Over the past year as the pandemic caused stay-at-home orders across the country, I found myself tinkering in the yard to update things that had been neglected or were in need of improvements. One such project was to rebuild the raised vegetable garden beds, which were in need of a refresh after years of use as various pieces of wood had rotted away. Growing my own vegetables for the family became a sudden priority; in the early months of the pandemic, going out for grocery shopping was filled with trepidation as we did not understand how COVID-19 spread, and fresh produce was scarce at times. This made me think about what we can do ourselves to promote food security.
The goal of this article is to help anyone interested in homegrown vegetables get started with the process of building a raised garden bed. As there are numerous Websites and articles that cover a multitude of perspectives on this subject, I intended to summarize the key aspects of making your own raised garden in case you are interested in building one yourself.
GROW IT YOURSELF — If you have an existing irrigation system at your home, you can connect a drip irrigation valve that waters your vegetables on a regular schedule.
photo by
Keiji Uesugi
Why raised vegetable garden beds?
The benefits of growing your own vegetables at home range from personal health interests to environmental sustainability, which include better flavor and nutrition, no pesticides, less risk of contamination and promoting food security. One of the most popular ways to grow vegetables at home is using a raised garden bed. The advantages include:
• Ideal soil condition — Soil in raised garden beds prevent soil compaction, provide efficient drainage, make it easy to mix in compost, and allow the soil to warm up more quickly, which is ideal for the vegetables’ roots.
• Ease of installation and maintenance — The raised soil height eliminates the need to bend down all the way to the ground, which can be hard on your back. Since the soil is softer, you can use a small hand shovel to plant the vegetables very quickly, and pulling out weeds is fairly easy as well.
• Protection from some pests — Raised garden beds protect the vegetables from various pests, such as snails and rabbits if you build them tall enough (about 24 inches high). There are various pest control and management strategies to protect your vegetables, which we may discuss in a future article.
What do you need to build a raised vegetable garden bed?
Location and size are the first considerations to make to verify you have the proper site conditions for installing a raised garden bed. Vegetables need at least six hours of daily sunlight, meaning you should not locate the garden bed underneath a tree or directly on the north side of the house where it is shaded year-round. You also want to find a spot that is relatively flat and level, otherwise you will need to grade the ground surface to flatten it. Make sure the lawn and weeds are removed from the site. The site also needs to be big enough for not only the raised garden bed, but also for a walkable area around it with space to crouch down.
For the raised garden bed itself, you can buy the necessary materials at a local hardware store such as Home Depot. The following is a list of materials that are needed for building a raised garden bed out of wood, the simplest building material to use for a DIY project.
Raised Garden Bed Materials and Tools
1. 2 inches by 10 inches by 8 feet Douglas Fir Lumber (or other lumber that is locally available) — To build one raised garden bed that is about 18-and-a-half inches tall, you will need six pieces of boards that are 2 inches by 10 inches by 8 feet. You should note that 2-in x 10-in is the nominal name for the lumber dimension and that the actual dimension of the width and length is 1.50 inches by 9.25 inches. Eight feet is an ideal lumber size because it can be cut in half for a four foot width for the sides. This allows you to build a raised garden box that is four feet wide and eight feet long, which is a good size for being able to reach into any part of the garden bed.
I recommend you go into the store to select the lumber pieces yourself and inspect each piece for any checks, splits and knots around the edges. You can ask a Home Depot representative to cut two boards in half for the sides of the raised garden bed. I decided against using pressure-treated lumber out of an abundance of caution to reduce chemical exposure around the vegetables.
2. 4 inches by 4 inches by 8 feet #2 Douglas Fir Lumber — These serve as posts at the corners and the midway points along the length of the raised garden bed. You can use one piece that is cut into six pieces that are each 16 inches long.
3. Wood Screws — #9 x 3 in. Philips Bugle-Head Coarse Thread Sharp Point Polymer Coated Exterior Screw (one pack) will provide the strength and longevity needed to hold the raised garden bed together.
4. Black Plastic Sheeting 10 feet by 25 feet by 3.5 mil — This optional material can be used to line the sides of the wood lumber to provide some moisture barrier between the soil and wood. Do not line the bottom, as that discourages proper drainage.
5. Soil and Potting Mix — More information on this is listed below.
6. Saw — If you are not able to get the lumber cut at Home Depot, you will need a saw to cut the 2 inches by 10 inches and 4 inches by 4 inches lumber at home. You can use a hand saw, but it will be much quicker to use an electrical or battery-operated circular saw or jig saw.
