Raised Beds on the Patio Garden
Why use Raised Beds?
Creating raised beds around an outdoors patio garden may seem like more trouble than it’s worth. After all, you can use small containers, trellises and so many other forms of gardening on a patio. But raised beds can reward your time and effort with better drainage, easier growing, better harvesting and most of all convenience for many gardeners.
Raised beds are especially popular with gardeners who have knee or back problems, or who are elderly or disabled. They make a good companion to existing container gardens on a patio, as they have similar watering and fertilizing needs.
Since you’ll have complete control over the soil that goes into the beds, you also can be sure it is free of rocks, well-mixed, and rich with organic matter. Raised beds provide a structural limitation to weeds and pests, and allow plants to root deeply for better growth and health. They are ideal for patio gardeners, as they create a little garden directly on the patio where you can grow just about anything you want.
Types of Raised Beds
Raised beds can be placed in a number of locations, whether it is in a rooftop patio garden, just off your ground-level patio, or even on top of rock or concrete. Consider what type of raised bed will work best for your patio garden before beginning.
Here are some raised bed ideas:
If you are simply planting a variety of herbs for a little kitchen garden on your patio, choose half-barrel planters used in landscaping to give the herbs vertical drainage yet limited surface area, as several herbs can be invasive and should be given limited space. Walled raised beds will be the most common for patio gardeners, as they are quite versatile and can be built out of a variety of materials to match your patio or home.
Building a Raised Bed Garden
Make sure when planning your raised beds that they will be made of a non-toxic material that won’t leach chemicals into your plants’ roots. Stone, cinder blocks or bricks are common raised bed materials, and untreated lumber is another choice for those who are handy with carpentry. All of these should be available at garden or home improvement stores, and the stone and brick options come in a variety of shapes and colors for gardeners who want to have their beds match their patio or outdoor furniture.
Be sure if you are using lumber that you secure the corners of the boards well with braces, screws or reinforced blocks. There also are raised bed kits or snap-together frames available, which sometimes have the benefit of being easily taken apart for movement or storage. A popular material for raised beds in backyard gardens is old railroad ties, but these may be too large for use on a patio. However, most lumber and home improvement stores sell cut lumber in nice four-foot and smaller lengths, making it easy to replicate this look on your patio.
Designing a Raised Bed Garden on the Patio
Most raised beds should be between one and two feet high, but make them a height that you will find easy to work with, so that you don’t have to bend or kneel as much. As for width, if the bed is accessible from both sides, you can make them as wide as four feet, assuming you can reach two feet in from each side. If they are only reachable on one side, don’t make them much wider than two feet, as it will become difficult to reach in and tend the farthest plants. Rectangular shapes are the easiest to build, but you may choose other shapes based on your patio design and DIY capabilities.
Note that the location should be well leveled first so that the bed isn’t deeper on one side than the other. Check it with a level first to be sure all the water won’t drain to one side. Many gardeners also prefer to line the bottom of raised beds with black plastic or landscaping cloth to keep weeds from growing up through the bottom of the bed. If your bed is taller than about two feet, you will want to provide more support for the walls.
When using wood, you can drill holes vertically down through the wall, and insert stakes, rebar or other sturdy supports to keep the walls standing straight and even over time. When using brick or stone, be sure to mortar uneven stones and set uniform blocks offset from one row to the next, for better stability.
Placement of Your Raised Bed Patio Garden
Of course, you’ll want to place your raised beds in an attractive location around your patio, not just haphazardly. But while you’re considering placement, also choose a sunny location. Most plants will benefit from full sun, and will need it to produce their full potential at harvesting time. For maximum landscaping effect, try creating different heights, sizes and shapes of beds. You could, for instance, create a low, border-style bed to the outside of your taller main bed. Or, plan on growing your flowers in one raised bed as a focal point to draw the eye, and allowing smaller surrounding beds to grow vegetables and herbs.
Try to place plants you know will grow taller to the middle of the bed, and low, ground-level plants on the outsides, for ease of watering and tending throughout the season. One no-no for raised beds on your patio, however, is to build them right up against the house or shed. This will attract moisture– and eventually rot –to the side of the building, and shade the bed more than is healthy for most plants.
Soil and Water for Raised Bed Patio Gardens
In raised beds, you need a lighter soil than in the garden, similar to container gardening. If you already have a soil mix that you use for other containers on your patio, the same mix is good to use in raised beds as well. If not, choose a soil mix that is loose, rich in organic matter, and lightened with mulch, vermiculite or peat moss. It should be well-mixed, not layered.
Throughout the season, pay attention to the soil moisture. Raised beds on patios will dry out more quickly than garden soil, and keep heat from the sun longer. Water when the soil is dry, which may be daily in hot weather. Always use a thin layer of mulch on top of raised beds around the base of plants, to help them retain moisture better. As for fertilizer, a balanced 10-10-10 fertilizer should be good for most plants in raised beds. Apply lightly in the spring and once a month for the first three months of the growing season, if desired.
What to Plant in your patio garden
You really can grow anything you care to grow in a raised bed, even trees and shrubs if you desire. They are most commonly used for vegetables and fruits, herbs, and flowers, for various purposes. A raised bed planter on your patio that is full of colorful flowers and accent plants is certainly a delight, especially if you use your patio for relaxing, entertaining and recreation.
Consider the uses and attributes of your patio when planning raised bed gardening on it. If it is a small patio just outside your kitchen, mostly used for grilling, a kitchen vegetable garden might be perfect. If you have a small balcony or upper-level deck used for sunning or reading, a small herb garden can serve multiple purposes; to spice up cooking, to add herb fragrances to the air, and to serve as an ornament, perhaps in an attractive round or corner bed. Raised beds of trees or shrubs should be saved for ground-level patios, as they benefit from deeper rooting. However, take precautions to limit the direction of the rooting, as you wouldn’t want tree roots to upturn your patio stones when they grow older.
Whatever you plant, be sure to check the sun requirements and consider that in your choice and placement of the plants, or of the beds. You can determine how much sun your patio gets by observing it over the course of a few sunny days; between 6 and 8 hours of direct sunlight is considered a full sun location, while less than that is partial sun. Some patios, if you have a pergola or roof, may be fully shaded areas, in which case you will need to select very shade-tolerant plants, or consider altering your patio so that more sunlight reaches your garden.
Want to learn more about raised-bed gardening?
Check out these sites for more information.
The University of Illinois Extension has a good resource on benefits of building raised beds.
Iowa State University Extension provides a PDF on building raised bed planters.
The University of Missouri Extension has a complete guide on raised beds.
Raised Bed Gardening Tips goes into great detail about how to garden with a raised bed.