What Type of Soil To Put in Your Raised Bed
This post is a continuation of our raised bed series with all you need to know about raised bed gardening. So, you’ve built your raised bed, and its sitting empty, just waiting for soil so you can begin planting. What you put in your bed is extremely important to the health and longevity of your plants. Soil supports plant growth by providing 5 core items:
- An anchor for root systems. By allowing the spread and anchoring of roots, soil provides a means for the plant to remain safe and connected to the ground.
- Oxygen – The spaces within good soil allow root systems to access oxygen to grow and prosper.
- Water – Soil provides the spaces that hold water for plant growth.
- Insulation – soil is a natural blanket for root systems during extreme temperature fluctuations.
- Nutrients – Soil provides access to nutrients for plants to grow and thrive.
How you build out your soil composition to provide an optimal growth environment for your plants is key to raised garden success.
There are several questions you need to ask before you get started:
- What are you planting? A little master of the obvious here, but you would be surprised how plans change 🙂
- Are there any special soil chemistry requirements?
- How are you going to irrigate?
- Are there special drainage requirements?
What Are You Planting?
Be sure and check the soil requirements for the types of plants you want to grow. You can put in a broad and general soil mix, but if you want the best growth and healthiest plants, you will need to tailor the soil makeup for your needs. For example, if you are growing carrots, and don’t add sand to create a loose, free growth medium, it will stunt growth. Likewise, a bed that does not drain well will create an environment where bulbs will rot during rainy weather. Any seed site will provide extensive information on the type of soil required for your plants. Example: Johnny’s Seeds.
Are There Special Soil Chemistry Requirements?
pH is one of the most important soil chemistry levels you can adjust for success of your plantings. Slightly acidic pH levels, 6-6.5, are generally most favorable for plant growth, but certain species require adjustments to these numbers. The great part about raised beds is that you typically fill them with soil that is optimized for general plant growth. Some plants may require slight adjustments, and your garden center can advise different amendments to adjust your pH.
How Will You Irrigate Your Raised Bed?
Providing water and a source can sometimes be an afterthought, but it’s easiest build your irrigation out before you add soil to the raised bed. different soil types and plants may require different types of irrigation: drop, sprinkles, spray heads, etc.
Are There Special Drainage Requirements?
Your soil makeup with have a big impact on moisture retention and drainage. Creating a composition that will provide adequate moisture and drain in heavy downpours can be challenging. Certain types of plants do not tolerate poor drainage well, and without adequate drainage you can rot your roots.
The good news? Nowadays there are so many pre-made soil types and amendments at any garden center, you easily add to your raised bed for any type of growth environment. Below is a great “middle of the road” soil composition for your bed:
- 60% Topsoil
- 30% Compost
- 10% Potting Soil
This mix provides texture and air pockets, along with excellent drainage, and is appropriate for just about any type of plant. You can read more on raised bed gardening and all its glory here: Raised Bed Gardens Category Page
What Material Should I Use?
This is the second post in a series on raised bed gardens (First post here: Benefits of Raised Garden Beds). The best thing about raised beds is that you can use just about anything for walls. So how do you build garden box walls? Here is a list of the typical materials you can use.
Wood: The Typical Raised Bed
Creating a wooden raised bed is quite simple, and can range from a few hour project, to one that takes up the whole weekend. You can use just about any type of wood, but ones that naturally prevent rotting are the best choices. Redwood and cedar will provide the most longevity, and turn that beautiful color grey as they age. Avoid pressure treated wood, as the chemicals can leach into the contained soil. How long will wood raised beds last? Cedar and redwood will last 10 – 20 years, other wood types like pine or douglas fir, about 3 – 5 years. 12″ planks are best for the walls, but if you have some carpentry skills, 2-3 feet can provide a convenient gardening experience.
Stone: Raised Bed For the Ages
Stone walls for raised beds have been used for centuries, and endure the test of time. You can use just about any stone, and just stack them or use mortar to make them a bit more permanent. Even if you don’t use mortar, dirt will typically fill the cracks over time for a nice aesthetic.
Concrete: Quick Beds
Concrete blocks can provide a quick and easy road to building a raised garden. You can use traditional square blocks and just stack them, mortar them, or use the manufactured blocks that are so popular at the big home stores. The manufactured blocks are nice as they have grooves to interlock so they don’t fall over. (Home Depot Stackers for Raised Beds)
Metal: The New Raised Bed
Corrugated roofing metal is a new trend in raised beds and if used correctly, it looks quite nice. Combined with a wood top rail, it can provide a nice look and be quite functional. Galvanized metal is rust resistant and will last a long time. You can get the roofing material from any big home store, and its relatively cheap. You just need the means to cut it, and fasten ends.
More on the construction of raised beds in my next post.
How Raised Beds Can Change the Way You Garden
So just what is a raised bed? It is a volume of garden soil contained within a set of walls made of wood, stone, metal or concrete that rises above the normal soil level. It’s a popular method of creating a garden space, but has many benefits.
The Benefits of the Raised Garden
Why go to all the extra effort to build a raised bed garden for your flowers or vegetables? Using raised beds can not only improve the quality of your plants and overall gardening experience, but they can also add an aesthetic factor to the garden with shape and dimension. Here are some of the general benefits of raised bed gardening:
- Less weeding – Ok, let’s face it, I hate weeds. They are the bane of my existence, and I spend many hours of the day picking, pinching and digging to try and reduce their presence. With a raised bed, you are starting with a fresh and clean soil base, and if you mulch correctly, you should have minimal weeds (at least for a season :))
- Control of Soil Chemistry and Makeup – with raised beds, you have total control of the soil, its pH and overall consistency. You can add sand, peat or fertilizer to create the perfect environment for what you are growing. It’s a clean palette, and can be easier to build out than existing soil.
- Better water retention – Because you control the soil and consistency, if you live in areas with sandy soil, you can make sure your plants get adequate water and it is retained during the hot months.
- Minimal soil compaction – Raised beds provide the ability to work an area of soil without walking on it, and compacting it. Loose, fertile soil allows for oxygen to reach the roots, as well as a medium for even water absorption.
- Soil temperature – warmer soil temperatures early in the season and later in the season extend your growth window, and raised beds provide a nice extension. Like a garden blanket, the soil volume is insulated from the extremes of ground and air.
- Save the back – that extra height brings the garden up to you, and for us older folks in the crowd, it can allow for a gardening experience without the bending and kneeling that is a killer.
This is the first in a series of posts on raised beds, follow us here and on Facebook and Instagram to stay in touch. Here are some other links to some great posts:
Raised Beds (Wikipedia)
Raised Bed Gardens