Two Solutions For Amendment-Weary Gardeners
It’s trite but true: You never appreciate what you have until it’s gone. When I lived in Illinois I took soil for granted. With 12 feet or more of black dirt, if you wanted a garden all you did was bury a seed, add some water and step back before the plant hit you in the nose.
Then I moved to the Southern U.S., which arguably has the worst soil in the country. For most of us down here, that means clay. Red clay. And blue clay. And gray clay. Clay so pure you can dig it up and throw it on a potter’s wheel.
Containers and Raised Beds
With a lot of time, hard work and truckloads of amendments, clay can be turned into rich, friable soil. But if you want a garden right now, that means working above the ground in containers and raised beds.
Is there a difference between them? Superficially, containers are thought of as being small and raised beds as being large, but there’s a more fundamental difference. Containers have bottoms, and the contents are not in touch with the ground. Raised beds, on the other hand, do not have bottoms and, in effect, form a top layer to the natural soil. This has a great effect on how you raise plants in each of them.
On the face of it, nothing is simpler than container gardening. You merely fill a container – be it a terra-cotta flowerpot or a wooden half-barrel – with soil and set your seeds or plants in it.
But because they are raised up in the air, special conditions apply to containers. They dry out much more quickly than the surrounding ground, for instance, because they warm from the sides as well as the open top.
This means you have to water much more frequently – sometimes twice a day in the summer. As a result, nutrients leach out quickly. Which, in turn, means you have to add fertilizer more frequently.
Large containers such as these 20-gallon tubs make it easier to control moisture and nutrient levels.
A Big Solution
The larger the container and the fewer the plants in it, the less this is a problem. For instance, in the past I have grown tomatoes in 5-gallon buckets, and they required constant attention to moisture and nutrient levels. Recently, I started using 20-gallon tubs that cattle feed supplements come in. As a result, they hold moisture longer and require less fertilizer.
My English friend John Yeoman often goes in the opposite direction. He recycles empty milk jugs to create a wall of planters. To do this, he cuts the tops off at the shoulders then attaches the remaining pots to a lathing strip. A series of these strips covering an unsightly wall makes a beautiful floral display, or can be used for growing veggies with one plant in each pot. However, watering this is an almost constant affair.
Whether building a bed in situ or with sidewalls, a weed guard should be laid down first to deter perennial weeds from sprouting.
Contrary to popular belief, raised beds do not need sidewalls. Here, Barbara Elliott plants seedlings into an in situ bed raised 8 inches above ground level.
Containment materials range from the strictly utilitarian to the decorative, such as this native stone bed.
One benefit of containers is that you can tailor the soil to the needs of the plants. For instance, acid-loving plants can have a mix that suits them without it affecting nearby plantings. Containers are also ideal for taming otherwise invasive plants because there’s no way for the roots to escape. For example, I have a large wooden planter growing sweet grass that keeps it from spreading beyond the borders I’ve set.
If you choose commercial containers, drainage is not a problem most times. However, if you build your own planter boxes or recycle buckets and tubs, drainage holes need to be added. The natural inclination is to drill them in the bottom, but the holes tend to clog up when you set such a container on the ground or a concrete patio.
A better bet is to drill the holes an inch or so up the sidewalls or incorporate short legs to raise the container slightly off the ground. Keep this in mind with commercial pots too. If the material won’t allow you to drill side holes, then put a layer of gravel or Styrofoam peanuts in the bottom before adding the soil mix.
Raised beds are a whole other ballpark. True, some of the same conditions apply. For instance, raised beds tend to warm up more quickly in the spring. And they do dry before the surrounding ground, albeit not as quickly as a similarly sized container.
By the same token, because they are nothing more than a hill of soil, raised beds have certain advantages that containers lack. For starters, the moisture and nutrients in the ground are available to the plants. Plus, even with heavy clay soils, there is more room for the roots to grow. This, in turn, breaks up the clay and softens it.
A perennial question is, “What should be used for the sidewalls?” The answer is whatever your aesthetic taste and pocketbook allow. Everything from boards to railway ties to bricks to cinderblock has been used. I have one bed flanking the porch that I built of native stone. And I’ve even seen beds made out of empty wine bottles buried neck-down to the shoulder.
In actuality, retaining walls aren’t needed at all. You can create an in situ bed by piling up the soil and amendments.
Roughly level the surface, wet down the bed and then use a hoe to gently slope the sides inwards. They’ll stay in place just fine, even through torrential downpours. Or you can fill the spaces between the beds with wood chips or decorative stones to help retain the beds.
Some people insist on tilling or plowing the ground before building a raised bed. Frankly, this is a lot of unnecessary work. By building the bed properly, you don’t have to work the ground at all.
Start by mowing any grass and weeds as close to the soil surface as possible. Mark off the dimensions of the bed with string and stakes or build your sidewalls. Then lay down a weed guard of newspaper, brown grocery bags or even old carpeting. This is important. If you skip this step, you’ll have a bed full of perennial weeds.
Newspaper should be laid very thick, at least seven layers. Grocery bags work with just one overlapping layer, but two laid perpendicular to each other are better. Either way, soak the paper well before laying it in place. Over time the paper will rot away, but by then the perennial weed seed will have mostly died.
Then fill the bed with the soil mix of your choice. Pile the soil at least 4 inches higher than you want the finished bed to be because it will settle, particularly if it’s heavy with compost or peat.
There is no size restriction on raised beds. But it’s a good idea to make them no wider than you can easily reach. For most people, 4 feet is the maximum since you can reach in 2 feet from either side to weed or do other work.
Sometimes small is better. I like to arrange a series of small raised beds for growing herbs and trailing veggies. Here again, sidewalls aren’t necessary.
I trial beans – as many as 10 varieties a year – in a group of in situ beds measuring only 5 feet long by 18 inches deep. At the same time, I have numerous herbs in mini-beds made by cutting rings from 55-gallon plastic barrels. Each of them is about a foot high.
Containers and raised beds let you grow flowers and vegetables no matter what the soil conditions may be.
So if your gardens are curtailed because of bad soil, give them a try.
(From State-by-State Gardening October 2004. Photos by Brook Elliott)