Can you build raised beds on concrete

However, compost is key for raised beds on concrete, both to provide nutrient-rich soil for the plants and to help retain moisture. It is recommended you avoid potting soil on its own—its light texture leads it to drain and dry off too fast. Before building the raised bed, you can also pour some water over the surface and see in which direction the water drains.

This will help you determine the best place to build your raised bed. Ideally, you should avoid any area that gets waterlogged. Even the most well-built raised garden bed may experience occasional leakages due to heavy rain or excessive watering. The water that comes off the raised bed is full of soil and may stain the concrete around it.

To prevent water runoffs that may cause stains, avoid overwatering, and use a soil mixture that provides good water absorption. Another good idea is to cover the raised bed during winter.

If leakages do occur, promptly wash off the runoff water to keep the concrete surface clean. Concrete is alkaline and, over time, may impact the pH of the soil in the raised bed. Knowing the pH of the soil is important because it will help determine which plants are more appropriate for the soil you add to your raised bed.

Most garden plants prefer a pH between 6. An alkaline or sweet soil has a pH of 7. Gardeners are easily able to test the pH of their soil using a store-bough test kit and adjust the acidity of their soil as needed. Acidic soil can be treated with grounded limestone or wood ash, while alkaline soil can be treated with compost, ground sulfur, or gypsum. Consult your local garden experts to help determine the best way to adjust the pH of your soil.

Raised garden beds on concrete are an excellent way to increase limited garden space or create a garden in a barren area. I had considered depaving this unused section of the driveway, but decided to build raised beds on top of it instead.

See the next section for more details about that decision. It was totally worth it! Even though my raised beds were in the shade, they consistently produced around 80 pounds of vegetables each season. Through this experience, I discovered several keys to growing successfully in raised beds on pavement.

The question of whether to depave your garden site or to build raised beds on top of the impervious surface comes down to your goals and the physical labor involved. I love the idea of depaving a hard surface. Our ecosystems desperately need more rainwater to infiltrate the soil and recharge the water table right where it falls, rather than overwhelming local watersheds.

And why allow it to run off when it could easily water your garden for free? The removal process may activate toxins that have been lying dormant, causing them to leach into your soil as well as your local watershed. Another downside to depaving is the labor involved. Be prepared to cut and pull up the paved surface using tools like a sledgehammer, jackhammer, and crowbar. If building raised beds on top of pavement is still the best strategy for you, then read on! Your crops need room to stretch their legs and send their roots down, down, down.

The deeper the raised bed, the more room crops have to grow a strong foundation. A deeper bed also helps crops to be more self-sufficient. It holds moisture longer, which means less watering. In addition, crops with more and deeper roots can access more nutrients in the soil, which means less fertilizing. Therefore, I recommend a raised bed that is a minimum of 24 inches tall and an ideal height of 32 inches. The taller the better! My own raised beds on my driveway were 24 inches tall, and they performed well.

But they conserved water by being partially shaded. Would you like more strategies for growing food in small-spaces? Filling raised beds on pavement is a bit different than filling raised beds on permeable ground. To decide how to fill the bed, we need to understand how rainwater behaves inside a raised bed on pavement versus a raised bed on the ground.

As gravity pulls rainwater down through a raised bed, it nourishes the water table in the subsoil below it. Once the water table has been replenished, excess water drains away into the local watershed. As the raised bed dries out, it wicks moisture up from the water table underneath. With the appropriate mulching practice , it can oftentimes tide the garden over until the next rain.

The garden makes rainwater deposits and later makes withdrawals as needed. This setup is a bit more contrived than the natural system described above. Gravity pulls rainwater down through the bed and, rather than hydrating the water table below, it is whisked away on the hard surface. Your first line of defense against soil erosion is filling the bottom of the raised bed with about six inches of gravel.

This helps with drainage and prevents the soil from washing away in a heavy rain. It also reduces the chance of garden crops coming into contact with the pavement. There are lots of options for filling the space above the gravel, and this depends on what kind of organic matter you can gather. Your goal is to find high-quality sources of organic matter, which is important for growing healthy crops.

Living soil has what are called soil aggregates, those sticky components that hold moisture in the soil.

This is in contrast to sterile potting soil that you might purchase in bags. Raised beds built on dark pavement will usually have higher moisture needs than those built on a lawn or natural substrate.

Keep this in mind when considering watering frequency. Hard surfaces will prevent beneficial creatures like earthworms from entering raised garden beds from below. Thankfully there are other ways to bring worms into your garden. Not only will these amendments improve your soil health, they will also add beneficial creatures to the mix.

Patio Containers and Planters If your space is too small to accommodate raised garden beds, patio planters and other gardening containers are an excellent way to cultivate edibles in small spaces. Are planters and patio containers right for you? Planters and containers are right for you if you: Are trying to grow food in a small space. Want to be able to move your plants inside during the winter or to different locations during the growing season. Have access to nutrient-rich potting mix to fill your planters and pots.

Are working on a limited budget or want to start small, adding a few containers or planters at a time. What type of container or planter is best? You can prevent this by lining with a plastic pot.

Larger pots are heavy to lift and awkward to move. Locating your planters Before purchasing your plants or planting your seeds , mark out areas of sun and shade in your yard, patio, or balcony, and place containers accordingly. Related: Container Gardening Secrets — Ideas to Inspiration Feeding and watering Planters and containers will need more regular fertilization than raised beds, since your plants are working with less soil and a smaller space to search for nutrients.

Soil mixes for patio containers and planters Garden soil is often too heavy for container growing and plants usually do better with a lighter, more porous soil mix. Getting the most from your space In general, you can plant containers and planters more densely than regular garden beds because there are more nutrients in potting soil mixes.

Related: How to Create a Balcony Garden Ideal vegetables for container and planter gardening While almost any plant will grow in a container, some are easier to grow than others. Lettuce Works well in large, shallow containers, such as a window box or raised garden planter. Great for those semi-shade areas protected from the heat of summer. Carrots Ensure containers are at least 12 inches deep. Rolling patio planters work well for carrots. Cucumbers Plant in a container no smaller than 1 gallon.

Include a stake or trellis for vines. Tomatoes Use a 5-gallon pot or bushel basket. Choose determinate varieties for a contained plant, or try indeterminate varieties if pruning and trellising are possible. Herbs Basil, thyme, oregano, chives, rosemary, and sage all adapt well to container growing. Vigorous spreaders like mint do well in pots, which can help contain their growth.

Squash Choose space-saving or bush varieties and plant into a 5-gallon pot or larger. Strawberries Choose everbearing or day-neutral varieties to ensure a full season harvest. Strawberries are perennial, so be sure to store in a sheltered location over the winter.

Refresh the soil in subsequent years with new potting mix, and prune where necessary to ensure the best harvest possible. Peppers Ensure plants receive at least eight hours of full sun.

Plant smaller varieties in a 2-gallon pot. Larger varieties will need a 5- or gallon pot. Beans Plant bush beans in planters or pots with full sun. Pole beans are good container companions for shorter plants providing trellises or stakes train the vines up and away. Vive la Revolution! From Our Shop.

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