For The Answer
Weekly Express-News Article
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist
Saturday, February 2, 2008
February is a good month to begin vegetable gardening in
If you are considering a vegetable garden for the first
time, the recommended way to raise vegetables is in a raised bed. Use used railroad ties for the border. Cement blocks, cedar lumber, treated lumber,
plastic lumber, and rock all work as well.
The rock and cement blocks work best if they are mortared together, but
it is not absolutely necessary.
The railroad ties only need to be one tie high, but can
be built two or even three timbers tall.
The tall beds are especially desirable for gardeners who work from a
wheel chair or have trouble bending over.
A bed that is only one timber tall does not require that the timbers be
fastened. They are heavy enough to stay
put if the soil is leveled under the railroad tie. The best fastening system seems to be to
drill holes in the ties and use a cut piece of 3/8 or ½ inch rebar cut to the
thickness of the ties (one, two or three tall) with an extra foot of rebar that
can be pounded into the ground to securely hold the structure in place.
It takes about two cubic yards of landscape mix to fill
an eight foot by eight foot bed one railroad tie tall. Add two cubic yards of soil for each eight
foot section that is added to the original section and add two cubic yards for
each additional layer in the air. An
eight foot by 24 foot garden would require six cubic yards of soil mix. A bed with the same dimensions, three timbers
tall would require 18 cubic yards of mix.
An eight foot by 24 vegetable garden is a good size for a small
A soil mix with one-third compost, one-third washed sand
and one-third native soil works well. It
is easiest to buy it. The landscape
light soil sold at horticultural supply retailers such as Keller Material,
Fertile Garden Supply or Garden Ville has about 50% compost. It works well. Expect to refresh and replenish the bed with
compost every two years as the original organic material decomposes.
Vegetables are not xeriscape plants. To maximize yields you do have to irrigate
every few days. The best irrigation
system for a raised bed vegetable garden is a drip system. Lines are laid along the row with emitters
every foot or some other interval. Drip
systems are very efficient; they place the water at the base of the plant with
almost no loss to evaporation or wind. The
home improvement stores and retail nurseries have drip irrigation kits or you
can ask an irrigation company to put one in for you. The kits are easy to do and are very
To make your watering even more efficient, mulch the
vegetables. Live oak leaves are my
favorite mulch. They are easy to work
with and eventually decompose with minimal nitrogen deficit.
Fertilize the vegetable garden with slow release lawn
fertilizer before planting. One cup per
50 square feet is a good amount.
Sidedress the vegetables every month with a cup per eight foot row. Onions, greens and tomatoes are especially
hungry for nutrients. Root crops require
slightly less fertilizer.