Native Soil in Raised Bed Gardens
Challenging native soil conditions can be overcome by using a raised bed garden.
Raised beds can place plants at eye level for better viewing of pest problems. When the bed is contained within a structure, you are better able to really get in there and work on your bed without compromising the overall shape.
I also prefer not having to bend over to maintain the bed. Just adding a little convenience makes it easier to work in the garden, even on those days when I might want to relax with a cold drink. Trust me; I have days like this too.
Do you live in an area with hard-packed dirt, heavy clay (like my red Atlanta clay), fine-grained sand, or is your home surrounded by concrete? Maybe, you've done a soil test and found lead or some other contaminant in your native soil?
Elevating garden surfaces will raise your plants above problem soil and prevent plant roots from being exposed to these contaminants. By using a loft bed, there really are no surface issues that will prevent you from gardening.
When your soil bed is higher than the surrounding terrain, you can control its health and drainage. So, no matter how bad the land you start with, anyone anywhere can grow a productive raised bed garden.
Frankly, I also just love the look of the raised bed. I have found their aesthetic value to be a great benefit to my property. Given these options, I can't imagine gardening without a raised bed.
Do the benefits of a loft bed outweigh the cost?
There are many variables that can determine whether a raised bed is your best garden choice. Some great gardeners prefer underground gardening. A regular on these podcasts has mound beds in the underground garden, and he wouldn't have it any other way.
In the Lee Empire Gardens, stacked bed inner gardens line up.
Building a loft bed can be expensive. It doesn't need to, but it can. In 2009 I was asked to build a full garden (including plants) for $25 or less and I was lucky enough to find 110 year old barn wood for my raised bed structure. It may be worth checking sites like Freecycle.org or Craigslist.org for material that can be repurposed.
Some other potential disadvantages of loft beds:
their persistence. For most people, this is a benefit, but if there is a chance that you will need to relocate your garden in the next few years, the permanent raised bed structure will need to be removed.
Uplifted soils are more susceptible to heat and cold than topsoils. If the sidewalls of your bed are not very thick, the soil and plants in close proximity may be affected by extreme conditions.
Raised soil dries faster than topsoil. In this series, I'll go over some ways to significantly reduce this adverse effect, but the fact remains.
Raised beds require space between the beds to move through the garden's pathways. If you have very limited real estate, losing some of it to walkable space could be a deal breaker.
garden area planning
There are countless raised bed designs and variations out there. We'll discuss more next week, but first, consider your space. Remember, these guidelines and principles apply best to edible gardens—growing fruits and vegetables.
You don't need a lot of space to build a raised bed garden. What you need is a place that gets full sun for most of the day - at least 6 hours. Those edible plants need lots of sunlight to fully mature and bear fruit for your harvest. Therefore, the sunniest area of your property will be the best garden spot.
If your property is shaded by many trees, you may want to consider some selective pruning to allow sunlight to reach your garden location. Be sure to check out the Growing a Greener World blog on the topic and considerations for it.
It is best if the garden area is relatively flat. Many of you are starting in hilly terrain, so I recommend digging into the mountains if possible. Flatten the area as much as possible before building.
If your location is not level and you don't have the ability to level the ground, keep in mind that your raised bed surface will need to be level once this is done. Therefore, starting with an uneven surface needs to be considered in your overall design.
Make sure the raised bed area has easy access to water. Is there a faucet nearby? If not, is it feasible to run a garden hose from the faucet to the garden area?
It's easy to forget that a pulled garden hose needs to be pulled back regularly (if not daily) for trimming, using the hose elsewhere, preventing it from being chewed by dogs, etc. Water is key to gardening success, so you want to make sure your approach is practical for you.
Also consider being close to your home. I strongly advocate going to the garden every day. Take at least some time to enjoy the beauty of what you've built. Taking some time each day can also help you spot pests and diseases early.
Let's be realistic. If your garden is tucked away on the other side of the yard, and that distance feels like a long walk after a long day; you may be inclined to sit in your favorite chair. And don't forget, you want these garden foods as close to the kitchen as possible for a quick dinner. Why plant it if you're too busy harvesting and eating it?
Raised bed size considerations
You've no doubt seen dozens, if not hundreds, of pictures of other gardens. So you know that beds come in all sizes and shapes. I've also seen almost everything - even plants inserted directly into garden soil bags (which I don't recommend). Here are my recommended guides:
1. Height: 12-18 inches is ideal, but even as low as 6 inches will work and increase productivity. Most feeder roots are in the first 6 inches, but the deeper the roots, the taller the shoots. Going over 18 inches can cause more structural problems due to the weight and pressure of all the soil.
Think about what type of crops you want to grow (root vegetables that need more space, herbs that need less space, etc.). Also consider the foundation you will be building on. Will the surface allow soil to erode the bottom (higher), or will it be affected by the weight of the bed (not too high)?
Provide as much and practical space as possible for your plant roots to grow. (If you check out last week's podcast, you'll know that 18 inches of depth is also the perfect seat height.)
2. Width: four feet are perfect, three feet can also be used. Four feet provides more flexibility for spacing the rows, but more importantly, not exceeding that width will allow you to easily reach the center from either side of the bed. Importantly, you don't have to walk into the bed to weed, plant, etc., as this can compact the soil and affect drainage and overall health.
3. Length: whatever suits your needs. You can build 4'x4' squares. You can build 4'x20' rows. Your length is only limited by your space and budget, as long as you stick to the four-foot maximum width.
4. Shapes: As mentioned before, you can build squares, rectangles, T-shapes, circles, ovals, etc. As long as you can reach all areas of the bed from the edge (stay within 4 feet of the width), you're good to go.
Preparing the Garden Bed Area
Maybe you're really lucky and have a bare, flat, beautiful land just waiting for you to come and make your bed. Do not? Then you've given (or had to) a little blood, sweat and tears just like the rest of us to take over our gardens from turf, bushes or weeds.
If your space is currently a lawn:
Rent a sod cutter to quickly and easily remove sod - but be aware that this will affect your budget.
Dig the sod the old-fashioned way. Hello Shovel, my old friend.
Strangle and compost high-maintenance grasses. If you're willing to wait a while (months) this method will provide a nutrient-rich foundation for your garden bed. I list the steps for this "no-till method" in my no-till gardening vlog
If your space is currently overgrown:
sunburn the area. Suning takes some time (4-8 weeks), but it's a great way to kill most weed growth and seeds 2-3 inches below the soil surface. Sunning utilizes captured moisture and heat and is best done during the hottest months of summer.
To tan, trim the area as low as possible to the ground, then wet it thoroughly - really soak it up. Then, cover the area with clear plastic sheeting (clear plastic allows more heat from the sun to penetrate to the soil surface than black or cloudy plastic).
The key to sun exposure is to ensure a tight seal around the edges of the plastic. Your goal is to trap all the moisture underneath, not provide pockets for heat to escape. It's best to bury the plastic edge under an inch or so of dirt.
Check the area regularly throughout the summer to make sure the plastic is still well sealed. If any holes were poked in the plastic at any point during sun exposure, cover them with tape.
Do not keep plastic for more than eight weeks at most. Sun exposure kills some of the beneficial microbes in the soil, but they quickly repopulate the area. Keep in mind that this process kills weeds down to about 3 inches of soil, so if you dig after sun exposure, you'll bring those deeper weed seeds back to the surface, making you sadder even more.
