Raised Bed Gardening

by Irving H. Baxter of Potsdam, NY

We gave up on gardening for a while. Like so many other places, our home had only one suitable location for a garden. The other areas on our property didn’t have good sunlight exposure or conflicted with other uses. Nope. It had to be on the south side of the house or nowhere. For a long time it was nowhere, for in addition to ample sunlight and convenient access, the site was blessed by quack grass only a duck would love, more clay than your average ceramics factory and stones that would put any rock quarry to shame.

Being the stubborn sort, I tried it anyway for a few years. Clay soil can be amended; stones can be picked and removed. We added compost and picked rocks until the cows came home and left again, but still the plow wouldn’t cut in, and the tiller bounced off it like a rubber ball on a concrete playground. Carrots had gnarled, twisted roots that were more in the air than in the soil. The tomatoes and other pre-started plants did fairly well, as long as we chiseled out a bucket sized hole and filled it with compost to plant in. Of course, in a wet year, it was like walking a greased slide, and in dry years it was a baked ceramic parking lot. Eventually even my stubbornness had to admit defeat. We smoothed the top as best we could with rakes and bulldozer, leveled the rocks into a semi-smooth surface, and let the quack grass have its way with our lovely southern exposure and hiked to the store for our fresh vegetables.

A few years passed, and I kept looking at that perfect, sunlit garden site and watched the price and quality of fresh veggies skyrocket. I knew there had to be a way. Researched in all the gardening books I could find and skimming through every gardening magazine on the newsstand lead me in only one direction. That soil (to describe it charitably) had to go. My first thought was to have a front end loader and other machines of mass destruction come in and take away the top foot of so-called soil, and replace it with the sandy loam so glowingly described by gardening gurus. Pricing this option yielded a massive case of sticker shock. Removing the old soil(?) could be afforded with difficulty, but replacing it with the perfect topsoil cost a king’s ransom!

My mind whirled (and threatened to turn into butter) as I tried to reduce the cost and still get the job done. Why waste good soil on walkways? I would simply mound the purchased dirt into windrows and plant there. Good idea. Patting myself on the back, I recalculated the cost. Hmmmmmm. Better, but still too hard on the budget. Maybe if I only had the top six inches removed — WAIT! Why have ANY removed? I could kill the quack grass with plastic sheeting and pile the dirt in wide neat rows. Still – the rain will spread it out. The kids and dogs will stomp it flat. Better contain it a bit. Boards along the edges soon became wooden boxes to hold the precious soil tightly in neatly organized containers, container gardening was something there was a multitude of information about.

As is usually the case with me and my bright ideas, I got the cart before the horse. I had found a person who would sell me good topsoil at a substantial discount. Figuring I better hurry before it was gone, I ordered two dump truck loads. Within days, two massive piles of friable, deep black garden soil sat next to the crab grass orchard we were going to make into a showplace. Unfortunately, I hadn’t looked far enough ahead to see the need for materials to build these raised beds from, so we hurriedly started gathering whatever planks and posts I could get my hands on. It was a motley selection, but hammer and saw soon had our first seven beds built. Four feet wide, by eight feet long by one foot deep, each was calculated to hold (for the most part) one kind of vegetable. Seven beds was equal to seven vegetables, with the exception of the lettuce bed that also held radishes, kohlrabi, green onions and other salad ingredients. For obvious reasons, we called that one the salad bed.

The planting part was still in the future as we finished nailing the planks to the 4×4 corner posts, leveled them roughly and passed out shovels to begin moving the multi-ton piles of rich loam into the beds. Although interested and willing helpers during the construction phase, our five sons soon discovered homework that simply had to be done right then, chores that needed to be done just then, and other mandatory reasons they couldn’t help dear old dad in the garden. Being the father of five boys, I had earned a Master’s Degree in Applied Threats & Coercion, and soon put this problem in our past. I considered threats of violence and loss of privileges, but settled on simple old-fashioned bribery. A crisp five-dollar bill to each of them when we were done, and the dirt was flying by sentence end. Cautioning them not to waste the soil, I slid back casually and assumed my rightful role as supervisor, leaning on my shovel to keep it from falling over.

