How to Build a Raised Garden Bed for Growing Vegetables–with Gopher Protection

The Gophers Ate Our Garden

When we first moved into this property and began gardening about 20 years ago, we enjoyed a grace period as regards gophers. We sheet-mulched the ground in preparation for planting, and the kale, pumpkins, and other veggies did well. But after a couple of years, the news must have gone out on the gopher equivalent of Twitter, and from then on, the garden is a metropolis of underground gopher activity, and we had to abandon planting direct in unprotected ground. We had to build raised beds for the vegetables, dig up roses and echinacea and other perennials and transplant them into containers, and all trees and shrubs had to get planted in gopher baskets. Even our gopher protection attempts had to evolve in sophistication over the years as the gophers breached some of them.

Chatting with other gardeners in Sonoma County usually includes frustrated discussions of gophers, and there is a rumor (or is it true?) that it was the gophers that ruined the survival of early Russian settlers here.

Fort Ross, despite its influence in international affairs, did not prove to be a successful colony…. The reluctance of the colony’s hunters to engage fully in agriculture, combined with the coastal fog and indigenous gophers and mice, resulted in a string of unprofitable years in the late 1830s. By 1839, the Russian-American Company sought to leave Fort Ross.

http://picturethis.museumca.org/timeline/early-california-pre-1769-1840s/russian-presence/info

So, to garden here at all feels like a triumph of sorts! But to give the resilient little critters their due, they are an important part of the ecosystem and this makes me forgive them a bit when they eat my beloved plants. Some years ago, I saw a show on PBS or someplace on the regeneration of ecosystems after a volcanic eruption, and how important gophers were to that–a surprising find. I couldn’t find the video clip, but this audio clip seems to be similar. So, while they can devastate a garden, they do have an important role in the environment. And of course they are no doubt an important part of the diet of hawks and owls and coyotes and so many others.

But within days of the volcano erupting, the local ecosystem started to bounce back. Thanks to some unassuming little animals that spend lots of time underground. “The pocket gophers were the ecological heroes of Mount Saint Helens.”

Scientific American and Emory University paleontologist and geologist Anthony J. Martin.

Even so, I grew up in a place without gophers, and to a gardener, it seems a cruel fate to have to deal with them, and not be able to simply plant things in the open ground. When we have to also protect from deer and birds, the veggies end up looking imprisoned, in what we jokingly call high-security gardening.

So if you are in an area of the world where you can plant direct in the ground, I’m delighted for you (and jealous)! But for anyone who shares our gopher challenge, here is what we ended up with for garden beds for our veggies. (If you are planting trees or shrubs in the ground, see this other gopher article about that. For a list of possible gopher-resistant plants, see here.)

Making a Gopher-protected Raised Garden Bed for Growing Vegetables

These are not without expense and effort, but the earliest ones we made are still intact and those are 15 years old—which means they have far outlasted wine barrel planters and even most ceramic planters. There is a diagram below.

These gopher-protected raised beds are constructed from 2” x 12” redwood lumber. Most of the beds are 10 feet long and 4 feet wide, with some half-sized beds of 4′ by 4′. Originally we made them 5 feet wide, but those are hard to reach into the middle of. Most are 24” high. This is because gophers will scale the single 12” layer. We don’t seem to get many crawling up into the 24″ high beds, although I’ve heard it said they can do that too. And, you want as much protected depth as possible for the vegetable roots.

If you don’t have a saw, some lumberyards will cut the redwood boards for you the correct length, for a small fee, depending on how busy they are.

First, prep the ground as level and firm as you can. Place a board across it in various directions and put a level on top of the board, to see if your ground is level. When that is done, place an old wool carpet or big piece of old felt on top of your ground where the bed will go, so that it will extend around the edges by a few inches. I’ll explain why later. Now, measure and cut a large enough piece of gopher wire or hardware cloth to extend past all four edges of what will be your finished bed–by at least a five inches all the way around. I recommend that you try to use wire that is as wide as you need it to be, so that you needn’t attempt to “sew” pieces together. Gophers may breach that. Place the wire on top of the wool.

Now begin building your bed on top of the stacked wool carpet and wire.

