by Glenn Davis, UCCE Master
Gardener, El Dorado County
February, 2003
Most gardeners plant their vegetable gardens according to the
suggested spacing on the seed package. The vegetable garden that evolves has
rows or mounds of vegetables of the same type adjacent to each other. If you
have good fertile soil you might want to consider ‘intercropping’ your
vegetables. Intercropping is a term used to describe the mixing of different
vegetable crops in the same garden area.
You can intercrop in many different ways. The first thing you
need to know is the amount of direct sun your garden gets during the prime
growing period, usually May through August. The sun’s location dictates where
you might locate low or tall plants. As an example, if you locate tall plants
on the north side of the garden, the sun will heat the remainder of the garden
and shade-loving plants will be eliminated from your garden. On the other hand,
if you locate tall plants on the south side of the garden there will be some
shade on the north side and you can include some shade-loving plants in your
garden. Some shade-loving plants that can be intercropped with sun-loving
plants include beans, beets, chard, leeks, peas, radishes, and turnips.
Intercropping also involves using plants with complementary
foliage. Plants that do not have large leaves, such as corn, can provide a
shelter and filtered sun for lower, larger leaved plants such as lettuce. Corn
stalks can also be used as a support for some vegetable vines that mature after
the corn has been harvested.
Timing your planting is also important. Lettuce can handle the
light sun of spring and fall, but needs to be protected during the heat of
summer. Planting it so it receives shade from other plants in the summer will ensure
that it doesn’t bolt with the heat. Keep in mind the length of time it takes a
vegetable to mature; radishes as an example are a very quick crop while peppers
might take the entire summer. It’s a good idea to intercrop slow growing
vegetables with fast growing vegetables, but keep in mind the light and heat
needs of each.
If you intercrop your vegetables consider the vertical space
available in your garden. Many vegetables can be growing on trellises; squash,
beans, cucumbers, peas, melons and tomatoes are just a few of the more obvious.
The inclusion of trellises
can also provide you with some shade areas in the garden if they are needed.
Many narrow leafed
plants, leeks, shallots, garlic and onions can easily fit between leafy
vegetables. Consideration should also be given to root size. Plants placed
close together will compete for nutrients in the root zone. Select plants that
will feed at different times and at different depths. Roots, especially the
small feeder roots, are much more extensive than the average person thinks. A
radish root might go down 2-3 feet while a beet can reach 10 feet in depth. The
top foliage is not an indicator of root size or depth. Foliage can vary with
the amount of sunlight; generally, foliage increases in area as the plant
looses sunlight.
By mixing your vegetable crop you diversify the food source of
many plant inhabitants. You are providing shelter and diversity to beneficial
insects while providing a limited food source to pests. A garden area with a
single crop is more susceptible to pests than a garden with diversified
plantings.
Intercropping is a good gardening method for people with
limited gardening space. It requires more planning and preparation than a
traditional garden, but the successful use of space and good garden practices
can make it a great project for the home gardener.
For more information on vegetable gardening attend the El
Dorado County Master Gardener Class, “Vegetable Gardening” on March 1, 2003,
9 am -12, 311 Fairlane,
Placerville. If you have any other questions contact El Dorado County Master
Gardeners at (530) 621-5512, Monday through Friday, 9:00 AM to noon.