Raised Garden Beds on Concrete: A Complete Guide for Beginners

Installing raised garden beds on concrete surfaces like patios, driveways, or sidewalks is becoming increasingly popular. With more people living in urban areas or having smaller yards, growing food in containers and raised beds allows you to maximize every bit of outdoor space.

But is it really feasible to grow veggies and flowers directly on top of concrete? What steps should you take to set up a successful raised bed garden? I’m here to walk you through everything you need to know about putting garden beds on concrete or other hard surfaces.

Why Put Raised Beds on Concrete?

There are several key benefits to utilizing concrete areas for raised bed gardening:

Makes use of empty space: Concrete surfaces like driveways, patios, sidewalks, and more are often not used. You can use raised beds to turn these areas into useful places to grow things.
Weed Prevention: Concrete surrounds eliminate weeds and grass between raised beds. Less time pulling weeds means more time for planting and harvesting!.
Warms Soil Concrete absorbs heat from the sun, helping to warm the soil in raised beds earlier in the spring. This allows for an extended growing season

Mobility Raised beds on concrete casters or blocks can easily be moved to adjust to sunlight patterns or make room for entertainment areas
No Ground Preparation: With in-ground gardens, you may need to amend and enrich the native soil. Raised beds let you start fresh with ideal growing media.
Accessibility: Raised garden beds raise planting areas to a comfortable working height, which makes gardening easier for people who are disabled or have trouble moving around.

Plan Ahead for Success

Proper planning prevents poor plant performance! Keep these tips in mind before placing your raised beds:

Optimize Sunlight

Make sure to locate your raised beds in sunny areas that receive at least 6 hours of direct sunlight daily. Bed placement is crucial since concrete surrounds won’t allow you to rotate beds to adjust to changing sunlight patterns.

Level the Surface

Use a leveling tool to ensure the concrete pad is flat and even before setting raised beds in place. Avoid sloped areas where water may pool. Shims can help stabilize beds on uneven pads.

Leave Adequate Spacing

Allow ample space between raised beds and surrounding walls or fences. You’ll need room to work and maneuver tools and carts around the beds without damaging plants.

Control Water Runoff

Determine where excess water will drain to avoid pooling. PVC piping, drain spouts, or redirecting beds away from buildings can help control runoff.

Use Deep Beds

At least 12 inches of soil depth is recommended for most vegetables. For root crops like carrots and potatoes, 18-24 inches is better to accommodate their extensive root systems in the confined raised bed space.

Add Mobility (Optional)

Wheeled raised bed frames allow you to move beds out of the way for events then roll back into place afterward. Locking casters keep beds stationary while gardening.

Building Raised Beds on Concrete

A proper raised bed setup on concrete involves taking steps to protect the concrete, contain the soil, and promote drainage:

Protect the Concrete Surface

Line beds with landscape fabric or plastic sheeting to separate the concrete from the soil. This prevents staining and makes cleanup easier if you move the beds.

Contain the Soil

Build an internal “floor” for the bed using hardware cloth or wire fencing material. Line the wire floor with commercial grade landscape fabric to create a sturdy basket to hold soil in place.

Allow for Drainage

Avoid solid wood bottoms that prevent drainage. Instead, use mesh and fabric to contain soil while still enabling excess water to drain away freely through the open bed bottom.

Fill Carefully

Add soil gradually, keeping the landscape fabric smooth and flush against bed walls. Cover fabric edges with soil once beds are full. Avoid excessive digging that could puncture the fabric.

Growing Media for Raised Beds on Concrete

Since container gardens on concrete have limited root space, it’s especially important to use a high-quality growing medium. Look for:

A mix of compost and raised bed soil to improve drainage, moisture retention, and nutrients.

At least 30% compost or composted manure for added organic matter.
Ingredients like coco coir or perlite to prevent soil compaction over time.
Slow release organic granular fertilizer to provide nutrients throughout the growing season.

Worm castings or kelp meal to stimulate beneficial soil microbes.
pH adjusted between 6.0-7.0 to suit most edibles.
Avoid heavy potting mixes that retain too much moisture.

Caring for Raised Beds on Concrete

Proper raised bed care will keep plants thriving all season long:

Water carefully – Avoid overwatering and leaching of nutrients. Target water at soil level using soaker hoses or drip irrigation.

Mulch generously – 3-4 inches of mulch reduces watering needs and moderates soil temperature.
Fertilize regularly – Feed plants according to package directions with organic liquid fertilizers or compost tea.
Monitor for pests – Inspect for common raised bed pests like slugs, snails, and aphids. Treat promptly to avoid infestations.

Weed weekly – Pull weeds when small before they spread rampantly in the rich garden soil.
Replenish soil – Maintain nutrition by mixing compost into just the top few inches of soil rather than digging down deeply.

Alternative Options for Concrete Gardens

If raised beds ultimately don’t work for your space or needs, no problem! There are lots of other ways to cultivate concrete growing areas:

Elevated Planters

Self-contained raised beds on stable legs offer an alternative that won’t stain concrete. Add saucers underneath to catch drainage.

Rolling Beds

Try mounting raised beds on heavy duty casters to create portable gardens that can be shifted around the concrete as needed.

Stackable Pots

Interlocking modular plastic planters allow you to configre movable vertical gardens to maximize patio real estate.

Half Barrels

Drill drainage holes in the bottom of wine or whiskey barrels to create attractive raised bed planters.

Window Boxes

Mount window boxes, hanging baskets or wall planters along vertical surfaces like fences and railings.

Hydroponic Systems

Use vertical hydroponic systems to grow up off the concrete, with no soil required!

With the right setup and care, raised garden beds can thrive on concrete just as well as soil. Just be sure to follow these tips for siting, constructing, filling and maintaining your concrete raised bed garden. Let those vegetable plants grow!

What raised bed topics would you like me to cover next? Comment below! And don’t forget to subscribe to our newsletter for the latest tips delivered right to your inbox. Happy gardening!

Raised Garden Bed on a Concrete Patio | DIY

FAQ

Can raised garden beds be placed on concrete?

Raised beds can be placed on paved surfaces, including concrete and asphalt, with some modifications to support drainage and healthy plant roots. #2: How tall should raised beds be on concrete? Ideally, a raised bed on concrete should be 32 inches tall in order to give the roots access to nutrients and room to grow.

What is the best drainage for raised beds on concrete?

One is to add a layer of coarse gravel to the bottom of the bed before adding soil to help the water drain faster. Another is to ensure that the bed is elevated at least six inches off the ground, which will help water drain away from the roots.

Can I build a garden on top of concrete?

The Royal Horticultural Society recommends laying at least three inches of coarse gravel or stones covered with a geotextile membrane beneath a raised bed built over concrete or pavement. The membrane prevents the drainage material from clogging and getting mixed up with your soil.

Is it safe to grow vegetables in concrete?

Yes it is safe to grow in concrete, and it is also safe to eat that which is grown in concrete. It might not be very productive for some vegetables, but it is certainly safe.