Raised Garden Bed Drainage: Is It Needed?


People often wonder if raised garden bed drainage is needed? Gardening can be a relaxing and fun hobby for all ages. Building your own garden can be challenging, though and the challenges of using raised garden beds can make it extra complicated. But with a little research on my part (and reading on yours), your garden can be successful and bountiful.

Is raised garden bed drainage needed? Gardening requires proper drainage to prevent root rot and pooling water, which can kill the plants. If a garden bed is below knee-high, it does not require special drainage; however, if a raised garden bed is above knee-high, it will require proper drainage to encourage growth and prevent root rot.

All gardening requires proper drainage to prevent over-watering and water pooling at the roots. Most gardening pots have a drainage hole, although raised garden beds sometimes require special drainage material to enhance growth.

Do Raised Garden Beds Need Drainage?

There are many advantages to having a raised garden bed. They can be attractive and sometimes easier to maintain than an in-ground garden.

Having a raised garden bed means that you can build a custom garden complete with pathways. Some older gardeners may even like the advantage of a higher garden bed to prevent back strain.

Raised garden beds can be great, but do they need drainage? Well, just like any form of gardening, the soil needs to have proper drainage in order to promote plant growth and prevent root rot.

What Is The Importance Of Drainage In Gardening?

Having proper drainage in a garden is mandatory for the proper growth of the plants. Drainage is when the water is able to drain to the bottom of the soil, preventing water from sitting near the roots, which can cause the plant to not grow properly or even at all.

Root rot is when the roots of a plant rot from sitting in too much standing water as a result of not having adequate drainage.

Without proper drainage, a plant will slowly die and succumb to root rot. The best way to prevent root rot is to have proper drainage.

What Is Good Drainage In Raised Garden Beds?

First of all, it’s important that we define what a raised garden bed is. Raised garden beds are a form of gardening where beds are made to sit on top of the dirt and filled with soil. This is different than a planter that has a solid bottom and does not sit on the dirt. The garden beds are then filled with soil to the desired height.

A planter with a bottom typically has a drainage hole; however, a raised garden bed has no bottom and instead sits directly on the ground. If a raised garden bed is knee-higher or taller, there will be some extra steps to ensure that there is adequate drainage in your garden.

A garden bed that is below knee-high will usually have enough drainage from the dirt beneath the bed and placing plant-soil on top of the dirt will usually avoid standing water. However, a garden bed of knee-high or taller will require extra materials to ensure proper drainage.

You may be tempted to fill the garden bed with plant-soil; however, there are many other ways of allowing drainage for a raised garden bed that is less expensive and does not waste precious plant soil.

Creating Drainage in Your Garden Bed

When making a raised garden bed, you will need to place material at the bottom of the bed to promote drainage. You can use these materials:

  • Pea rocks
  • Crushed granite
  • Stones

When filling a raised garden bed with rocks or crushed rocks, it should be at least three inches in depth, but it can be more to raise the garden bed up higher.

Once there is a layer of rock, place garden soil on top. The rocks will ensure that the water drains out of the bed while also preventing the soil from getting too compacted over time.

Do Raised Garden Beds Have Bottoms?

Most of the time, raised garden beds do not have a bottom. Instead, they are made to sit directly on the dirt. Containers that have bottoms are called planters, and there is a barrier between the soil and the ground.

The advantage of having no bottom helps the soil drain. It also allows the plant to have more room to grow as opposed to a small planter. Bottomless raised garden beds promote healthy plant growth and proper drainage. Raised garden beds do have the option of having a liner, which acts as a barrier between the soil and the dirt beneath.

Do They Have A Liner?

When constructing your raised garden bed, you may be tempted to use a liner. This is an optional step; however, there are many advantages to using a liner in a raised garden bed.

