertilizer from your local garden center. Aged fertilizer can also be used, but fresh fertilizer cannot be placed directly in the garden. Learn more about fertilizers.
40% Topsoil: In terms of topsoil, we're not talking about "potting soil" because it's too loose for a raised bed. You can also find bagged topsoil at a garden center or local farm supply or lumber store.
20% Aeration: In terms of aeration, many bagged soil mixes already contain some perlite, pumice, or rice husks. If not, you'll need to add something to drain. Lava is also a good aerator for drainage.
If you're filling a lot of raised beds, we recommend finding a local landscape company to build a soil and compost mix, which should be less expensive. However, if you're just filling up a small bed, bags are your best option.
There are two methods of packing a bed:
Some people pour in compost (or compost manure) first, then add topsoil (as shown in the video above).
Others add toppings in layers like lasagna, stirring as they go.
Do whatever is easier for you!
At the end of the growing season, in the fall or winter, top up your raised bed with more compost. It will improve fertility as it enters the soil and will be planted in spring.
Raised Garden Bed Soil Mix
This is the best formula we've developed over the past decade for our garden beds.
A 4x4 foot loft bed. (Multiply by filling a larger bed.)
4 cubic feet of topsoil
3 cubic feet of coconut palm (Note: Peat moss has traditionally been used as part of garden soils, but since it is not a sustainable material, we recommend using coconut palm instead.)
2 to 3 cubic feet of compost or compost
2-inch layer of crushed leaves or grass clippings.
If you use grass clippings, make sure they're not from lawns that have been sprayed with herbicides or fertilized with foods that contain granular herbicides to kill weeds. Both persist and kill plants within three years of initial application.
Mix all materials with a hoe or cultivator and water. Be sure to mulch well with organic matter, such as more leaves or clippings or straw.
In the first year, you probably won't need much to add plant fertilizer or reduce fertilizer usage. But over the next few years, as your food crops absorb all the nutrients, your soil will need some improvement with a balanced slow-release fertilizer (or more compost). Find out how and when to fertilize your garden.
After planting, you'll want to spread some mulch (leaves, straw, pine needles, or more compost) over the bed to retain moisture and suppress weeds. Read all about coverage here.
What to Plant in Raised Beds
If you're a beginner gardener, we recommend you start with a raised bed and try growing some of your favorite vegetables. Ultimately, four or five raised beds are grouped together to form a decent-sized garden.
What you plant is only limited by the depth of the soil—this is the depth of your raised bed plus the depth of the soil you dug and loosened in the ground.
What grows well in 6 inches of soil:
Lettuce, salad greens, spinach, onions, leeks, radishes, strawberries, basil, chives, cilantro, dill, mint, oregano, parsley, thyme, marigolds, and other annual flowers
What grows well in 12 inches of soil depth:
beans, beets, broccoli, Brussels sprouts, cabbage, cantaloupe, carrots, cauliflower, kale, cucumber, garlic, kale, zucchini, Swiss chard, radishes, lavender, rosemary, sage, borage, Calendula, cosmos, lantana, nasturtium, snapdragon, fragrant snowball (plus everything on the 6" list)
What grows well in 18 inches of soil depth:
eggplant, okra, peppers, squash, sweet potatoes, tomatoes, watermelon and winter squash (plus everything on the 6" and 12" lists)
If you're a beginner gardener, we recommend you start with a raised bed and try growing some of your favorite vegetables. Ultimately, four or five raised beds are grouped together to form a decent-sized garden.
What you plant is only limited by the depth of the soil—this is the depth of your raised bed plus the depth of the soil you dug and loosened in the ground.
What grows well in 6 inches of soil:
Lettuce, salad greens, spinach, onions, leeks, radishes, strawberries, basil, chives, cilantro, dill, mint, oregano, parsley, thyme, marigolds, and other annual flowers
What grows well in 12 inches of soil depth:
beans, beets, broccoli, Brussels sprouts, cabbage, cantaloupe, carrots, cauliflower, kale, cucumber, garlic, kale, zucchini, Swiss chard, radishes, lavender, rosemary, sage, borage, Calendula, cosmos, lantana, nasturtium, snapdragon, fragrant snowball (plus everything on the 6" list)
What grows well in 18 inches of soil depth:
Eggplant, okra, peppers, squash, sweet potatoes, tomatoes, watermelon and winter squash (plus everything on the 6" and 12" lists)
For ideas, we have some sample rack bed vegetable garden plans - with plant lists!
Also, note that many vegetables grow best from seed, but some do better as young starter plants (especially tomatoes and peppers). See how to start a seed or plant.
Once you've built your raised bed and filled it with soil and compost, you're ready to start planting and growing your garden!
Here's a handy tool: The Old Farmer's Almanac Garden Planner! In minutes, you can create a garden plan on your computer. GardenPlanner will show you how many crops fit in each space so you don't overbuy or waste seeds. Test our Garden Planner with a 7-day free trial - plenty of time to play and plan your first garden!
