Wednesday, March 5, 2014

Raised Beds

     One of the easiest garden features to plan for is a raised bed for your cut flowers, vegetables or other annuals. Raised beds provide a number of benefits -- especially for the clay soil we have in Chicago:

     1. They allow the soil to warm up faster, making it possible to plant earlier in the season.

     2. They encourage better drainage. This is especially important during our soggy springs. A raised bed will dry out when all the soil around it is muddy. Again, this makes it possible to plant earlier in the season.

     3. Finally, raised beds discourage human and pet traffic from the areas in which your plants are trying to get started.

     Raised beds can be built in an infinite variety of shapes,sizes, and materials. I will deal only with the simplest and most utilitarian today.

This set of packed-earth raised beds owes its avant-garde look
 to the fact that we had a heavy rain shortly after it was built. 

     The simplest beds are made with nothing more than a shovel. You can mark out your beds and paths with string. Then you dig out on the path side of the string and dump each shovelful on the bed side of the string. Rake the paths smooth and tamp the top and sides of the beds, and you are done.

     A more permanent and attractive alternative is a bed made of wood -- preferably rot-resistant cedar or redwood. The new pressure treated pine, called AC2, claims to be suitable for raised beds, but I would prefer not to use it around fruit or vegetables.


     You should give the dimensions of your beds some thought before rushing out to buy lumber. First and foremost, you should be able to reach every part of your bed easily from "outside the box".  (That is, you should not build beds like the ones in the first photo.)  Beds can be 8-10 feet long, but should be only 3-4 feet wide, and less than that if you can only reach in from one side. Better two narrow beds than one large one. Paths between beds should be 2 to 2 1/2 feet wide --or wider than  your garden cart or wheelchair. The beds can be 8 inches to 16 inches high or higher. Higher beds require more wood and more soil, but they also provide a better barrier to pets and make the beds more accessible to those of us whose joints are getting a bit creaky.

     For now, I am going to put my creaky joints to work on the latest snow.