Using a raised garden bed has its advantages but using a liner can make the garden even better. Here are some reasons why using a liner is a good idea:

  • Weed control – Using a barrier between the dirt and the soil can prevent weeds from growing in your garden. Weeds can deplete the soil of nutrients and moisture, making the plant struggle to survive. A liner can prevent weeds from growing and ensure that all the nutrients of the soil go to your plant.
  • Pest control – Using a liner in a raised garden bed can prevent pests from invading your garden. Snails, slugs, potato bugs, and others can help themselves to your plants, killing any hope of a good growing season. Using a liner in a raised garden bed can prevent some pests from swarming your garden.
  • Drainage – Using a liner in a raised garden bed can promote good drainage. A liner will promote even water distribution and allow the bottom of the garden bed to remain moist.
  • Prevent soil loss – From watering and plant growth, the soil of a raised garden bed can become compacted, and you may lose soil to the dirt. A liner in a raised garden bed will prevent precious soil from being lost to the dirt below.
  • Install raised beds on other surfaces – With a liner, you will be able to install your garden on different surfaces such as concrete, which can be helpful if you live in an apartment or are short on space.

Raised garden bed liners vary on what they are made out of and how they are installed. Some liners only line the frame of the garden bed while others line the entire garden bed. Some are made out of plastic, while others are made from polypropylene fabric or an otherwise breathable fabric that allows water to drain through.

Do Raided Garden Beds Require More Water?

Watering a garden can vary depending on the climate and region, as well as the time of year.

You may find yourself watering up to two times a day during the hot and dry months of summer while you may only water every few days in the cooler months or not for weeks at a time during the rainy season. The improved drainage of raised garden beds makes their watering schedule slightly different.

Raised garden beds often need more water than plants that are grown directly in the ground.

  • Plants in raised garden beds tend to grow bigger and require more water.
  • The garden bed sitting up higher encourages more evaporation.
  • Beds with good drainage can allow the soil to become dry. If the soil is dry beneath the surface, it should be watered to keep the soil moist.

Garden Watering Tips:

  • Water early in the morning or in the late evening to prevent evaporation.
  • Before watering, stick your finger about one inch into the soil. If the soil is moist, it won’t need to be watered.
  • Aim for the base of the plant and avoid watering the plant directly as it can damage the foliage.
  • Consider irrigating the garden and running a drip hose throughout the garden. This makes watering much easier and more efficient.
  • Add organic matter such as compost or manure to the garden to promote healthy growth.
  • Mulch regularly as it slows evaporation.
  • Pull weeds regularly as they will steal the water and nutrients from the soil and cause stunted growth in your plants.

Do Raised Garden Beds Keep Rabbits And Other Animals Out?

A beautiful vegetable or flower garden can be destroyed by pests. Some pests and furry intruders enjoy digging in the dirt while others eat the fruits of your labor. Keeping pests out of a garden can be a feat and it can become extremely frustrating.

Having a raised garden bed can help keep animals out of your garden. Building a raised garden bed at least two feet off the ground can prevent rabbits from digging in your garden and helping themselves to your vegetables. A raised garden bed can also deter cats, rats, raccoons, deer, and any other animal that may wreak havoc on your garden.

You can build a fence to go around your raised garden beds if the animals continue to wreck your garden. You can also put a cover over the top of the garden that is a barrier and can prevent the animals from entering your garden. These can be bought in stores, or they can be simple as a piece of light fabric thrown over the top of the garden.

Building Your Own Raised Garden Bed

With beginner building skills and 2-4 hours, you can build your own garden bed for much less money than buying them premade. By making your own raised garden bed, you can customize it and even create a pathway into the garden.

Before You Start Building

Here are some tips for building your own raised garden bed:

Materials

  • A raised garden bed can be made out of wood, cinder blocks, or concrete.
  • If you are building your garden out of concrete, the pH of the soil will be slightly increased over time.
  • If the wood is being used, keep in mind that it will last for about ten years before needing to be replaced.
  • If you are using wood, use thick wood so it will last longer. Pressure-treated wood is safe to use, although some people prefer to not use it.

