Soil Preparation for a Raised Bed Vegetable Garden

Container Gardening Makes it Affordable to Use High-Quality Organic Soil Amendments

Copyright © All Rights Reserved; Posted January 08, 2012

Bees pollenate garden plants for crop production; photo courtesy Kelly Smith


More and more homeowners are getting involved raised bed gardens. Are you considering building a new bed? Are you getting an established one ready for spring planting? Either way, it’s always advisable to prepare your soil for best results.

Howard Garrett, the Dirt Doctor puts it this way, “Nutritious food comes from nutritious soil. Soil is the key to health.” It doesn’ really get any more basic than that. One advantage with raised beds and/or container gardening is that it is low-scale by nature.

This translates into affordability of operation so you can incorporate high-quality (and thereby more expensive) organic soil amendments.

Should You go with Chemical or Organic Gardening?

Obviously, we here at The Green Frugal advocate the organic method, but we realize that there are still some hard-core Monsanto fans out there. Many gardeners as well as grocery store hunter-and-gatherers are are completely organic-oriented.

And then of course many chemical users uphold the opinion that purely organic practices are too labor-intensive and costly. Luckily, the prices have been coming down over the past few years.

Others experts such as Randy Lemmon of the weekly Gardenline radio show wander down the middle of the road. He opines that the two methods complements each other and you can mix and match. A few years ago he was predominately chemical, but as time goes on he is relaxing.

Begin with the Right Garden Soil

Your base soil, aside from the amendments, needs to be of a texture that encourages the presence of earthworms and beneficial microorganisms. This will in turn encourage healthy root growth. Garrett tells us, “Rich soil is composed of soil particles, air spaces between the particles, water, and energy.”

Should you begin with native soil? Yes, so long as it is appropriate, but it depends on what is native to your area. For instance, in many areas of south Texas, where Lemmon broadcasts, the predominant dirt is “gumbo”. This makes for poor garden soil.

It is also difficult to work with in landscaping projects. Lemmon advocates using rose soil as a basis. This can be bought in bags or bulk.

Add in Your Soil Amendments

Once the base garden soil is in place, it's time to feed it. But before you go shopping, it is a good idea to research the nutritional requirements of what you are going to plant. Then have an agricultural lab test your soil to see if you need to adjust the pH, etc.

Next it is advisable to till in compost. You can buy compost from a local nursery in bags, but why not keep a couple of homemade compost piles cooking? For the bag variety, I really like the Black Kow brand. Your piles can be built up using coffee grounds, grass clippings, leaves (not oak; too much tannin), and scrap vegetables.

How do you know much compost to till in? A commonly accepted rule is a rose soil to compost ratio of 6:1. Try to do this a month or so before you plant anything. This will to give your raised bed sufficient time to rest and get the biological action going.

If you follow the organic approach, Garrett advises spraying the surface of the soil with an organic biological stimulator such as fish emulsion or liquid seaweed. Follow this up with a thin layer of earthworm castings.

Next Add a Layer of Mulch to the Top of the Bed

Mulch plays a key role in vegetable gardens and landscaping projects. The primary function is to slow the evaporation of moisture. Secondly it forms an insulation layer, keeping your soil from going through temperature extremes. Third, it discourages weeds. Finally, it gradually breaks down, which provides valuable nutrients and food for the microorganisms that make for healthy soil.

The best mulches in most cases are hay, pine needles, and shredded hardwood bark. If you choose bark, check the bag label carefully. Be sure it doesn’ mention “colored” or “dyed“. Poor choices are peat moss, grass clippings, and sawdust.

At last, when the chance of a freeze is past, plant plant vegetables. Good choices for your harvest are personal favorites that are costly at your local grocery store. In my case, that means asparagus, tomatoes, basil for pesto, and more. If you go with asparagus, make a dedicated bed, because it will come back year after year.

It is also a great idea to release beneficial insects and add herbs to control pests naturally. Lady bugs will take care of aphids, and for crawling insect pests, diatomaceous earth.

Construction Materials for Raised Beds

There are a lot of choices regarding gardening containers. The most handy and frugal build their own. Untreated pine is cheap and may be used but cedar is a more logical choice because it has proven to be more weather-resistant. It is also a natural insect repellant.

Sealed concrete blocks are a more permanent solution. Warning: A Google search will turn up photos of plantings in old tractor tires. Hardly a wise idea; many undesirable chemicals go into tire production. And who knows what they picked up during their useful life?

Vegetable gardeners living where moles, gophers, and other burrowing pests are a problem may do well to placing a layer of steel mesh in the bottom of the bed before adding the soil.

The word “raised” does not necessarily mean it has too be very high. The whole point is good drainage, effective soil control and isolation, and easy weed control. But on the other hand, many gardeners suffering from chronic back pain benefit from waist-high containers. It even allows wheelchair-bound folks to raise their own produce.


  • Lemmon, Randy. Gardenline radio show. KTRH, Houston, TX
  • Garrett, Howard. (1993). Texas Organic Gardening Book

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