plants grow best in a fertile, well-drained soil of loamy texture.
Sandy loam soils, well-supplied with organic matter, are easily
worked and are quite productive. Very coarse, sandy soils dry out
rapidly and are difficult to maintain at a high level of fertility.
Clay soils are hard to work and usually remain wet until late in
the spring. These soils are often yellow or dark brown and sticky
when wet, or grayish in color where drainage is poor. Clay soils
tend to form a hard crust after a heavy rain and become so compacted
that the plant's root system is deprived of the oxygen required
for growth. Clay and sandy soils must be modified for successful
obtain a desirable soil for gardening, consider the following areas
of concern: water drainage, moisture condition at the time of working,
erosion, texture and structure, fertility and pH (acidity or alkalinity).
Satisfactory vegetable production cannot be expected on poorly-drained
soils. Where drainage problems exist, and where an outlet is available,
four-inch drain tile in lines 25 feet apart is suggested. The tile
should be at least 2 feet deep. The fall in the lines will depend
on the outlet and length of lines, but water needs a fall of at
least 2 inches per 100 feet of line.
In many home gardens, improving subsurface drainage with tile lines
is not practical. Therefore, surface drainage is very important.
The surface should be graded so that excess water will be removed
promptly, but in a controlled manner to prevent erosion. Leveling
will eliminate pockets and low spots where water tends to stand
for long periods. Adding organic matter to clay and clay-loam soils
will also improve drainage and aeration.
Growing vegetables in raised beds or on planting ridges is another
option for controlling drainage. However, keep in mind that proper
water management during periods of drought may be more difficult
in raised beds.
anxious gardeners work the soil in early spring when it is still
too wet. The soil should not be tilled or spaded until it is sufficiently
dry to crumble when worked Use the "squeeze" test to determine if
the soil is ready: use a spade to turn over a slice of soil about
6 inches deep, then pick up a handful of soil and squeeze it. If
the soil remains in a tight ball when pressure is released, wait
several days (without rainfall) before spading or tilling. If the
soil crumbles when pressure is released, it is ready for working.
Soils high in clay content are easily damaged if worked when wet.
Some clay soils benefit from fall tilling or spading. Such soils
will be loose and fluffy in the spring as a result of the conditioning
effect of winter freezing and thawing. Fall-worked soils often require
only leveling and a light raking in the spring before planting.
Fall-worked soils can be compacted quite easily, however, if worked
when too wet.
texture and structure can be modified by using soil conditioners.
Soil conditioners act to improve soil aeration, drainage, moisture-holding
capacity and tilth, or workability, of the soil. Commonly used soil
conditioners include compost, peat moss, sawdust, wood chips, composted
animal manures, green manure crops, coarse sand and perlite. By
incorporating coarse sand and organic matter into a garden soil,
the gardener can, over time, produce a desirable loamy-type soil.
The addition of fine sand, however, into some soils, especially
clay, will be detrimental to the soil structure.
A common mistake made when attempting to improve garden soil is
failing to use enough soil conditioning material. For soil which
is mostly clay or sand, large amounts of conditioners must be used
to effectively improve texture and structure.
Condition the soil by applying 3 to 4 inches of organic matter and,
if available, 1 to 2 inches of coarse sand uniformly over the surface
of the garden. Till or spade the material thoroughly into the top
8 to 10 inches of soil.
materials such as straw, fresh sawdust, wood chips, and shredded
bark require the addition of nitrogen fertilizer when they are incorporated
into the soil. The nitrogen provides extra nutrition for microbes
decomposing the added organic matter, preventing a temporary nitrogen
deficiency in the vegetable plants.
1/4 lb. of ammonium nitrate or ammonium sulfate for each bushel
of mulch material, or 2 lbs. per 100 sq. ft. of a complete fertilizer
such as 5-10-5, 8-8-8, 12-12-12 or similar analysis. If there is
any yellowing of the lower foliage and garden plants lack vigor
during early summer, apply additional nitrogen fertilizer.
soils benefit by being protected by a winter crop such as winter
rye. Winter rye is preferable for late (after September 15) cover
crops seedings and is seeded at a rate of 1/3 lb. per 100 sq. ft.
of garden area.
crops prevent soil erosion and add organic matter when turned under
in the spring. Cover crops should be turned over before growth is
so tall they are difficult to handle. Cover crops may be seeded
in August or September between garden rows before vegetables are
A soil test should be made to determine if limestone is needed to
adjust the pH of the soil. Most vegetables grow best under slightly
acid conditions with a pH of 6.0 to 6.8. See GreenShare Factsheet
on soil testing for more information.
from Marianne Riofrio and E.C. Wittmeyer, Ohio State University