Adding general organic soil amendments, such as compost and other organic matter, to your gardens and flower beds in the fall or Spring prevents soil compaction and replenishes nutrients used by the previous year’s plantings. What’s more, fall and spring cleanup projects, lawn mowing and leaf raking, provide an abundance of free organic material that is ideal for use in organic soil improvements. Your gardens will thrive with a boost from organic amendments at either time of year.
Why Amend Your Soil?
Periodic organic soil improvements are needed to continuously meet your garden’s demands for nutrients. Without adequate soil nutrition, the health and yield of blooms, vegetables and fruits will suffer. Additionally, organic soil amendments are used to correct drainage problems and increase aeration of the soil. Improving your soil in the fall gives your garden adequate time to process and break down organics, so Spring is met with a soil preparation that is balanced in both nutrition and texture. Spring organic amendments deliver new, nutrient packed organic soil at the ready for plant growth and health.
What to Add
Before you begin, determine what your organic soil is lacking. The experience of the past planting season should be an indication as to whether or not drainage is an issue you need to address. If your soil was too sandy, draining too quickly and drying out your plants, use organic matter to build up the soil and help your garden and plants retain moisture in the season to come. Alternatively, clay heavy soils do not properly drain, leaving you with rotting seeds and roots in too wet soil or standing water. Cutting organic soil with sand will increase the ability of clay laden soils to drain.
Garden centers and nurseries carry a variety of soil tests that you can perform at home to determine nutritional deficiencies and levels of soil acidity. Use these tests to decide what you need to add before you proceed with amending your soil organically.
TIP: Our expert gardening adviser, Rachel Klein suggests, "If you want a general idea of your soil type before purchasing a soil test, consider this quick home-test. Simply dig down about 10 centimeters in your garden and grab a handful of soil. Squeeze it into a ball. Loamy soil forms a rough ball but crumbles readily. Clay soil will form a smooth ball that stays hard when dry. Sandy soil will not stay together at all. Loamy soil is the ideal garden soil because it contains a mixture of different size soil particles."
Many organics naturally occurring in your yard are ideal for building up your organic garden soil. A simple lawn mowing provides one of the best resources for organic garden soil improvement. Mow your lawn and bag or rake the shredded leaves and grass clippings to work into your soil. Not only will the grass and leaf bits break down to provide essential soil nutrients, but they will work to loosen and aerate the soil, increasing root health during the next spring and summer growing season. This will aid in soil drainage too.
Some of the most commonly added and least expensive organic amendments for your organic garden soil are:
- peat moss
- leaf mold
Compost - Victory Garden author James Crockett calls compost, “the caviar of organic materials,” for its ability to retain moisture and provide numerous rich nutrients to organic garden soil. Composted matter has a rich, dark, crumbly consistency, somewhat coarse in texture. The nutrients in a given compost are dependent upon what went into it. A soil test can be helpful in determining the nutritional composition of your compost if it is of concern to you.
Sand - Mixing sand into heavy soils helps to improve the drainage of the soil, and the loosened soil allows roots to grow. Many gardeners recommend using contractor’s or builder’s sand for its natural coarseness. The grains in a builder’s sand are usually larger than something like a beach or play sand, helping to decrease organic soil compaction.
Manure - Composted manure is another organic amendment that is well known for the benefits it brings to your organic garden soil. Composted manure resembles a very rich, dark soil. It is easy to work into the soil, improving organic soil drainage and moisture retention. Composted manure is very high in nitrogen.
TIP: Rachel warns you, "Fresh manure can harm plants due to the high levels of ammonia. To avoid this problem, use only aged manure (at least 6 months old).]
Lime - A byproduct of mining processes, lime (or limestone as it may be called) is a white, chalky powder used on organic lawns and gardens to lower soil acidity. Lime contains calcium and magnesium, which reduce soil pH. Lime is now widely available in a pelletized form which is not as dusty as powdered lime and is more comfortable to work with.
Peat Moss - Peat moss is a naturally occurring lightweight moss, grown commercially for gardening use and sold in garden centers. Peat moss acts as a sponge in the soil, dramatically improving an organic soil’s ability to retain moisture.
TIP: Rachel adds, "Sphagnum peat moss is an excellent type of peat because it is less decomposed and will last longer than other types. Before use, moisten the peat moss to better incorporate it into your soil."
Leaf Mold - Leaf mold is a mixture of composted leaves. A cost free organic amendment made from leaves raked from your yard, leaf mold slowly releases nitrogen and potassium into the soil.
Sawdust - Sawdust or wood chips are made from chipped or ground trees, trimmings and bark. Ground wood products are helpful to improve the drainage and texture of organic garden soils. Mixing sawdust or ground wood into your organic soil gives it a light, airy texture.
TIP: Rachel adds, "Wood chips have the slowest decomposition rate of all of the amendments. This means that they can last the longest in your soil, possibly years."
You will need four cubic yards of organic amendment per 1,000 square feet of soil area.
Step 1 - Check Soil Conditions
If the soil is too wet from periods of rain, let the soil dry for a few days as wet, heavy soils are difficult to work. For dry soil or new garden plots that have not been worked before, a thorough watering a few days ahead of time will make your job easier.
Step 2 - Loosen the Soil
To apply amendments, first loosen the soil. Using a rototiller for large areas or a fork and spade for existing beds, break up the soil to a depth of approximately 6 to 12inches (the lower range is appropriate for existing beds).
Step 3 - Mix in Organic Matter
With a shovel, spread your composts and organic amendments evenly over the garden patch. Blend the organic nutrients into the soil using a gardening fork or your rototiller (if you don‘t own a rototiller, they are often available for rental through home centers). After you have thoroughly worked the materials into the garden soil, level the area with a rake.
TIP: Rachel suggests, "Add a 2-inch layer of organic material over the surface of the soil and mix it into the top 4 to 12 inches."
Your organic soil is now properly replenished for the upcoming planting season. Over the course of time, the organic amendments you added will continue to break down and build a high quality organic soil for a plentiful gardening season ahead, effecting a slow-release of nutrients that is of most use to your garden . You can repeat the soil and acidity tests every spring prior to planting, to determine if further adjustment is needed. Over the course of the spring and summer growing season, begin a pile of compost to naturally amend and replenish your organic garden soil in the fall with rich organic matter harvested from your yard and kitchen.