Location

  • When choosing a location, find a place that gets 6-8 hours of sunlight each day.
  • If you are going to be placing your raised garden beds on top of a lawn with grass, lay down a piece of plywood or tarp for about 6 weeks to kill the grass which will make it much easier to break up when you are building the garden.
  • Use a spade and break up the soil that will be beneath the raised garden bed before you build it. This will help with drainage.

Size

  • The length of the garden bed isn’t that important but avoid making it too wide as you will be unable to reach the middle or back of the bed for weeding or harvesting.
  • Make the garden bed at least 6-12 inches in depth to allow for the roots to grow firmly in the soil.

7 Simple Steps to Building Your Own Raised Garden Bed

Here are the simple steps to building your own raised garden bed:

  1. With the wood walls up on their side, drive in the wooden stakes at every corner of the wood. Put in additional stakes if you are using longer pieces of wood that need more support.
  2. Drive the stakes about 60% into the ground, leaving the stake exposed. Ensure that all stakes are at the same height as uneven stakes will result in uneven garden beds.
  3. Use galvanized nails or screws to fix the stakes to the boards.
  4. Add in additional rows of stakes and boards as needed until the beds are complete.
  5. Place a liner in the garden bed if desired.
  6. Place a layer of pea gravel or crushed granite at the bottom of the garden bed to encourage good drainage.
  7. Fill the rest of the way with garden soil until the depth desired.

What To Grow In A Raised Bed Garden

A raised bed garden has many advantages, but there are some plants that are better than others when grown in a raised bed garden. Some plants or herbs, like mint, will take over the entire raised bed garden so those types of fast-growing plants are best grown in a separate container to keep them under control.

Strawberries, cucumber, squash, and zucchini are all great plants to grow in a raised bed garden. A tomato plant can be grown in a raised bed garden, but it should have a tomato cage. Most floral plant varieties can be grown in a container garden.

When planting your plants, pay attention to how much water they are supposed to have. Some plants require less water and should probably be planted in a container where the watering schedule can be customized for that plant individually.

Container Garden Ideas

You can grow a theme garden, such as:

  • A pizza garden, which is tomatoes, onions, peppers, oregano, basil, fennel, and Italian parsley.
  • A succulent garden which can be contained to the raised garden bed.
  • A flower garden which can be a variety of colors and plant type.
  •  A mixture of different flavors and colors but be sure you pay attention to the recommendations for each individual plant as some plants must be far away from each other, such as bell peppers and tomatoes.

You can grow a pumpkin plant in a raised garden bed, but don’t be surprised when the vine grows outside of the walls of the raised garden bed.

Other Styles of Gardening

There are several advantages to raised bed gardening, including improved drainage, less of a back strain, and customization options. However, a raised garden bed might not work for you. So, what other types of gardening is there?

  • In-ground gardening is probably the most “traditional” garden. This type of gardening has the advantage of not having to buy soil and having almost endless space. However, the lower level of the garden can be back straining and pests may invade the garden due to a lack of barrier.
  • Container gardening is a great way to garden when in-ground gardening isn’t an option. Many people that live in small homes or apartments use containers to grow their plants. The advantage of the container garden is the option to customize the garden or even rearrange if you want. You do have to purchase all of the soil and the containers themselves can get pricey.
  • Vertical gardening is when a garden is grown along a fence or wall. This is a great space saver, and there are many attractive set-ups that allow you to have a vertical garden in a space where there isn’t enough room for a traditional garden.

No matter the style of gardening, there needs to be proper drainage to prevent root rot which can kill an entire garden if it’s widespread. Raised garden beds offer one of the best drainage systems to combat root rot.

Each style of gardening has its own advantages and disadvantages but no matter what style of gardening you choose, it must be adequately built and offer a drainage system to prevent root rot.

Eyerly Family

The Eyerly Family is a family of 8 that loves gardening. Over the past several years we have been applying what we learn about gardening to our own 16x16 raised back yard garden. Our garden is very prolific and we grow a wide variety of vegetables which we love to eat! Click here to learn more about the Eyerly Family.

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