Worried that the evil quack grass would grow up through our new soil and take over the beds as well as it had the rest of the garden site, I had lined the bottom of each bed with heavy plastic sheeting to smother it out. In retrospect, I did it wrong. Twelve inches of fresh soil is enough to kill the weeds, and the plastic would have been better used on the sidewalls of the bed. Being raised up into the wind, the beds dried at a rapid pace. When other gardeners were watering weekly, I had to water every other day to maintain adequate moisture levels.

To skip ahead, those first seven beds had a few problems, but were nonetheless the best garden we had grown to date. The tomatoes grew spectacularly and ripened on time. Carrots grew long and straight. The peppers did well after a shaky start, and the other vegetables did well above average. No doubt was left in our minds. This was the ONLY way to garden. Not only was production well beyond expectations, our backs no longer ached for days after working in the garden, nor was there a profusion of weeds everywhere we looked. To fit in all the plants we had, the spacing recommendations on the seed packs were thrown out the windows, and we stuffed plants and seeds in every spare inch. This led to our most dramatic discovery – intensive cultivation, or living mulch as it’s also known. I have now found out that this is a poorly kept secret and has been used for centuries in China and France (and doubtless other places as well). By carpeting the growing space with desired plants, weeds simply cannot compete for food, water and sunlight once the vegetables get a good start. We weed quite a bit the first few weeks to give the seedlings a chance, but hardly any after that. Even here, the raised bed system works with you by allowing the gardener to sit on the edge and pull weeds comfortably, or kneel alongside the bed and using the side to support the body while reaching and yanking the pesky green vermin.

Intensive cultivation in the raised beds worked wonderfully well in another regard. The sun can hit the sides of the beds as well as the top, thawing and warming it to planting temperature several weeks faster than our flat garden. This spreads out the planting chores and allows a jumpstart on the growing season, a very important consideration in our climate. By getting my beets and carrots in early, they are ready for harvesting by mid to late July. I saw them getting mature, and planted another crop between the rows of existing plants a few weeks before the anticipated harvest. The new seeding germinated well, and I was ready to pull the mature ones by the time the new crop needed the light and space. In combination with six inch row spacing, this double cropping yielded us almost enough carrots for a family of seven for almost a full year in a 4-foot x 8-foot space. (NOBODY can grow enough beets in one year for these boys.)

Late frosts can do serious damage (like killing) early plantings. At 4 x 8 and 4 x 12 feet, the early-planted beds are easily covered to protect them from cold days and colder nights. I neglectfully left the corner posts long when constructing the beds, but discovered a very useful purpose for this mistake. We had a dog that assumed we were building her a series of elevated sleeping platforms, and would lie on each bed regardless of any plants trying to grow there. I placed a heavy nylon twine around the perimeter at the top of the posts to discourage her, and accidentally discovered the idea of mini-greenhouses. Inexpensive clear plastic sheeting can be placed over each early-planted bed, and tied onto the bottom planking to warm and protect the young plants. Care must be taken to open up or remove the cover on warmer days, but the overall effect is wonderful in extending the season on each end.

This procedure can also be used in pest control. The free ranging guinea fowl we use to rid us of slugs, ticks and other insects unfortunately find ripening strawberries to be the perfect dessert after a meal of bugs, as do young boys who haunt the garden when we’re not looking. (I’m not sure about the boys eating bugs but it wouldn’t surprise me either.) In either case, medium mesh bird netting from our local garden center draped over the twine and firmly attached at the bottom cured both problems while still letting in the bees that do the pollinating. It’s not too much of a bother to lift and fold over each side every few days to pick the ripe and unnibbled fruits. While we have yet to try it, I also believe some nylon fly screen used in the same fashion will reduce or eliminate the cabbage loopers that plague us. It’s on our list of things to get and do, but for now the BT spray works fairly well.

