It’s natural after a long, busy summer for people to welcome the chill of autumn and assume all work in the garden will cease.
Yet fall is the best time to be proactive for the spring and improve the soil for next year’s garden. By adding soil amendments to your client’s yard in the fall, they will have all winter to break down and restore the nutrients plants will need.
There are multiple ways to improve your customer’s soil but the first step is determining what nutrients are actually in need of replenishing.
Test the soil
Testing the soil is often brushed off, like when the dentist tells you to you floss your teeth, but there is a reason why this first step should be made a priority. Without a soil test, you are often walking in blind as to what your client’s yard really needs. You can assume that the conditions are relatively the same in your service area, but doing so can result in using the incorrect fertilizer or amount of soil amendment.
Getting a proper interpretation of a soil test requires you to take a representative sample of soil. Separate samples should come from areas that differ in texture, color and previous applications of fertilizers, organic amendments and lime.
According to the University of Minnesota Extension, sample depths vary as listed below:
- Sample garden soils and soils to be used for establishing a lawn to a depth of 6 inches.
- Sample established turfgrass to a depth of 3 inches.
- For trees and shrubs, sample to a 12 inch depth.
Change the pH
The soil’s pH level is important because a majority of the necessary plant nutrients are soluble at levels of 6.5 to 6.8, but most plants can thrive anywhere from 5.5 to 7.0. When the levels are too low or too high, plants can suffer from problems like iron deficiencies or plant poisoning when a nutrient is available at toxic levels.
For acidic soils, the most common way to raise the pH is to add lime, which either is calcitic limestone or dolomitic limestone. For soils low in magnesium, dolomitic limestone is better. Most liming materials take several months to react, so they should be incorporated at a depth of 6 inches well before planting time.
The application rate for lime depends on the current pH, the desired pH and the soil texture. To raise the pH by about one point, follow this rule of thumb. For sandy soils, three to four pounds of ground limestone should be added per 100 square feet. In loam, seven to eight pounds per 100 square feet and in clay soil eight to 10 pounds per 100 square feet.
Alkaline soils are common in arid regions and can be remedied with sulfur. The application rate can be determined in the same way as lime by looking at the current pH, desired pH and soil type. To lower the pH by one point in sandy soils, add one pound of ground sulfur per 100 square feet. In loam, add 1.5 to 2 pounds per 100 square feet and add 2 pounds per 100 square feet in clay soil.
Add organic material
Organic material like compost, shredded leaves and organic nutrients are all ideal materials to add in the fall as they help provide soil microbes food and protect the soil from being bare during the winter.
Compost is a good material to add as it helps nourish microbes, and it also means less work for homeowners as it is able to passively work in the soil over in the fall and winter thanks to rainy or snowy weather.
Additionally, spring-applied compost can attract a number of pests. Raw organic materials like shredded leaves can help retain moisture and protects the microscopic organisms in the soil, while returning phosphorous and potassium to the soil.
Add some slow-release nitrogen fertilizers with the shredded leaves in the soil to speed the decomposition and keep microbes from using all the nitrogen in the soil. Organic soil amendments like bone meal are similar to inorganic slow-release fertilizers and have a low burn potential. They are useful where leaching of nitrogen is a concern.
An even better way to feed the soil is by using living plants themselves, and it makes sense considering that most the organic materials that have been mentioned earlier in the article come from a plant.
In northern regions, cover crops need to be established before winter, so plant these 30 to 60 days before the first frost. In areas with more moderate winters, these cover crops can be planted any time in the fall. They are able to work as a cover, a fertilizer and a way to take up leftover soil nutrients to hold in the winter.
Red clover, legumes and many cereal grains can be used as “green manure.” In the spring, the cover crop should be mowed before it can go to seed and then tilled into the soil.
Wait at least three weeks for the cover crop to decompose before using the bed for spring planting.