7. Drill — You will need a drill for pre-drilling holes and driving the screws to fasten the wood lumber together.
8. Non-toxic Wood Sealer — Treating the lumber with non-toxic wood sealer such as Raw Linseed oil or pure Tung oil can extend the life of your wood raised garden bed.
Cucumber plants need support since they grow like a vine. Six-foot tall sturdy stakes and twisted sisal twine work well for this purpose.
Soil for the Raised Garden Beds
To fill your raised garden bed, you will most likely need to purchase soil unless you have been creating your own compost for years. If you are filling your bed for the first time or are building multiple beds, getting an order delivered from the local landscape supply store will be worth it. According to Gardeners.com and other raised garden bed articles I came across, a general consensus for soil composition is:
• 60 percent topsoil — This can be extra dirt in your yard or purchased from a local landscape supply store. This translates to 1.07 cubic yards in a 4 feet by 8 feet by 18 inch-raised garden bed.
• 10 percent potting soil — Kellogg Raised Bed and Potting Mix has worked very well in Southern California. This translates to 4.80 cubic feet or two-and-a-half bags worth of Kellogg Raised Bed and Potting Mix in a 4 feet by 8 feet by 18-inch raised garden bed.
• 30 percent compost — Compost from your kitchen scraps is ideal and the cheapest option, but if you do not have this, your local landscape supply store should be able to deliver. This translates to 0.54 cubic yards in a 4 foot by 8 foot by 18 inch-raised garden bed.
Watering
The simplest way to water the raised vegetable garden bed is manual watering with a hose and watering wand with a gentle rain feature. If you have an irrigation system installed in your yard, I highly recommend installing a dedicated drip irrigation valve and drip tubing so that you can ensure that the vegetables are on a watering schedule that will not get accidentally missed as can happen with manual hand watering. You will need to make sure there is a zone available on your irrigation controller for a new drip irrigation valve. You can attach drip tube to the valve, which can be run through the raised bed with emitters extending from it.
If you have an existing irrigation system at your home, you can connect a drip irrigation valve that waters your vegetables on a regular schedule.
Vegetables in California Climate
California is soaked with year-round sunshine, which creates the opportunity to grow vegetables throughout the year. Many vegetables grow the best from late March to September, but some vegetables, such as lettuce and spinach, can grow in the cool weather as long as they get sunlight exposure. Below is a list of vegetables that work very well in raised garden beds. Ultimately, the vegetables you grow depend on your taste and preference, but it is great to gain confidence with these resilient vegetables that are commonly in stock at Home Depot or your local garden store:
• Tomatoes — There are numerous varieties available from small cherry tomato size to large Big Beef tomato plants for sandwiches. Tomato plants need plant support, such as a tomato cage, so be sure to purchase one for each tomato plant you get. The spacing of tomato plants varies by the variety, but 18-inch-to-24-inch spacing is common.
• Romaine Lettuce — Romaine lettuce grows robustly and quickly. You can also make it last for weeks by only taking off a few leaves at a time. Lettuce can be grown about 12 inches apart.
• Japanese Eggplant — These vegetable plants tend to do well with regular watering. I suggest using a stake for plant support.
• Kale — These plants are very nutritious and can produce an abundance of leaves. Space them 18 inches to 36 inches apart as they can take up a lot of room.
• Onions — Onions grow well in raised garden beds. This year I am interplanting them near cucumber and kale plants in an attempt to see if they can successfully grow close to other vegetable plants.
• Broccoli — This vegetable plant grows well in the springtime. I planted a few in early March and the crown is starting to appear. The leaves spread out, so space these vegetable plants at least 18 inches apart.
• Zucchini — These plants can produce for several weeks throughout the summer, but they do take a bit of space. Allow for 24 to 36 inches spacing, but you may be able to sneak in low-growing plants and herbs between them.
• Cucumber — I typically grow Japanese cucumber in my vegetable garden and this season have added a straight cucumber plant. They grow very well in raised garden beds and need plant supports such as stakes with strings drawn across.
The raised garden beds have been a great source of nutritious and delicious produce for the family. Sometimes there is so much being produced that we share with relatives and donate to the local food bank. Planting and maintaining the raised garden beds also provide a great learning activity for the children in which they learn how to work with nature and principles of a sustainable lifestyle. Growing vegetables are a reminder of the blessings we receive daily and the importance of taking care of our environment.
Keiji Uesugi, PLA is the principal of the landscape architecture firm, TUA Inc. in West Covina, Calif., and a faculty member of the landscape architecture department at Cal Poly Pomona University. A licensed landscape architect with more than 20 years of professional experience, he is an expert in cultural landscapes and Japanese gardens of North America. He can be reached at keijiu@gmail.com. The views expressed in the preceding column are not necessarily those of the Nichi Bei Weekly.
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