Alas, all is not perfect in our “Garden of Eatin’” (as we call it). In addition to the rapid drying, we did discover a few other areas that needed correction in future expansions. The purchased topsoil had a clay content higher than we liked, and required us to remove one half of it, and add compost, sand and barnyard wastes to remediate it. The removed soil was similarly amended, and placed in new beds to augment our available space. We also discovered that twelve inches was a little too low for maximum comfort, and the new beds are eighteen to twenty-four inches tall, as well as twelve feet long in most cases. Rough leveling is also not quite good enough, allowing heavy rains to run off the low end. We now use a carpenters level to ensure that all sides are the correct height to prevent this. It also makes better use of sloped ground, giving the effect of a terrace. To keep the dirt in during tilling, and to further prevent wasted rainfall, the sides extend 4 inches above the soil to allow it to soak in, no matter how fast it comes down. The insides of the boxes are now lined with heavy rubber to slow evaporation and ease the task of watering in periods of dry weather.

Two feet of soil is not needed in most cases, so we fill the first 8 to 10 inches with coarse wood chips we get from the highway department cleanup crew, and fill the rest with our soil mixtures. Purchasing topsoil is also an expense we avoid for the most part now. We have a quantity of coarse sand on our property, and manure and litter from the farm animals. By composting it over the summer, it combines with the sand, peat moss and whatever other organic matter and miscellaneous soil we have from here and there to produce a fertile, friable planting medium. The exception is when our neighbor who owns a dairy farm scrapes his feedlot. I purchase the mixture from him at very reasonable rates. It’s composed of roughly 50% soil, 25% cow manure and 25% chopped alfalfa and other green chop. He delivers it in his PTO spreader and it tosses up into a nice light pile to finish composting. This is primarily used whenever we undergo a major expansion of our raised beds. This allows us to hoard our own manure/compost mix for topping off each bed after a crop is removed.

Other drawbacks include the fact that it is not reasonable to grow crops that require a lot of space for the yield. Sweet corn, potatoes, squash and pumpkins take up a lot more room than they are worth in raised beds. We cannot give up these crops, and so plant them in a traditional “flat” garden out back so they can run and spread to their heart’s content. Peas also do not do well in raised beds, likely due to the extra warmth in them. These also are planted in the flat garden, along with zucchini and other space hogs.

Because we plant so heavily, we must feed the plants heavily. It is not unusual for the soil in a 32 square foot bed with 32 broccoli plants in it to subside up to 3” during the growing season. Some of this may be due to setting, but most is because of further breakdown of the compost and utilization by the plants to produce their crops. The rich compost we add each year provides most of their needs, but we have found that small doses of Miracle Gro plant food at certain stages of growth boosts yields considerably. For those gardeners wishing to remain organic, manure tea, blood meal, rock phosphate and wood ash can provide a lot of the same nutrients in combination with rich compost.

Mixing in the new compost every year and whatever amendments we desire can be a back breaking task. We used a spade and dung forks which did the job fairly well, but at the expense of time and energy which we didn’t always have. We solved this problem when we purchased a small rototiller that we lift into each bed to mix and fluff the soil. It tends to buck and jump when the slashing tines hit a side or end wall, but it can be controlled with practice. This procedure is hard on our aging backs, but there’s usually a teenager around willing to do it for another of those crisp five dollar bills. (Let us hope they don’t discover the concept of inflation any time soon!)

One major boo-boo we made was to not take into consideration future needs in the garden. Our walkways between the beds are wide enough for neither the garden cart nor the lawn tractor and trailer. All soil coming in and produce going out must be hand carried or wheeled in a contractor’s wheel- barrow. It’s not a major problem, but if we had it to do over again… Other changes we would make is to be more precise in laying out the beds. We stuck them in wherever we wanted, with little regard towards alignment. Consequently, the beds are at an angle to the house, and the rows wander a bit like a drunken sailor. Not an important thing, but it does hinder the aesthetics of the plot.

In the years since we started on this raised bed adventure, we have revised our policies and practices considerably. The third year we used our beds, we experienced a drought such as I’ve never had to deal with before. Nonstop heat and drying winds combined with the total lack of any precipitation to bake everything rock hard. I spent 3 to 4 hours each day keeping a minimum of moisture on the plant roots. We really tested out well that year, and I’m very grateful that it was up to the task. Beth & I sat down and made an honest assessment of all the benefits and drawbacks of the beds, and came up with ways to minimize the downfalls and optimize the benefits. The major problems were the drying effect and the deterioration of the lumber. We solved both of these problems with one procedure. I procured (by legitimate means!) a large quantity of heavy rubber sheeting. This is commonly used as liners for ponds and water gardens, and also as a membrane on commercial roofs. A roofing contractor was replacing such a roof in town, and was more than glad to have me haul it off to save him the landfill costs.

