Raised beds can lower garden's maintenance
By Mary Collister, Times Correspondent
Published Wednesday, May 20, 2009
Raised beds are versatile, easy to use, and have many advantages over traditional gardening. And they give us the opportunity to have better soil and use less water.
A raised bed allows easy control of your soil mix. Drainage, texture and nutritional value can be manipulated. Because you can customize soil mixtures in your raised beds, you can greatly improve soil drainage for plants. Raising your garden bed even 8 inches above the ground greatly improves drainage.
Another advantage is the ability to adjust the height of the bed. Some beds are constructed so you don't step into your raised beds for maintenance. You can produce more fruits and vegetables in the same amount of space that you'd use in a traditional garden plot. The perfect soil mix helps with this.
Weeds are easily removed, and pests are easier to spot and remove. Landscape material can be used to cut down on weeds.
Watering is more efficient, as you irrigate only where plants are growing and not the walking spaces between your garden rows. Vegetable and fruiting plants normally need more water than ornamental plants, so you can concentrate water where it is needed.
A low-volume irrigation system is easy to add in a raised bed, which helps minimize the amount of water used. And you can grow your plants closer together, which helps to shade the soil and reduces evaporation.
If you think a raised bed is for you, plan ahead. Come up with a good design, and it will last you for years. A good basic design is usually about 4 feet wide and can be any length that fits in the area you want to use, although a longer bed is not necessarily better. Two medium length beds with a space between them will make it easier to walk around the beds and work plants from both sides. Keeping it 4 feet wide lets you work from either side without having to step into the planting area once your plants and seeds are added.
When placing the bed, make sure it will receive adequate sunlight. Note any shade trees or barriers such as a fence that may cast shadows. North-south orientation tends to work best.
The bed should be at last 8 to 10 inches deep. You may want it deeper if you are growing large ornamentals, fruit trees or bushes such as blueberries.
You can make raised beds from such common materials as concrete blocks, bricks, railroad ties, pressure-treated lumber, etc. Railroad ties need to be completely dry before using, as leaking creosote can affect your plants. Pressure-treated lumber can be unsafe for use in the garden if treated with such chemicals as pentachlorophenol.
You can go as simple or as complicated as you want. If you want to spend more money, cedar has a long life and looks good. You can also buy raised bed kits online. You might try Clean Air Gardening or Mastergardening.Com. Use your favorite search engine, and you'll come up with many options.
Once you construct the bed, you'll want to fill it with a good soil mix. Fill the bed with one half organic matter such as compost and one half soil, plus some sand or fine grit mixed throughout for drainage. Filling a raised bed requires a large volume of material.
Figure how much you'll need by multiplying the width times the length. Soil and compost are sold in bags or by the cubic yard. A cubic yard is 3 by 3 by 3 feet or 27 cubic feet. Availability may determine whether you use bagged soil or buy the soil in bulk. Normally bagged material is much more expensive then bulk, but make sure you take into account the cost of delivery.
You will need a mixture of materials to provide a soil mix with good fertility, good drainage and good moisture-holding abilities. It is best to loosen the native soil at the bottom of the bed and mix that with your added soil to avoid creating two distinct layers. Also add ample organic matter, especially good quality compost, in addition to the soil and thoroughly mix them.
The soil will settle over time, so add regular additions of organic matter to maintain soil depth in the bed. Using organic mulch year-round will also help feed and replenish the soil. Another option is to cover and protect the soil surface by growing a cover crop every winter and turning that under each spring as a source of organic matter. Any green crop such as rye grass or legumes will work.
You'll find the raised bed easier to maintain than your typical garden and a perfect spot for growing fruits and vegetables for your family. Don't forget to add a few flowers for color and those informal bouquets.