What are Raised Garden Beds?
But let's start with a draft and a definition. When we say "raised garden bed" or simply "raised bed," we mean a freestanding box or frame—traditionally without a bottom or top—in a sunny spot filled with good quality soil. Raised beds are usually open at the bottom so that plant roots can access subsoil nutrients.
Of course, a raised bed can be simpler than that: You can build a raised bed without a frame by simply stacking the soil 6 to 8 inches high and leveling the top. This requires no additional materials (other than soil).
Benefits of Raised Garden Beds
There are many reasons for gardening in raised beds.
They drain well to help prevent erosion.
They heat up earlier in the spring, giving you a longer growing season because the soil above 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 from surrounding weeds and filled with disease-free and weed-free soil.
Since you're not walking on the bed, the soil doesn't compact and stays loose, eliminating the need for strenuous digging every spring. A loft bed helps keep everything organized.
Gardening is 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 great for small spaces where traditional row gardens might be too wild and bulky.
It is easier to separate and rotate crops each year.
Raised beds make square footage gardening and companion planting easier.
Depending on how tall you make it, a raised bed can even eliminate the need to bend over!
Finally, the loft bed is an attraction!
Choosing the Right Material for Your Loft Bed
You can choose to furnish your loft bed with whatever material you have on hand (wood, stone, brick, cement block). Stay away from painted or pressure-treated wood, which can leach chemicals or lead into the soil. The bricks can be placed end to end on the edge, or if you have enough bricks, they can be erected to create a higher edge for the bed.
Bury the bottoms a bit to stabilize them and keep weeds from slipping under and between the bricks. A few years ago I was lucky enough to acquire a large number of roof slates and used them to finish a raised bed on a slope. Cement blocks can be used to make beds for heat-loving plants. Here is a list of possibilities:
Untreated wood. Pine is the cheapest, but will rot after a few years, as will many untreated lumbers. Hemlock will last longer. Decay-resistant woods like cedar, redwood, or locust last longer; they are expensive. Cedar is preferred because it is both corrosion-resistant and durable and will last 10 to 15 years. It is also insect resistant thanks 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 choose thicker, untreated planks. For example, a 2-inch-thick larch plank can last ten years without treatment.
Modern treated wood contains chemicals that prevent decay. However, unlike in the past, 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 inside of the bed walls with polyethylene.
Railroad ties (treated) are easy because you just place them in the ground and nail them down. Old railroad ties treated with creosote don't seem to cause any health problems because 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 the chemical 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 "HT" or Heat Treated markings on pallets. Do not use pallets in your garden without a stamp or if you cannot verify the HT of the surface.
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 amend the soil.
Composite wood is a new product made from recycled plastic and wood fibers. It is corrosion resistant and durable, but also very expensive.
Cinder Block: The extra heat from concrete is perfect for Mediterranean-type herbs like rosemary and lavender. Their holes can be filled with soil mix and planted with herbs or strawberries. Each piece measures 16 inches long by 8 inches tall; best priced on larger cases.
Rocks and stones are abundant in some areas and can create nice free edges. You can build beds around the mound you've already started. Once closed, you can fill the sides with more soil and add compost, chopped leaves, manure, and more. Rake the top and let it sit until ready to plant next spring.
The two beds below were built using Trex lumber from 'second' piles from a local lumberyard. It's too twisty for building a deck, but works great for garden beds. The bottom is lined with a 1/4" stiff cloth screen to keep voles from eating the precious bulb.
How wide should a loft bed be?
Garden beds should be no more than 4 feet wide so you can enter the garden without stepping into the bed. Fortunately, lumber is usually cut in 4 foot increments.
Going to bed is taboo. It compacts the soil, making it harder for plant roots to get the oxygen they need. A bed that is too wide can also make 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 less than 4 feet (2 to 3 feet wide) because you can only access the garden from one side.
Length is not that important. You can make a 4x4 or 4x8 or 4x12 bed. Feel free to do whatever you want, but I find it easier to make a few short beds than one very long bed. Additionally, many crop families are best grown separately.
How deep should a loft bed be?
Typically, the standard size for wood, such as cedar, is 6 inches tall. In other words, it measures 2 inches x 6 inches x 8 feet. (Note that planks purchased at lumber yards are actually 1.5" thick x 5.5" high.)
You can of course go taller (18", 24", 36") but be aware that adding weight to the soil will increase the pressure on the sides. You'll need to add cross braces to any bed over 12 inches high. consider
what you might grow. The depth of the soil itself is very important, depending on how deep the crop needs in the ground. Examples: carrots, parsnips, potatoes, tomatoes, and
Root crops like squash need a soil depth of at least 12 to 18 inches. If the plant doesn't have loose soil this deep, the roots won't be able to penetrate deep enough for nutrients.
Shallow-rooted crops such as lettuce, vegetables, and onions require a soil depth of at least 6 inches.
To be safe, you only need to make sure the bed is 12 to 18 inches deep. Regardless of the height you choose for your frame, the soil beneath the ground will need to be loosened 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 only grow shallow-rooted crops.
loft bed location
Loft beds need to be in a sunny spot! Here are the requirements:
Most vegetables need 6 to 8 hours of direct sunlight ("full sun") each day, especially from lunchtime onwards.
Flat land, flat land.
Close to the house for easy weeding and harvesting
Do not place the bed in a windy location or in a frost bag.
The soil needs to drain well, so avoid any wet or swampy spots.
Preparing the Site: Option 1 (Basic)
To make a basic loft bed, use string to outline where you want it. 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, cut it short and dig it up, leaving the grass to one side.
Loosen the soil in the bed, turn the turf blocks upside down, scrape soil from the path outside and add it to the bed, along with any other amendments you wish to use to improve soil levels.
You can opt out here if you want.
Preparing the Site: Option 2 (No Excavation)
Some gardeners are too lazy to dig sod. Because as long as the layer is thick enough, the soil will block the grass and weeds below. Gardener Charles Dowding who created the "no digging" method. His philosophy is that digging brings more weed seeds to the soil surface, which leads to more weeds and more weeding. Digging also speeds up nutrient loss so you need to feed plants more often, and it tears apart the complex life and structure of the soil, reducing its ability to properly drain and hold water.
Here's how to build a raised bed using the "no digging" method:
Trim grass or weeds as close to the ground as possible. Then cover the area with cardboard, which will smother the grass/weeds and eventually rot into the soil. (Make sure you remove any tape and staples that won't
Make sure the cardboard/newspaper overlaps (about 6 inches) to ensure no weeds slip through the cracks. They'll reach out for any sunshine they can find.
Add a thick layer (4 to 6 inches) of compost on top of the cardboard. This will be your growing medium.
Once set up, you can get on the car and plant immediately. By the time the root reaches the cardboard, it has already begun 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. The beds need to be filled with fresh organic matter (an inch or two) every fall/winter, this will help to gradually improve the fertility and health of the soil, including the soil under the raised bed. That means you should do just fine with root vegetables like root crops.