With much grumbling and applied persuasion, the boys and I dug out the soil around the perimeter of each bed, right down to the original soil level. The rotted boards and corner posts were replaced as required with cedar, leaving a small gap between each board to allow drying of all surfaces. I used 3 inch galvanized deck screws to facilitate any necessary replacements in the future. A sheet of the rubber was cut that just reached the ground inside the bed and would overhang the top board by a couple inches, long enough to go around the entire perimeter. The top edge was lapped over the outside and tacked in place on the outside face with roofing nails every six inches or so. This allowed the strain to be held by the board instead of just the nails.

We knocked down and spread out the soil that had remained in the center of the bed, and mixed in compost and peat moss with the removed soil to top off the bed before moving on to the next bed. By starting on a couple beds left fallow for that purpose, and rebuilding each bed as the crop was removed but before the late summer plantings of fall crops, we were able to do the entire garden with a minimum of disruption to the continuous flow of crops. The rubber (which could be replaced by any heavy plastic) has reduced the moisture loss to a minimum, allowing frequencies of watering not much more than our conventional flat garden. It has also kept the wooden boxes in much better shape by keeping damp soil from contacting it. When a particular board or corner post needs to be replaced, it also holds back the soil, allowing me to unscrew the old one and insert a new one with hardly any fuss at all.

Our original seven beds have expanded to 28, with quite a few more planned for future years. I plan on at least one new bed each year, for it also doubles as a compost facility. After the bed is constructed, we place the wood chips in it to kill off the grass underneath. All household wastes not fed to the pets or livestock is buried in the bed, along with prunings, thinnings and tops from harvested veggies. This fills the bed as the season progresses and by fall, all that’s required is to top off with rotted manure, possibly some sand or topsoil and tuck it into bed for the winter. It will be fluffed and planted in the spring, and a new bed started.

These 28 beds fulfill the entire vegetable needs of our family of seven. For smaller families, there would be a surplus that could be sold. I also believe it could be quite suitable for larger scale enterprises. I am working with an Amish friend to design such a system to meet their needs and practices. Their soil is low, wet and of heavy clay content, making raised beds a perfect answer to their problems. Our sloping terrain requires shorter beds, but their flat ground allows for long, continuous beds. To provide adequate support for the soil in a longer construction, he’ll sharpen and drive his posts every six feet along the length of the bed, and nail in a cross board every six feet to hold the tops together. The heavy black plastic bags from his greenhouse potting soil will be tacked along the inside to hold the moisture.

He’ll plow and harrow the entire area before constructing the beds, which will be placed far enough apart to allow his team and spreader to pass between them. Sand from his sand pit, sawdust from his sawmill and manure from his barn will be placed in layers in the manure spreader. Plywood side shields will keep it from flinging over the sides of the bed as he spreads it over the space between the beds. Instead of our thick layer of wood chips, he’s planning on filling the bottom of his beds with tightly packed bales of spoiled hay. A few marathon-shoveling sessions will place the well-mixed ingredients along with the original soil from the ground into the beds. We’ve used the hay bales before and they work well as a space holder and water reservoir. As they rot and are brought to the surface, they add to the fertility and tilth of the soil.

Building the beds entails some labor and lumber expense, (unless you have your own mill like we do), filling them requires a LOT of effort. It works out best when they are built one or two at a time, spreading the work over the seasons. Once built, they require less labor than can be imagined to produce unbelievable crops. My rough estimate is that the raised beds produce 75% of our veggies with 25% of the labor while our flat garden requires 75% of the labor for 25% of the production. These numbers work for us.

Raised beds may not be right for everyone, and our way is not the only way. I have seen raised beds made from rows of 5’ diameter kiddy pools, and heard of a fellow who collected junk refrigerators from the dump, removed everything from the shell, shot the back full of holes and lined them up on their backs into a rainbow of colored enameled steel raised beds. Even rows of five-gallon pails filled with plants count as raised beds in my estimation. The point of the whole idea is to maximize the fun and productivity and minimize the work and hassle. Do it any way you care to, but do it if it’s right for you.