For the corner posts, we use 4” x 4” redwood, and 3.5″ decking screws drilled through the outside of the lumber into the 4x4s. We’ve also experimented with using 2” x 2” corner posts, at a length that extends up above the bed by 2 feet (see photo). This makes handy above-soil posts for draping bird netting or frost covers over. The 2×2’s will rot faster than the 4x4s but so far the beds with those have lasted a 3-4 years. For corner fastening, you can also use any number of metal corner brackets that are available, if preferred. When you assemble the bed, it’s extremely handy to have a second person. Use a carpenters square to check for symmetry. If you want more detailed instructions than I’m giving here, let me know.

Assemble the bottom level first, starting at a corner and working your way around, checking for 90° corners with your carpenters square. Then add the upper row. Don’t make the mistake I did: make sure that if one end has the short boards aligning with the inside of the longer boards, that you do the same on the other end.

Now congratulate yourself! That was a big job. Just a few more steps and you will have a new garden bed!

Now to affix the gopher wire. On one long side, bend up the gopher wire or hardware cloth and tack on to the outside of the bed, using large carpentry staples and a staple gun (or hammer in U-nails). You can either do this all the way around, or, if you have a second person and would prefer to staple standing up instead of bending over in order to save back strain, then carefully lean the whole bed up onto the side you already tacked on, then finish stapling the other three sides. The second person should hold the bed for stability — to keep it from falling or torquing.

Do not repeat our mistake of tacking the wire to the inside of the beds! It looks nicer but the gophers may wedge dirt up along this seam (ahem, they probably will), pressing it away from the board far enough for them get into the bed. This happened to us and we had to painstakingly remove the soil, re-affix the wire to the outside and refill the garden bed.

Now to explain the wool. The reason the wool carpet or felt is used is this: the gophers are pros at soil-moving, and they will tunnel underneath these beds making open caverns, and your precious soil will sift out below. The gophers keep moving soil until the luscious veggie roots are within incisor reach from below. Gophers apparently don’t like hair, and wool is, after all, hair. So, the theory is that they won’t eat through the wool, and so it not only is another layer of gopher-proofing, but holds your soil up inside the bed, and yet still drains excess water out. If you don’t have old wool carpeting or an old large wool rug or felt, you could check with a local carpet installer who may give you the next one they remove for replacement. We once got a very old and tattered wool rug from a salvage place.

What to fill the bed with? Well, this is embarrassing to admit, but we splurge $ on the garden bed filler and use a very high-quality organic potting mix called Ocean Forest, from FoxFarm. We get it delivered on a pallet via Harmony Farm Supply (see Resources). Our soil here is very sandy and low in organic matter, and has some pernicious weeds. So for these precious raised beds, we fill them with new organic potting soil. The good news is that though we top them up before each new crop planting with another sprinkling of potting soil, or organic fertilizer or worm compost, the bulk of the potting soil stays in there permanently. The potting soil resists compaction, but when needed, we fluff it with a digging fork. In some of the first garden beds, we filled the bottom with straw and other materials to save on potting soil. If you have great quantities of your own weed-free compost–wonderful! Or, you can, of course, buy truck loads of compost from local composting companies. If you have a good source for that, great. One of our local sources had trouble with clopyralid showing up in its product for awhile. It wasn’t their fault–their compost was made from landscaping clippings people brought in, and they may have worked out that issue by now, but we like the Foxfarm so much we keep using it.

On rare occasions, we still find tunnels in a garden bed. If plant roots are not eaten, this could be rats or mice–as they also burrow. If a gopher does get in, we trap it. Don’t try flooding. It can work eventually, but uses too much water and also washes away all your good nutrient. More on this later.

Over the years as our energy level allowed, we added more beds. We currently have 10 of the large beds, 6 half-sized ones, 1 large square one of only single height and a few others that have perennials like echinacea or other herbs and flowers in them. We build more as we are able, but this amount keeps us in most of the veggies we like to grow: beans, beets, broccoli, carrots, cucumber, garlic, kale, leeks, lettuce, onions, parsley, peas, peppers, spinach, tomatoes, winter squash and pumpkins, zucchini, and some others.

I’ll do another post about other gopher-related stuff soon.

Meanwhile … happy gardening! Let me know how it goes!

Read the blog post about gopher-protecting trees and shrubs here.

Review possible gopher-resistant plants here.

General info on gophers here.

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